8-inch woofer based speakers vs 5.25 and smaller. - AVS Forum
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post #1 of 152 Old 02-26-2010, 09:42 PM - Thread Starter
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Okay,

When comparing speakers for years and ultimately getting to design and tune my own car system this past year I have come to some conclusions that baffle me when I actually look at the landscape of crap designs that are on the market today.

I've observed the design of most home theater speakers concentrate on 'looks' before good sound. It's as if the speaker company were being run by salesmen and bean counters instead of engineers. When actually getting to compare what I KNOW sounds good vs what I see for home speakers, here is the conversation I believe took place in virtually all speaker companies "okay, we want small, cute speakers that fit the decor of homes, but what I want you guys with glasses to come up with is a way to make them sound good".

Now, I believe the engineers gave it their best shot and have really pulled off some marvelous feats to shrink the size of speakers down (the best innovation being the sub/sat idea) BUT they are still up against the wall in just what they can produce and current speakers have just gotten TOO SMALL!

When you keep in mind the principle and science behind speaker design doesn't change over time and the laws of physics don't change, let's take a minute to think about the original cabinet designs that engineers came up with to create 'high fidelity' many years ago. You saw large, refrigerator-sized boxes. Why? Because they promote better sound. You can stuff the box with polyfill in order to shrink the size of the box (cheating) and you can change the motor characteristics of the drivers (re-engineering) but ultimately you can only get cabinets so small before you lose either loudness or quality. You can't seem to have both unless you go 'big'. It's just a FACT of science.

I challenge you to do a test, which I already know the outcome of.

Take a set of 5 identical 2-way 5.25-inch woofer based speakers and setup an identically placed set of 8" 2-way (or better yet 3-way) bookshelf speakers that are like 20-inches tall in height. Run an IDENTICAL subwoofer (I'm even giving the small speakers the benefit a a large sub here).

Now configure each set of speakers with an identical receiver and you can even run 'auto-tune'. And test an identical soundtrack.

I now want to you concentrate on 'voice' content first. The 5.25-inch speaker's vocal quality vs the 8-inch speaker's vocal quality. You will notice a MUCH nicer depth of tone on the larger speaker. You will notice the same thing with the rear channels as well.

Side rant - [Modern surround channels are horrible sounding. I think surround channels need to get bigger. If you can't play it for 2-channel front sound, why the hell would you put it ANYWHERE in your setup? At least buy a nice 6.5" 2-way speaker. When buying my surround channel my rule is going to be to listen to it for 2-channel music and if it doesn't hold it's own, then ditch it (even if I have to play it in bi-pole or dipole mode).]

I don't think anyone should be using a different center channel than the left and right. I'm sick of seeing tower left/right speakers with a tiny center channel. Movies send 70+% of the sound to the center. It better be as good or BETTER than your left/right setup (and adding a second tiny woofer to the center design barely improves things here).

I'm on the fence with 6.5-inch woofers in satellites. They sound MUCH better than 5.25-inch woofers and smaller speakers but still seem to fall juuussst short of the full quality that 8-inch woofers give to the sound for depth, smoothness and balance. If any speaker in the setup can 'sacrifice' to use a 6.5-inch woofer, it's the surround channel but it's not ideal in my mind. Dual 6.5's are a close match to a single 8" in quality but still just don't seem as good.

You'll also notice that most 8" inch speakers can go louder and maintain quality bass with less 'breakup' than smaller speakers. At some point in the volume increase the smaller speakers suffer greatly.

There are some people that will argue to 10-inch woofers but in my opinion, for an 80Hz crossover, the difference will be very tough to notice. You would have to move that high-pass down to 50Hz-60Hz to notice a quality increase. In my opinion, the lower and STEEPER the subwoofer's lowpass, the better the quality of both sound and imaging. You may not hear the direction of 50Hz, but you can feel it and your body will interpret the direction of that sound when the sound gets loud.

Ideally, you want 10-inch woofers in your satellite speakers with a nice STEEP (24db/octave minimum but you will STILL get perceivable better sound quality with a 36db/octave slope) slope and 50Hz or 60Hz highpass.

Unfortunately the average home isn't going to accomodate speakers that large, no matter how much we like the sound of bigger speakers. So, 8-inch woofers are my compromise between quality and functional size. To go any smaller, you WILL hear an audible difference in quality sound re-production. I still believe a ultra-steep crossover slope will greatly improve the sound and imaging in modern systems and I think receiver and processor makers should use the digital realm to deliver steeper, better sounding crossover slopes. In my car stereo design, I found myself GREATLY improving my bass quality by increasing my high/low-pass slopes to 36db/octave. Until you've heard an ultra-steep crossover along with a deep frequency like 60Hz, you wouldn't believe how much more the subwoofer can "disappear", especially on very loud systems. I'm using my car system as an analogy but I plan to use some of the things I learned from my car design to help out my home theater buying.

Okay. Anyone else have similar thoughts?
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post #2 of 152 Old 02-26-2010, 10:36 PM
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Don't you mean, "mindlessly agree with my diatribe?"

No. Sound quality is based on much more than just size.

But then, you thrive on dissent from your firm yet untenable positions, don't you?
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post #3 of 152 Old 02-26-2010, 10:43 PM
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I use to think the same way till a few months ago.

They arnt just about the looks, the designs are moving in a certin direction for a reason.

Tower speakers to me just look like a stretched 80s type big speaker. They both have similar volume but for home theater we need lower tunnings then music speakers and we need them up higher off the floor.

With home theater you want a powered sub for the LFE channel so why stress the receiver for lows when they can do all the easy work and keep heat and distortion down. Having the 2 amps splits the work.

If you look at how most car stereos are setup they are similar to the tiny cube designs. The highs and mids are in the dash and the door and all the big woofers are hidden in the trunk. If everything is crossed over right you cant tell.

My brother has a setup in his car where all the speakers in the dash and door work off the receiver, and the big amp powers just the sub.

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post #4 of 152 Old 02-26-2010, 11:38 PM - Thread Starter
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I would like to ask you guys if you have actually tried to design a speaker system and really compared them to other drivers? I have tested larger vs smaller woofers for the midbass region (80Hz to 150Hz) for years and have NEVER heard a 5.25-inch driver sound better than a comparably designed 8-inch driver. EVER. And add the fact that 5.25-inch drivers are also less efficient (less loud) and you've got TWO really huge hits against a 5.25 inch woofer. Size matters and it matters big in the bass region. More cone area = more average and peak output with better control as the volume knob increases. You must increase the volume to louder levels to really hear the difference. 5.25's will 'poop out' while the 8's are still handling the power and sustained high output. 8's sound twice as effortless. The strain is not there on 8's.

You referenced a car stereo. I have a work associate who runs 5.25-inch midbass/midrange speakers crossedover at 80Hz while I run dedicated 8's bandpassed at 60Hz (I used 50Hz back when I compared our two systems) - 300Hz with 6.5-inch dedicated mids highpassed at 300Hz. My system absolutely DESTROYS his in sound quality. It's not even close. His 5.25's are breaking up LONG before my 8's and my system blends very well from the deep sub bass to the midbass and up to the untainted/dedicated oversized mids and silk dome tweets. Larger speakers give more effortless and clean sound at loud levels. The comparison isn't even close. Not even a competition.
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post #5 of 152 Old 02-27-2010, 12:01 AM
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I have to agree and disagree at the same time. Different implications and designs have different effect. What you say is true however that HT speakers are moving in the direction of smaller speakers with smaller drivers, perhaps due to increasing transportation costs, the ubiquitous WAF factor, and the wide use of subwoofers for LFE channels in HT. All these factors other than performance all contribute to the the undesirability of large speakers.

Perhaps one of the best speakers I have heard was a horn and a 15" woofer, my audiophile friend showed me. I have long forgotten the name, but he had two pairs of these and sold one for 10k to a local man. Who thought a 15" woofer could integrate so well. I on the other hand do not have the room for such large speakers and I have a pair of very slim speakers with 4 5.25" and 2 4" woofers however it does have a 12" powered sub on the side. These speakers have the advantage of having a narrow front baffle and they sure throw up a convincing soundstage.

No one is going to doubt the laws of physics, and that large drivers have a bigger advantage of moving more air with less distortion. But I will not say a larger woofer is always BETTEr than a smaller woofer which is properly implemented. I must say 4 5.25" and 2 4" woofers sound awfully tight.
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post #6 of 152 Old 02-27-2010, 12:25 AM - Thread Starter
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Quote:
Originally Posted by aboroth00 View Post

I have to agree and disagree at the same time. Different implications and designs have different effect. What you say is true however that HT speakers are moving in the direction of smaller speakers with smaller drivers, perhaps due to increasing transportation costs, the ubiquitous WAF factor, and the wide use of subwoofers for LFE channels in HT. All these factors other than performance all contribute to the the undesirability of large speakers.

Perhaps one of the best speakers I have heard was a horn and a 15" woofer, my audiophile friend showed me. I have long forgotten the name, but he had two pairs of these and sold one for 10k to a local man. Who thought a 15" woofer could integrate so well. I on the other hand do not have the room for such large speakers and I have a pair of very slim speakers with 4 5.25" and 2 4" woofers however it does have a 12" powered sub on the side. These speakers have the advantage of having a narrow front baffle and they sure throw up a convincing soundstage.

No one is going to doubt the laws of physics, and that large drivers have a bigger advantage of moving more air with less distortion. But I will not say a larger woofer is always BETTEr than a smaller woofer which is properly implemented. I must say 4 5.25" and 2 4" woofers sound awfully tight.

I'm sure if you did a direct A/B comparison against bookshelf speakers with 8's, you will find out that as the volume level goes up higher, the difference in clarity is very striking as well as the sharp hits of midbass. 4's and 5's only sound 'tight' at 90db SPL. When using an 80Hz - 100Hz highpass with a 24db/octave slope, when driving at 95db - 98db "average" SPL with 104db peaks, those 4's and 5's will sound like paper blowing in the wind with fluttering distortion while the 8's will remain largely clean. And this comparison will not be even close. It will be very easy to A/B/X the results.

There are only TWO ways to drive the 4's and 5's to that level and get them to sound audibly cleaner (but still not as clean as the 8's).

1. A higher highpass frequency (like 150Hz - 180Hz).
2. A steeper db/octave slope (like 36db - 48db/octave).

I've gone over these tests in my car enough times that it's pretty much a given in my mind. The smaller those speakers get the more you have to apply #1 and #2 I've listed to keep the sound from breaking up. At some point you will still get saturated sound even at 150Hz - 180Hz highpass and steep xover. That's when your speaker needs a bigger voice coil/better motor design. But when it comes to REAL bass, those 4's and 5's don't have it. The laws of physics don't change because it's 2010 instead of 1955. The very same speaker mechanics apply today that applied back then. Yeah, you may find new materials that help marginally improve distortion specs measured by sensitive microphones and digital software and you might be able to improve your speaker's motor a bit better, add some more xmax, etc but the science behind producing sound hasn't changed. It takes larger speakers to produce bass with great clarity and loud SPL's. Smaller speakers have improved in bass response but only marginally. 8's still slaughter 5's in bass response today. No different than in the 1950's when all the modern speaker information was being fleshed out by tests.

Ask yourself a question. When professional sound reinforcement engineers put together a concert audio system for a star musician, do they use anything smaller than 8's for bass? Never. In fact they use 10's and 12's for MIDRANGE and step up to 18's to 24's for bass. So, it goes. If you want it loud and clean, you will have to go BIG. There is no other way around that. In smaller places like a home or car, you don't need to use those huge speakers but you don't want to use 5's for bass either. That's just....bad.
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post #7 of 152 Old 02-27-2010, 12:52 AM
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I just think of my towers as really good midrange speakers with tweeters.

My towers have 2 seperate cabnets the top is seperated like a small bookshelf tuned higher. The bottom is a lower tuned midrange capable of playing some good midbass.

Im using the small setting on my receiver set to 100hz the towers can handle 45-20,000hz at 130/180 watts so since im crossing them over at 100hz wouldnt that help keep them together at a louder level?

My sub pickups up everything under 100 but i hear the towers playing bass lower i think it just slopes off after 100 so they do very little work really but they dont need to. The sub does all the hard work.

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post #8 of 152 Old 02-27-2010, 01:25 AM
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This is actually this first time I've heard 6.5" or even dual 6.5"s being labeled as satellite speakers. Interesting.
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post #9 of 152 Old 02-27-2010, 02:13 AM
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Quote:
Originally Posted by Timothy91 View Post

There are only TWO ways to drive the 4's and 5's to that level and get them to sound audibly cleaner (but still not as clean as the 8's).

1. A higher highpass frequency (like 150Hz - 180Hz).
2. A steeper db/octave slope (like 36db - 48db/octave).

3. Add more drivers.

I do agree with everything else you've said but like anything in engineering everything has a cost. A 5" driver will crossover better with most tweeters in 2 to 3K range than an 8". A smaller driver will also have better dispersion in the midrange frequencies.
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post #10 of 152 Old 02-27-2010, 04:26 AM
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Quote:
Originally Posted by Timothy91 View Post

I've gone over these tests in my car enough times that it's pretty much a given in my mind. The smaller those speakers get the more you have to apply #1 and #2 I've listed to keep the sound from breaking up. At some point you will still get saturated sound even at 150Hz - 180Hz highpass and steep xover. That's when your speaker needs a bigger voice coil/better motor design. But when it comes to REAL bass, those 4's and 5's don't have it. The laws of physics don't change because it's 2010 instead of 1955. The very same speaker mechanics apply today that applied back then. Yeah, you may find new materials that help marginally improve distortion specs measured by sensitive microphones and digital software and you might be able to improve your speaker's motor a bit better, add some more xmax, etc but the science behind producing sound hasn't changed. It takes larger speakers to produce bass with great clarity and loud SPL's. Smaller speakers have improved in bass response but only marginally. 8's still slaughter 5's in bass response today. No different than in the 1950's when all the modern speaker information was being fleshed out by tests.

Ask yourself a question. When professional sound reinforcement engineers put together a concert audio system for a star musician, do they use anything smaller than 8's for bass? Never. In fact they use 10's and 12's for MIDRANGE and step up to 18's to 24's for bass. So, it goes. If you want it loud and clean, you will have to go BIG. There is no other way around that. In smaller places like a home or car, you don't need to use those huge speakers but you don't want to use 5's for bass either. That's just....bad.

I agree with your claim that smaller drivers distort sooner than larger drivers with high spls due to physics and no one is going to disagree with you. And Ron is right that you can just add more drivers. Bookshelves are compromises on bass and no one is going to crank their bookshelves hoping to thump the house. I'm sure people with sats aren't going to expect large amounts of bass higher than the XO point of their sub.

If you compare a single 8" woofer to a single 5" woofer of course the 8" woofer is going to play louder with less distortion because it's not a fair comparison. We can increase spl by 3db if we double power or double the cone size, either by adding a cone or by making the cone larger. Thus we can compromise for a larger cone by having more smaller cones which will play to the same spl with less distortion than would one driver.

Also, you say that steeper crossovers are inherently better, but they do have drawbacks. As with anything, it has its pros and cons, while you gain a steeper slope you add risk to phase distortions and ringing. However you say we can have the crossover operate in the digital realm and not in the analog realm which negates these concerns, however then we have the problem of driver integration with such a steep crossover. Many speaker manufacturers use a 12, 24db crossover because it is a compromise, and a speaker can still sound good without such a steep crossover, and many other factors play into the selection of the crossover.

Again no one is disagreeing that larger drivers will play cleaner than smaller drives when you push the smaller driver beyond its break up point. It is understandable that bookshelves are compromises on what you're saying, and that these are compromises on performance ie high spl for liveability. However, a smaller thinner speaker with a narrow front baffle will be able to throw up a very large soundstage, as we can see, audio is all about compromises and there is no really objectively perfect speaker or speaker design in a room.
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Quote:
Originally Posted by aboroth00 View Post

I agree with your claim that smaller drivers distort sooner than larger drivers with high spls due to physics and no one is going to disagree with you. And Ron is right that you can just add more drivers. Bookshelves are compromises on bass and no one is going to crank their bookshelves hoping to thump the house. I'm sure people with sats aren't going to expect large amounts of bass higher than the XO point of their sub.

If you compare a single 8" woofer to a single 5" woofer of course the 8" woofer is going to play louder with less distortion because it's not a fair comparison. We can increase spl by 3db if we double power or double the cone size, either by adding a cone or by making the cone larger. Thus we can compromise for a larger cone by having more smaller cones which will play to the same spl with less distortion than would one driver.

Also, you say that steeper crossovers are inherently better, but they do have drawbacks. As with anything, it has its pros and cons, while you gain a steeper slope you add risk to phase distortions and ringing. However you say we can have the crossover operate in the digital realm and not in the analog realm which negates these concerns, however then we have the problem of driver integration with such a steep crossover. Many speaker manufacturers use a 12, 24db crossover because it is a compromise, and a speaker can still sound good without such a steep crossover, and many other factors play into the selection of the crossover.

Again no one is disagreeing that larger drivers will play cleaner than smaller drives when you push the smaller driver beyond its break up point. It is understandable that bookshelves are compromises on what you're saying, and that these are compromises on performance ie high spl for liveability. However, a smaller thinner speaker with a narrow front baffle will be able to throw up a very large soundstage, as we can see, audio is all about compromises and there is no really objectively perfect speaker or speaker design in a room.

I agree with your post as long as we are talking about similar drivers. If not then there are many smaller drivers that can outperform larger drivers. Here is a 6.5" mid-bass driver that will outperform a lot of 8" drivers. It will hang with most any 8" driver in it's price range when it comes to SPL and sound quality. http://www.diycable.com/main/product...roducts_id=538 It is now $69. The introductory special was $49.
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post #12 of 152 Old 02-27-2010, 05:14 AM
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IMO any thing less than 6" woofer isn't a woofer its a mid. But with that being said another reason for going to multiple smaller drivers in HT speakers is (1. More speakers= greater vertical sound distrobution and (2. Smaller drivers = narrower cabinet which let the highs and mids be un obstructed by a huge cabinet that a 12" driver would have to be in. My father-in-law has old Sony towers with a 1" tweeter a 3.5" mid and a 12" woofer and a 12" passive radiator. He replaced the woofer and passive radiator with newer stiffer versions. The bass is incredible and the highs and mids are good but only on axis because the boxes are soooo wide. I have speakers with 2 5" mid/woofers and a 1" tweeter and I have 2 powered subs 10" downfiring front ported. His towers have much more and cleaner tighter bass than my set up but my highs and mids sound much better off axis than his do.

Shawn
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post #13 of 152 Old 02-27-2010, 05:18 AM
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Old topic, new thread.......

DIYers that want performance already know that the pro audio drivers that are 10 to 15" are the best choices no days.

The regular crowd will never understand true performance.

5.25 drivers are fine for the family but when it comes to pure performance and dynamics they can not touch what we are doing. That goes for even 8" drivers!!

Critical two channel listening where you sit by yourself a couple feet away from your speaker need not appy to this discussion. This is all about Dynamics and higher SPL performance without distortion.

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post #14 of 152 Old 02-27-2010, 05:48 AM
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Old topic, new thread.......

DIYers that want performance already know that the pro audio drivers that are 10 to 15" are the best choices no days.

The regular crowd will never understand true performance.

5.25 drivers are fine for the family but when it comes to pure performance and dynamics they can not touch what we are doing. That goes for even 8" drivers!!

Critical two channel listening where you sit by yourself a couple feet away from your speaker need not appy to this discussion. This is all about Dynamics and higher SPL performance without distortion.

Since you're the agent that represents all DIYers, please allow me to ask a question even though I'm a mere peasant regular.
Does dual 5.25" or 6.5" arrays compete better or equal to the single larger woofers you mention in your stone tablet post?

'It's not what you don't know that hurts you; It's what you know, that just ain't so.'
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post #15 of 152 Old 02-27-2010, 06:18 AM
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Originally Posted by headedforhighend View Post

Since you're the agent that represents all DIYers, please allow me to ask a question even though I'm a mere peasant regular.
Does dual 5.25" or 6.5" arrays compete better or equal to the single larger woofers you mention in your stone tablet post?

I think i get what penn is getting at. I believe he's talking about a high spl application with HUGE dynamics such that ranges well above 100db in which bigger woofers are better suited to do the job. In this case I agree with penn. However, in my applications in my humble theater, i rarely push 95db and maybe when i'm feeling adventurous i wonder around further than 100db (maybe).

I'm sure he will agree that in a less taxing situation an equal cone size of 5.25" drivers relative to 8" drivers which are similar will yield similar results. There is one caveat of having larger drivers and thus large dynamics. You need a good high range driver which you can cross lower to your larger driver. But if you're listening at ear splitting SPLs I doubt you'll be paying attention to the mids, but instead be holding on for dear life as I'm sure penn does when he cranks his system

However, if i want large dynamics, a large room in which bass can propagate, I'll stick to the local IMAX; I simply can't afford all those drivers unfortunately
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post #16 of 152 Old 02-27-2010, 06:59 AM
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I'll back up Penn in that DIY'ers are typically DIY'ers because they can't get a commercially avalable consumer speaker that suits their specific needs. Quite a few of those folks may want extremely high performance and thus use multiple large subs, kilowatts of power, and beefy mains to match. Essentially a home theater that puts commercial theaters to shame.

Matching up a single 6.5" woofer to quad 18" subs just doesn't work. That is why there's been a big push lately in the DIY world for higher performing mains using 12" midbass/midrange and compression driver top ends.

As for twin 6.5's vs single large driver of equal cone area, there's compromises.
-The larger driver will start beaming first and it's easier to make it have more xmax. (Meaning the crossover point between it and the tweeter will have to be lower and, if it does have more xmax, will have a greater output in the bass area.)
-The smaller drivers will have two motors to share the power, so will likely handle more power. More power handling with equal efficiency means more output.
These are all assumptions and can be proved wrong with a number of various driver combinations.

YID DIY
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post #17 of 152 Old 02-27-2010, 07:50 AM - Thread Starter
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Quote:
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Also, you say that steeper crossovers are inherently better, but they do have drawbacks. As with anything, it has its pros and cons, while you gain a steeper slope you add risk to phase distortions and ringing.

At 36db/octave on my midbass in my car, I have no audible ringing. The sound is cleaner at loud levels and the sub "disappears". It's much better sounding than when using an 18db/octave set of slopes for hi/low pass. The difference for me in quality was in the slope depth. I also heard no phase distortions. I simply heard a more coherent, higher quality sound with much better vocal intelligibility and instrument mix separation. Sounds in the mix don't muffle over each other, even at high volumes.

Quote:


However you say we can have the crossover operate in the digital realm and not in the analog realm which negates these concerns, however then we have the problem of driver integration with such a steep crossover.

Driver integration issues? Explain. If anything steeper crossover slopes allow you to integrate speakers that otherwise wouldn't be able to be used in an application. Like those 5-inch woofers that bottom out and distort at 98db averages, might make it closer to that number before distorting with the help of a steeper highpass. Driver integration is enhanced by steeper slopes and sound quality/power handling also enhanced. The benefits also include as I said before, a more 'invisible' sounding sub and cleaner upper mids and less masking of midrange sounds which improves detail in the whole system.

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Many speaker manufacturers use a 12, 24db crossover because it is a compromise, and a speaker can still sound good without such a steep crossover, and many other factors play into the selection of the crossover.

These speakers with crossover compromises are sounding great usually because they are applying a weaker slope at the point where the driver is already having a natural rolloff. On the upper end of the frequency spectrum that isn't so bad (even though off-axis performance will suffer a bit). But at the lower end of the frequency spectrum of each driver, this limits the power handling and high output quality of the speaker.

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Again no one is disagreeing that larger drivers will play cleaner than smaller drives when you push the smaller driver beyond its break up point. It is understandable that bookshelves are compromises on what you're saying, and that these are compromises on performance ie high spl for liveability. However, a smaller thinner speaker with a narrow front baffle will be able to throw up a very large soundstage,

I've had large 3-way speaker baffles that in no way sounded like it was producing a compromised sound stage. A simply "tow-in" or angle-in move of the speaker to put it on-axis was enough to get great soundstaging. You can't fix poor midbass performance of small drivers. Even if you add an extra driver, that small driver STILL has more distortion than a larger speaker. It just gets a -3db "break". I'll still put an 8-inch driver up against two 5's at 98db SPL average outputs. Why? Because those two 5's will be running at 95db each, which will still put them in high distortion territory. Two 6.5's could likely pull it off though. But, what takes up more real estate on a speaker baffle? A single 8 or dual 6.5's? A single 8 will perform on par with dual 6.5's and take up less room.

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as we can see, audio is all about compromises and there is no really objectively perfect speaker or speaker design in a room.

That's correct. The ultimate audio experience is a recording done with a HRTF dummyhead with binaural microphones in it's ears and playback done with similarly designed earbud headphones for playback. That is the only TRUE way to produce the "you are there" experience. Anything else is a long series of compromises leading to playback in your room.
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post #18 of 152 Old 02-27-2010, 07:55 AM - Thread Starter
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Originally Posted by mjg100 View Post

I agree with your post as long as we are talking about similar drivers. If not then there are many smaller drivers that can outperform larger drivers. Here is a 6.5" mid-bass driver that will outperform a lot of 8" drivers. It will hang with most any 8" driver in it's price range when it comes to SPL and sound quality. http://www.diycable.com/main/product...roducts_id=538 It is now $69. The introductory special was $49.

Remember that with bass frequencies, for a 6.5" driver to perform up to an 8" driver, it must move equal amounts of air with it's cone. What is the only way to do that? Design a motor and surround for deeper xmax so it can have a longer 'throw'. What happens as a result? You need more amplifier power to move that bigger motor in and out enough times to duplicate the output of that 8-inch driver. That's a lot of extra engineering just to make up for a slightly different cone size and it's STILL less efficient than the 8-inch woofer at 80Hz and needs real good engineering to keep have the same distortion performance as a lesser 8-inch.

So, when comparing even close to similarly designed 6.5's and 8's, the 8's always win.

Oh, and here is the funniest FAIL of that link you posted:

So what is the catch? What did we trade to achieve all of these attributes? The answer is nothing...

Fs = 45.8HZ
Qes = 0.48
Qms = 6.37
Qts = 0.44
Vas = 9.61L
Sd = 131cm^2
Xmax = 12.5 mm one-way
Re = 6.4 Ohms
Le = 0.84 mH
BL = 10.79 N/A
Power: 125W Approx: No IEC testing conducted
Spl = 84.7 dB/1W/1M

FACEPALM!

Here is a pro 18" subwoofer:


Nominal Diameter: 380 mm (15 in)
Rated Impedance: 4 ohms (G)
8 ohms (H)
16 ohms (J)
Power Capacity1: 600 W AES continuous pink noise
Sensitivity: 97 dB SPL, 1 W, 1 m
Frequency Range3: 30 Hz 2.5 kHz
Power Compression4:
at - 10 dB power (60 W): 0.7 dB
at - 3 dB power (300 W): 2.5 dB
at rated power (600 W): 4.6 dB

I don't think professionals will be using 6.5's anytime soon, no matter how well engineered they are. Just to let you know how big of a slam the difference is between these drivers? The pro driver will produce SPL with 1-WATT which that 6.5-inch driver will need 25-watts to produce. After that, things get REAL ugly for the 6.5 as the pro driver is rated for 600-watts with much more favorable power compression specs (less loss of volume at higher wattages). The 6.5 isn't just beaten, you could add two more of these 6.5's to equal the 18's surface area (still get only 90db sensitivity), but 3 of these 6.5's STILL wouldn't touch that paper cone pro 18-inch driver. So, the multiple driver idea isn't really a solid way to produce results on par with a larger driver. A larger driver is simply 'better' at bass frequencies everytime. There is no substitute for a larger driver, period. You can get 'in the ballpark' with multiple drivers but still not do better.

How many of those 6.5-inch "mini burgers" does it take to equal the bass output of the pro 18" driver? Lets do the math:

84db SPL at 1-watt
add a 2nd driver = 87db at 1-watt (for each driver, 2-watts total)
add a 3rd driver = 90db at 1-watt (for each driver, 3-watts total)
add a 4th driver = 93db at 1-watt (for each driver, 4-watts total)
add a 5th driver = 96db at 1-watt (for each driver, 5-watts total)

So, to equal the sheer bass output of the 18" pro driver, you have to use 5 (that's five) of those 6.5's PLUS 5 (that's five) amplifiers of equal power. And according to that power rating on those 6.5's, you STILL won't equal the maximum possible SPL of that single 18" pro driver. Five of those 6.5's would keep up for about the first 80-watts then start to poop out from power compression and thermal issues while the 18" would still be pumping out massive waves of thunder into the hundreds of watts. Again further proof that size DOES matter at high SPL outputs and even adding multple 'smaller' drivers is no real substitute.
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Originally Posted by headedforhighend View Post

Since you're the agent that represents all DIYers, please allow me to ask a question even though I'm a mere peasant regular.
Does dual 5.25" or 6.5" arrays compete better or equal to the single larger woofers you mention in your stone tablet post?

Line arrays with 10 or more 5.25" drivers would be great too but they are a bitch to design and they are HUGE. Im not against them at all in the end though.

I do not represent anyone at all, Very few DIYer would consider line arrays because of the complexities (I know of one DIYer in our forum that did an incredible job, his member name escapes me right now, he is in Texas somewhere). THere is no reason to build something that complex if high SPL/ Low Distortion is the goal then there isnt anything better then B&C/JBL etc high pro audio drivers or even Lambda TD series woofers from AESpeaker (John the owner/builder of those drivers is a member on this board). You would be amazed to find out that that many of these run without beaming up past 1500Hz!! The Lamdba 15" woofer is an incredible design!!

The trick here is to find the tweeter that goes down below 2KHz. You can pretty well throw away the domes and look at Ribbons (mine Ribbons can do okay down to 2KHz with a steep slope crossover). In the end we are all trying to find that waveguide design that plays nice from 1KHz to 15KHz.

Again, Im not against line arrays. They can be incredible performers but they have to be good.


Again, I think the point of this discussion is to point out that 99% of those "nice and small" speaker built these days do not cut the mustard for true performance. You can say the speakers with < 8" woofers sound nice but when remotely pushed they are going to puke up huge distortion.

Size went small for the WAF effect, engineering tried to do their best with xmax on some but still its just almost impossible to keep something small and have high SPL/Low distortion.

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post #20 of 152 Old 02-27-2010, 08:09 AM
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Originally Posted by Timothy91 View Post

Remember that with bass frequencies, for a 6.5" driver to perform up to an 8" driver, it must move equal amounts of air with it's cone. What is the only way to do that? Design a motor and surround for deeper xmax so it can have a longer 'throw'. What happens as a result? You need more amplifier power to move that bigger motor in and out enough times to duplicate the output of that 8-inch driver. That's a lot of extra engineering just to make up for a slightly different cone size and it's STILL less efficient than the 8-inch woofer at 80Hz and needs real good engineering to keep have the same distortion performance as a lesser 8-inch.

So, when comparing even close to similarly designed 6.5's and 8's, the 8's always win.

Oh, and here is the funniest FAIL of that link you posted:

So what is the catch? What did we trade to achieve all of these attributes? The answer is nothing...

Fs = 45.8HZ
Qes = 0.48
Qms = 6.37
Qts = 0.44
Vas = 9.61L
Sd = 131cm^2
Xmax = 12.5 mm one-way
Re = 6.4 Ohms
Le = 0.84 mH
BL = 10.79 N/A
Power: 125W Approx: No IEC testing conducted
Spl = 84.7 dB/1W/1M

FACEPALM!

You can PM Kevin Haskins about that if you like, he is a member and he built those drivers.

Again, they are incredible VALUE drivers for 8" woofers. The Xmax is sick for an 8" driver but they are not meant to be high SPL drivers compared to B&C, JBL or Lambda choices.

Btw, I own 6 of those 6.5" woofers, they have an incredible value for some applications.

Now that brings me to the last point. I said before that 2 channel critical listening at low SPL levels need not apply to this discussion meaning that EVERY driver has a specific application that its intended for and if someone wants high SPL/low distortion designs they need to look past what most companies offer. designs like JTRs and Seaton Catalysts/Sparks are going to be very popular for years to come when everyone realizes that we need high sensitivity, high SPL headroom to get the best HT performance.

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post #21 of 152 Old 02-27-2010, 08:11 AM
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Originally Posted by Timothy91 View Post


Here is a pro 18" subwoofer:


Nominal Diameter: 380 mm (15 in)
Rated Impedance: 4 ohms (G)
8 ohms (H)
16 ohms (J)
Power Capacity1: 600 W AES continuous pink noise
Sensitivity: 97 dB SPL, 1 W, 1 m
Frequency Range3: 30 Hz 2.5 kHz
Power Compression4:
at - 10 dB power (60 W): 0.7 dB
at - 3 dB power (300 W): 2.5 dB
at rated power (600 W): 4.6 dB

I don't think professionals will be using 6.5's anytime soon, no matter how well engineered they are.

YOu should know that MJG100 already knows all about pro drivers, etc.

Professionals are not building critical listening systems much either....just to point out that its not all "one side is right and the other side is wrong". Each has their specific application.

Sensitivity is important IMO but it doesnt matter how sensitive the driver is if it measures like crap.

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Originally Posted by aboroth00 View Post

I think i get what penn is getting at. I believe he's talking about a high spl application with HUGE dynamics such that ranges well above 100db in which bigger woofers are better suited to do the job. In this case I agree with penn. However, in my applications in my humble theater, i rarely push 95db and maybe when i'm feeling adventurous i wonder around further than 100db (maybe).

I'm sure he will agree that in a less taxing situation an equal cone size of 5.25" drivers relative to 8" drivers which are similar will yield similar results. There is one caveat of having larger drivers and thus large dynamics. You need a good high range driver which you can cross lower to your larger driver. But if you're listening at ear splitting SPLs I doubt you'll be paying attention to the mids, but instead be holding on for dear life as I'm sure penn does when he cranks his system

However, if i want large dynamics, a large room in which bass can propagate, I'll stick to the local IMAX; I simply can't afford all those drivers unfortunately

Great points but even if you push > 85dB you should be aware that if you are 12 feet back and you have dynamics of > 20dB you will need drivers that actually can hit 120dBs.

Its all about the headroom and dynamics and not really about what our SPL is. My SPL is average below 85dB actually but I still perfer speakers that can play up past 115dB. I like it because I have the speaker headroom plus I do not need to worry about having 500W amps which would be required to properly hit the peaks without distortion. I like lightweight < 100W amps actually since I tend to move them around and test, and play, and tweak.....

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Originally Posted by penngray View Post

YOu should know that MJG100 already knows all about pro drivers, etc.

Professionals are not building critical listening systems much either....just to point out that its not all "one side is right and the other side is wrong". Each has their specific application.

Sensitivity is important IMO but it doesnt matter how sensitive the driver is if it measures like crap.

For bass frequencies, you won't hear the difference with the driver, only the enclosure. The human ear is not sensitive to bass distortion, so you can buy 'pro' audio drivers for the bass and then buy standard hifi drivers for the more critical frequencies. I'm a BIG proponent of the idea that you over-do-it on the intended SPL of your low frequencies because the less a speaker has to stress to produce that given sound, the more effortless it sounds and the more the amp can punch out (doubling of power with lower ohm loads due to speaker's demands with certain moments) and the more headroom the woofer has for punching out those peaks without power compression. Bass frequencies need large drivers to sound best. The biggest enemy of dynamic bass output and high SPL levels isn't "distortion" (especially for long operating times) it's power compression. Large woofer + large enclosure = Damn fine bass. And the funny thing is that you don't need the most powerful amplifier in the world to drive large high efficiency woofers to loud levels. They use every watt to a great potential.
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Originally Posted by Timothy91 View Post

So, when comparing even close to similarly designed 6.5's and 8's, the 8's always win.

Oh, and here is the funniest FAIL of that link you posted:.

And that's the ball game folks. Once you go from theory to actual products, threads seem to turn into a train wreck.

Let me add anecdotal evidence.
My infinity beta-20's with their 6.5" driver and subwoofer sound better to me than my Beta-50 with their twin 8's and subwoofer. But it has nothing to do with bass or midbass, but instead midrange and lower treble.

YID DIY
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post #25 of 152 Old 02-27-2010, 08:39 AM
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Originally Posted by Timothy91 View Post

For bass frequencies, you won't hear the difference with the driver, only the enclosure. The human ear is not sensitive to bass distortion, so you can buy 'pro' audio drivers for the bass and then buy standard hifi drivers for the more critical frequencies.

I wouldnt mix and match pro audio drivers with standard hifi drivers unless you are using an active crossover since you have to pad the pro audio drivers down the the hifi driver sensitivity levels anyways. I do not have to pad my DIY speakers at all since I use a DCX and amps to alter the gain per driver.

The critical frequencies are really from 600Hz to 2500Hz also since that is the range of most voices. You are still in the range of the main woofer. I agree that we are less sensitive to bass distortion at the lower frequencies but there is still high performance value in the 300Hz and above region.

Also, I never meant to say the hifi driver is better then the pro audio driver in any aspect. Great thread on that topic is found here http://www.diyaudio.com/forums/multi...pros-cons.html.

I have not seen measurements showing hifi drivers being better the pro audio drivers.

Even for the smaller drivers I would pick the a 6.5" driver from B&C, PHL or 18sound over scanspeak stuff.

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Originally Posted by Timothy91 View Post

Lets do the math:

84db SPL at 1-watt
add a 2nd driver = 87db at 1-watt (for each driver, 2-watts total)
add a 3rd driver = 90db at 1-watt (for each driver, 3-watts total)
add a 4th driver = 93db at 1-watt (for each driver, 4-watts total)
add a 5th driver = 96db at 1-watt (for each driver, 5-watts total)

You may want to REdo the math...Not even close to being right.

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Originally Posted by Timothy91 View Post

Here is a pro 18" subwoofer:

Sensitivity: 97 dB SPL, 1 W, 1 m

And that driver is about useless below 40hz. That's how pro-drivers work. High sensitivity, aweful low end bass. The lower you want your bass, the more sensitivity you must sacrifice.

YID DIY
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post #27 of 152 Old 02-27-2010, 08:58 AM - Thread Starter
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Originally Posted by penngray View Post

I wouldnt mix and match pro audio drivers with standard hifi drivers unless you are using an active crossover since you have to pad the pro audio drivers down the the hifi driver sensitivity levels anyways. I do not have to pad my DIY speakers at all since I use a DCX and amps to alter the gain per driver.

No no. I meant to use the pro audio driver as a subwoofer application, not a midbass app. The lowest frequencies need lots of additional headroom to be at their most destructive.

I was using pro audio drivers to show my point that you can't substitute a smaller driver for a larger one. You can get in the ballpark of an 8-inch midbass focused woofer with dual 6.5's, but it's still not as good as just using an 8-inch driver and the 8-inch driver takes up less room on the front baffle than two 6.5's. That was my main point and I feel I've effectively shown it so that anyone reading can understand with great clarity with no ambivalence or illusions. It's black and white. There is NO middle ground. There are ways to 'cheat' or 'trick' a little bit more bass out of a smaller speaker (like with enclosures that exaggerate a small set of bass frequencies like what you see in car audio or add more drivers or design a driver with more xmax, etc) but ultimately a larger speaker does bass better and louder with less watts, period.

Quote:
The critical frequencies are really from 600Hz to 2500Hz also since that is the range of most voices. You are still in the range of the main woofer. I agree that we are less sensitive to bass distortion at the lower frequencies but there is still high performance value in the 300Hz and above region.

I've found in my EQ experiments that there is a range in the midbass region that lends proper balance to the mids so that they sound correct. Take any 1/3rd octave 10-band EQ. Listen for vocal clarity and mix separation with the EQ flat, now adjust 125Hz and 250Hz down -3db. The mix on most music when played on most setups suddenly sounds cleaner and more defined. I don't know why that is but it's true. I think it's due to the auditory masking effect. Nearby frequencies are being masked by loud midbass. This EQ adjustment will not work on all recorded material, just a lot of them.

Quote:
Also, I never meant to say the hifi driver is better then the pro audio driver in any aspect. Great thread on that topic is found here http://www.diyaudio.com/forums/multi...pros-cons.html.

I have not seen measurements showing hifi drivers being better the pro audio drivers.

Even for the smaller drivers I would pick the a 6.5" driver from B&C, PHL or 18sound over scanspeak stuff.

The only way to know for sure is to volume match the drivers, put them in an ideal designed enclosure and compare them in an ABX test with trained listeners. That should tell the story. I have no doubt that at loud outputs in a large/treated room (like 25'x25'), those pro drivers should sound better due to better power compression specs and great sensitivity.
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Originally Posted by Timothy91 View Post

No no. I meant to use the pro audio driver as a subwoofer application, not a midbass app. The lowest frequencies need lots of additional headroom to be at their most destructive.

Those pro-audio woofers are not good for subwoofer useage. They have light cones which is great for reaching into the midrange area and also allows them to have a high sensitivity (less weight is easier to move). They can also dip into music bass (35+hz) but "subwoofer" below 20hz use they don't work at all. No xmax and too high of an fs.

Here's a 21" subwoofer, check out it's specs.
Fs: 16.3 Hz
Le: 4.0mH
Re: 3.8 Ohms (Voice Coils wired in series)
Qms: 3.38
Qes: .44
Qts: 0.42
Mms: 527g
Cms: 0.18 mm/N
Vas: 605L
Sd: 1550 cm^2
BL: 21.5
X-max: 32mm
Pmax: 1500W
SPL: 89.6 db/1W/1M
Notice anything?

YID DIY
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post #29 of 152 Old 02-27-2010, 09:11 AM
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Originally Posted by Timothy91 View Post

No no. I meant to use the pro audio driver as a subwoofer application, not a midbass app. The lowest frequencies need lots of additional headroom to be at their most destructive.

Ah none of this discussion is about subwoofers actually, not when you are harping about 5.25" drivers.

As for the pro audio driver used in subwoofers...we have been through that debate already over on DIY. The problem with your pro driver is that it can not go very low. Its impossible to get both sensitivity and low frequencies. See what looneyboomer posted above. Fine for music down to 30Hz but who cares about that, we want < 15Hz performance for movies!!

On the other who cares about those woofers when you can have tapped horns doing incredible things with even lower efficiency horns. See DIY forum that latest craze!!


All these topics have been discussed at great lengths over on the DIY forum. You really are in the wrong forum to discuss them.

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post #30 of 152 Old 02-27-2010, 09:15 AM - Thread Starter
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Originally Posted by Looneybomber View Post

Those pro-audio woofers are not good for subwoofer useage. They have light cones which is great for reaching into the midrange area and also allows them to have a high sensitivity (less weight is easier to move). They can also dip into music bass (35+hz) but "subwoofer" below 20hz use they don't work at all. No xmax and too high of an fs.

Here's a 21" subwoofer, check out it's specs.
Fs: 16.3 Hz
Le: 4.0mH
Re: 3.8 Ohms (Voice Coils wired in series)
Qms: 3.38
Qes: .44
Qts: 0.42
Mms: 527g
Cms: 0.18 mm/N
Vas: 605L
Sd: 1550 cm^2
BL: 21.5
X-max: 32mm
Pmax: 1500W
SPL: 89.6 db/1W/1M
Notice anything?

Yes. I notice that xmax was added to focus the driver's efforts on moving more air for deeper bass, but at the cost of efficiency. There is always a tradeoff.

On the pro audio driver there is still some usable sound below 25Hz when you are "cranking" the volume (and with bass under 25Hz, you MUST have the volume cranked up because it takes lots of power to produce enough SPL to make 25Hz audible and to make 20Hz be 'felt'). If you wanted, you could grab an EQ and reduce all the bands above 25Hz and force the pro driver to produce more of the inaudible "shake/impact bass" but I think there is plenty of bass and impact that is felt in the audible frequency range which is all you need. I think bass under 25Hz at high SPLs will cost major $$$, high amplification and give virtually no real benefit to the sound. That's just my opinion though. I guess some people want to 'feel' bass deeper than they can hear even though there is plenty of bass that is 'felt' above 25Hz. BTW, to get that sub you listed to hit 120db, you will need 1000-watts of amplification (and 20Hz & lower very likely aren't going to be the loudest frequencies produced), you will still need an equalizer to 'force' the sub to produce substantial sub-sonic bass.

It takes a lot of pain in the ass money and adjustment to do it right. All told, after the xmax sacrifice of that design and the 1,000-watts and the equalization to force more subsonic output, you STILL are going to end up with a sub that does about 115db SPL at 20Hz, but to match you'll also set 30Hz and 50Hz to do 115db. That's a LOT of money, gear and effort just to put 20Hz on the same level as 30Hz and 50Hz. I just don't see the point. Nobody is going to miss 20Hz when 30Hz to 50Hz is rocking with a tad of 25Hz rolled in at high output.
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