Subwoofer for music design assistance requested. Subwoofer recommendations welcome as well. - AVS Forum
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post #1 of 39 Old 10-19-2013, 08:17 AM - Thread Starter
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As the thread title states, I am looking to build a subwoofer system, that incorporates high efficiency subwoofers with the primary focus on music reproduction. I initially wanted a subwoofer with low frequency extension for home theater use, but also suitable for music, but my recent experiences always wanted me wanting more for music(not more output, should say better sound). So I have come to the conclusion that I will enjoy a system with musical fidelity over a system that would have low frequency extension for home theater use. I do have a few dilemas that I need to adress however.

First off, a target design. I do not know how much low frequency response I really should be concerned about. I know I want a overall flat response, but where would a good -3dB for a music system, and what about -10dB. With a sealed system, I may get a high -3dB point, but since it has such a shallow roll off the -10dB would be much higher than with a vented system with a low -3dB and a high rate of roll off in the low end end.

This is where I cannot make up my mind. I could do the vented, have higher efficiency, shallow roll off in the low end and limited EQ abbilites in the low end, OR a sealed system with slightly lower efficiency, a shallow roll off and a better ability to EQ the low end and not run into mechanical issues. This is where I am reaching out to the online community, whom have more combined experience than I could ever hope for.

So here are the givens.

-I plan to do a set of subwoofers.
-They will be powered off a Crown XTi1002 with internal DSP
-I am using Tannoy i8 for my mains. Decently efficient with limited low end. May be suitable to use a higher crossover point.
-The room is not huge by any means, but I do not plan staying here forever.
-Size isn't a huge issue for me, but practical.
-I am open to any configurations. 8"-18" single or multiple woofer formats.
-I initially planned to spend around $500 for the raw drivers, but I could come up with the extra money if the design justified it.

This is my overall goal : A set of subwoofers that produces musical bass with enough extension for most music, with decent-good efficiency so when I want to crank it, I can really crank it!

The biggest determining factor in choosing a subwoofer is how well it meets my design goals when I figure out those design goals.

Thanks with all any any help. I will do my best to post responses in a timely manner to keep this thread rolling.biggrin.gif
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post #2 of 39 Old 10-19-2013, 08:26 AM
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how loud do you play it? medium loud...dance club loud...deafening loud?

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post #3 of 39 Old 10-19-2013, 08:50 AM
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i'm running out of steam today, so i'll just put forward a suggestion and then we can discuss it further or folks can pound on it...

two 18" high sensitivity woofers, in large enclosures 8-10 cubic feet, tuned to something in the low 20's, and crossed into the "mains" at around 200hz or so. so, they need to be mid-woofers, not subwoofers.

first choice is probably aetd18h+, but it is pricey. second set would be jbl 2242, 18sounds 18lw2400, or something along those lines. jbl has gone wild with pricing so it might be out unless you consider used. might want 4 ohm drivers too to get the most power from your amp. we'll have to consider that.

as for spectral content...a search on "frequency range instruments" in google images will pull up a whole bunch of charts showing different instruments and their ranges. most music, even deep music, rolls off quite rapidly below about 30hz. really not much going on down towards 20hz, on average.

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post #4 of 39 Old 10-19-2013, 09:27 AM - Thread Starter
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Medium loud I would say. I have looked at the JBL and the AE td18h+ as well as some other JBL(do not remember) and E/V (evx-180b) drivers. Heard of the 18sounds, but never really looked into it. On second thought, with any of these drivers, I may not need a second woofer. I was initially thinking two subwoofers for more uniform coverage.

My only concern with what you said is crossing any of those woofers around 200hz. I would have to check if my receiver has the processing capabilities. Otherwise, I have an older processor sitting around I could use for the mains, but at that point, I would need amplification as well. And If I crossover that high, would I have to necessarily do a set, or would the localization below 200hz not be an issue for stereo sound?
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post #5 of 39 Old 10-19-2013, 09:42 AM
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18lw2400 is 18sounds answer to the jbl 2242. one nice thing is that it is available in 4ohm and the street price is $330 delivered.

200hz isn't set in stone or anything. wherever you can cross, you can cross. at 200, you probably want to keep it stereo. 150 is borderline. 100hz can be mono-summed.

which avr do you have?

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post #6 of 39 Old 10-19-2013, 09:49 AM - Thread Starter
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I am running a Onkyo NR-818. As for the processor, I think we have a used Crown UMS810 at my work shop, but like I said, I would need additional amplification. Might have some used amps sitting around too tongue.gif.

My biggest concern is localization with a "higher than I am used to" crossover point". It's been a while since I have even needed to take that into consideration.

How does the TD18h+ work into that category. Similar, superior, inferior? I have always been impressed with AE drivers and I like the fact that they are manufactured relatively local to where I am(support your local economy somewhat). On a side note, what does the letter in all the TD drivers indicate? There is the H, X,S andsomething else I think. If anyone knows
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post #7 of 39 Old 10-19-2013, 10:11 AM
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"My biggest concern is localization with a "higher than I am used to" crossover point". It's been a while since I have even needed to take that into consideration."

if you locate the subs next to the speakers, localization isn't a problem. maybe i'm not understanding what you are getting at.

the 18 is only available in h+ as far as i'm aware. i think it would have the edge but depending on how high you intend to run, that edge may be pretty small.

the h, x, and s are just different combinations of coil materials and surround parts to provide drivers more optimized for different applications. s is designed for sealed cabs for example. x likes bigger cabs, but offers more sensitivity in them. h is kind of like x, but trades off some sensitivity for working in smaller enclosure. iirc on all that.

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post #8 of 39 Old 10-19-2013, 10:36 AM - Thread Starter
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My localization question is pertaining to if I decided to use a single woofer and fed a mono signal to the speaker 200hz and down and placed next to one of the speakers. And I would play with placement as well. The subs may not go directly next to the speaker depending on coverage so there are minimal areas with "hotspots".

Playing with a couple designs right now. Found a speaker that models really well but have to compare it to a TD18h+ and the 18 sounds.
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post #9 of 39 Old 10-19-2013, 11:13 AM
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i don't think that there is a real clear answer to that one, but the lower in level that you max out at, the lower the crossover point that you can get away with with your mains. i just picked 200hz as a conservative number from a maximum blasting perspective. with medium blasting, 100hz should be fine. you'll just have to experiment and see what you like best.

and the modeling is only one step. there are a whole bunch of other things that make or break drivers or two drivers that model the same in winisd wouldn't have one cost $125 and the other cost $350 (except jbl kooky prices). shorting rings, cooling, flat wound voice coil wire, inductance control, power compression, etc. none of it really shows up in winisd.

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post #10 of 39 Old 10-19-2013, 11:24 AM - Thread Starter
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Very Valid point. I am looking all in the same price point. Going to get an Idea how they model and then compare on a more detailed basis.

The JBL and 18sounds model out almost identical. The JBL was a little better in afew categories, but not 3x the price better.

Is anyone familiar with FaitalPRO. Their 18FH500 models out pretty well, but is a lower power handling woofer when compared to the JBL or 18sounds. That is the only thing that scares me is 600W power handling. Would require a larger enclosure as well. IT's all a game of trade offs at this point.
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post #11 of 39 Old 10-19-2013, 11:29 AM
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power ratings sometimes are goofy too. make sure it is apples to apples and are comparing what you actually need. aes is a torture test. program is double aes and closer to how to think about what the driver can take. peak is 2x program and is risky business.

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post #12 of 39 Old 10-19-2013, 11:32 AM
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the faital pro driver looks pretty nice on paper. the only problem is that i'm not sure that i believe faital pro paper. :-)

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post #13 of 39 Old 10-19-2013, 11:40 AM - Thread Starter
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I did a quick Google search on the mentioned speakers, and the Parts express forum turned up some results. The guy bought a pair, and said the QC must be great there because of how well the T/S parameters matched to spec sheet. That's the only reason I considered it. Both were damn near identical to each other as well as to specs on paper. That is one case though. Not a whole lot else out there besides that one post though.

Playing with some B&C drivers right now. The 18TBW100 Models better low end, but has higher inductance so it starts rolling off much sooner than the FaitalPRO. But for what I need to do, not a problem I guess. Plus I know the B&C name.
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post #14 of 39 Old 10-19-2013, 12:37 PM
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winisd doesn't model inductance properly. another one of those limitations.

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post #15 of 39 Old 10-19-2013, 12:40 PM
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"But for what I need to do, not a problem I guess."

it is actually really high. normalized inductance is what you want to look at le/re. lower is better. 0.3 or less is about where you want to be. that is where something like the td18h really shines.

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post #16 of 39 Old 10-19-2013, 06:26 PM - Thread Starter
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Hmmmm. I am using Bassbox Pro6 for modeling. No idea if the inductance modeling is accurate however. Any experience anyone?

The TD18H+ is definitely still in the running. I know that is a big selling point on those woofers is the fact that it is so low, bringing distortion down even more because of it. Plus the AE speakers are more aesthetically pleasing if that's a selling point at all :P
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post #17 of 39 Old 10-19-2013, 08:57 PM
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inductance is complex and its effects are frequency dependent. to the best of my knowledge, all modeling programs consider the 1khz value and then just use that. so, actual rolloff does not match model. that's just asking a little more from the tool than it is capable of doing. almost all the drivers on your list, except maybe the 180b, will model very similarly in winisd and you can see why a suggestion of 8 cubic feet or so tuned to 22-25hz or so makes some sense. the model is also 2pi space, which is like outdoor measurement. room gain will increase what you actually get. meyer sound, jbl, qsc, all have a flavor of what you are talking about and they all use drivers that you are looking at in cabs of about the size and tuning that I mention.

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post #18 of 39 Old 10-19-2013, 09:34 PM
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Are you deadset on using the crown xti 1k? Its somewhat low powered, and I have not read very many positive reviews on its usage for subs ( I own a 2k, and a 4002, and am semi pleased with them).

the real question is how low you REALLY want to go. and how much space you are willing to sacrifice to achieve these goals. Since you didnt mention horns, I wont delve into them, it seems you want either a sealed sub or a vented sub system

I am not at all happy with the 2 ohm capabilities of the crown xti 2k or 4002, so I would not plan on running high duty cycle music with a 2 ohm load per channel, OR a 4 ohm bridged output. Considering you only have 500 watts available per channel at 4 ohms, extremely hi xmax is not extremely necessary. 4 cheaper, 8 ohm 18" drivers could do the ticket for a banging music system, with the crown xti 2 1000 as the power. the only downside to this configuration is you are going to be using a large amount space, about 7.5 cubic feet per driver.

with 4 Dayton Audio PA460-8 in 7.5 cubic feet per enclosure, ported, you should be able to hit 130 db at 40hz, with a -3dB point around 32 to 33 hz, with a steep hipass at 25hz, and a voltage limit somewhere around 30 to 33 volts. you could also just do 2 if you'd like, and save money, at the expense of Six db.

smaller boxes are possible, but may require more power than you have available to hit that mark.
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post #19 of 39 Old 10-19-2013, 11:15 PM
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that dayton driver uses a smallish magnet (which is less expensive of course) and so doubled up on the coil in order to bring bl up to where it needs to be. the cost in performance of that approach is increased inductance. the advantage is reduced cost.

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post #20 of 39 Old 10-20-2013, 08:42 AM
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if the drivers being discussed are too expensive, then the next best option would probably be something like the b&c 18ps76. not world class, but not a bad woofer. that and the 500 watt plate amp which is on special price now at parts express would make a good combo in a cab about 7 cubic feet or so tuned to around 26-28hz or so. it has built in eq for something like that too. it would give about 120db potential before room gain and that's nothing to sneeze at. the driver is out of stock though.

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post #21 of 39 Old 10-20-2013, 10:39 AM - Thread Starter
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Thanks very much for the help so far.

The price range is fine for the subwoofers. I am just trying to keep my options wide open so I may achieve the best possible performance.

I did notice many of the drivers I looked at modeled very similar. I threw in some other random drivers to see how they would compare. The TC Pro5100 looked pretty poor in comparison to most other drivers I plugged in. I do realize that a program like WINisd and Bassbox model in an open environment, but I would rather have too much output after room gain and eq out than have too little after room gain and have to boost.

LTD02, you gave me an easy formula to plug values into to give me normalized induction. I understand that lower inductance is better than high inductance as far as high frequency response goes, but what will normalized induction tell me as far as driver performance?

And Badman, I am using the Crown XTi1002 because I already own it. I bought it with the power needs of the time. It should be sufficient for what I need to do right now, and the built in DSP has it's advantages.
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post #22 of 39 Old 10-20-2013, 10:55 AM
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LTD, I heavily considered recomending that b&c 18ps76 to him as well, but parts express only has it available in an 8 ohm configuration. considering he is deadset on the xti 1002 amp for power, this leaves him with 250 watts.

thus, I recomended the daytons. he can buy 4 for less than his 500 dollar mark spend on drivers, and the xti1000 will drive them to xmax, the only downside is he ends up with 30 cubic feet of boxes.

another design to consideration if 30 cubic feet is TOO much, is a ported lab 15 design. its much smaller, about 3.5 cubic feet, and is only marginally less sensitive. Benefit is it will take considerably more power, but the xti 1002 is really only good for about 45. heres some pics.

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post #23 of 39 Old 10-20-2013, 11:43 AM - Thread Starter
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The XTi is a bridgable amplifier. It will output 1000W bridged @ 8 ohms and 1400W bridged @ 4 ohms. That is how I am planning to run the sub or subs.
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post #24 of 39 Old 10-20-2013, 11:46 AM
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Badman.

What software it that you are using? Doesn't look familiar to me. Does it have any advantages to UNIBOX or similar modeling software?
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post #25 of 39 Old 10-20-2013, 11:56 AM
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Read my post regarding the xti series. I personally have not found them to enjoy running below 4 ohms (stereo) AT ALL for sub use (this means they will likely not enjoy running 4 ohm bridge at all, although I've not needed to test it). for instance, my crown xti 4002, limited to 50 volts (down from 74 volts volts that the xti 4002 is capable of unlimited) runs around 50 degrees celsius when running 2 subs per channel (4 ohm load) when pushed within 3 db of that voltage limit. Hook up one more sub per channel, and a 54 second section of a track with high duty cycle (driven within 3 db of that 50 volt limit) will skyrocket the temperature up to 73 degree C (thermal happens at 75, found that out real quick). This is with the fans set to FULL SPEED in a room with ambient temp around 77 degrees Fahrenheit, unracked.

Bridging is fine for Hometheater, givin the high dynamic range (>20 db) of the source content, but most music now adays (esp electronic music, which is the only thing really needing sub 40 response) has a very low dynamic range, esp once you lopass the signal and send it to the subs (4 to 7 db for electronic music).

Edit. I'm using hornresp. Its primary design function isnt ported or sealed boxes, but it does them just fine. I really like it after the addition of the sliders in the loudspeaker wizard. I wish it showed combined response (and not just output from the port) before calculating and goign to the spl graph though.

I have eminence designer as well, but I find myself just going to horn response all the time because of the fiter wizard, which gives you a better idea of final response after protective processing is in place.

EDIT2

I should add that the volume numbers I quoted are for EACH driver, and include the port
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post #26 of 39 Old 10-20-2013, 12:20 PM - Thread Starter
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I see what you are saying. I have ran bridged @ 8 ohms before with no issues. Maybe with your recommendations, I will not run my Crown into 4 ohms bridges.

I played with the B&C 18PS76 and it looked like a good driver. Price point is good as well.
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post #27 of 39 Old 10-20-2013, 01:00 PM
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Thanks Badman.

Looks like theres a bit of a learning curve. I like to model with filters as well and that is a bit cumbersome in UNIBOX. Looks impressive for a freeware tool i must say, so i will give it a go.
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post #28 of 39 Old 10-20-2013, 01:10 PM
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the b&c 18ps76 does model well in an 8 cubic foot box, with a considerable increase in sensitivity below 40hz (down to 30hz) over the dayton and a bit more power handling. The xti 1k should still be able to drive it to xmax in an enclosure of this size, well before its rated power (so at least you dont need to worry about power compression really). It is still a pair of 8 cubic foot enclosures though... which can be daunting for some looking for music playback. The Lab15 ported box is still on the table as a smaller alternative, although it does beg for more power than the xti1k can provide, (it will take roughly 60 volts into the lab15 ported boxes to provide the same spl as the ps76 ported boxes with 40 volts, in 1/3 the space)






Splotten there is a good tutorail for horn respons here HornResp for DUM.... hmm, everyonel

A bit has changed since then, and there are some things that are not explained there, but you can figure them out, and if not there are plenty of knowledable people on this forum and many others who can pitch in. I prefer method 2 for ported designs because this allows you to change the actual shape of the port to your liking (rather than being a straight tube or slot). Honestly, I just find Hornresp more *fun* than any other modelling software lol biggrin.gif
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post #29 of 39 Old 10-20-2013, 02:35 PM
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Quote:
Originally Posted by todd.brust View Post

I know I want a overall flat response, but where would a good -3dB for a music system, and what about -10dB. With a sealed system, I may get a high -3dB point.

I'm 95% music, and ALL of my speakers and subs are now sealed.

Here's what I get...

Mains @ LP


Mains + Subwoofers + kick bins @ LP


6db hot at 2hz, and my -3db is 5hz.
Just because you are running sealed doesn't necessarily mean you will have a high -3db point, or that you would be limited to only that. It depends on your electronics and amps, and if you have boost applied to the infrasonic range (which I do).
Note though: I don't have any boost applied above 20hz, I'm just running them in accordance to the subwoofers normal operating-abilities and within the amplifiers limits.

I'm running more than 8 18's, and even then, I still find that 110 to 200hz is highly localizable (if ran any hotter than I have it, in my rig at least).
But having a pair of subs up front will definitely help compared to just a single unit; especially if you have stereo bass, such as me.
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post #30 of 39 Old 10-20-2013, 04:20 PM
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le/re is a measure of the normalized inductance. when a coil is powered in a magnet field, current moves in the coil. that current creates a magnet field of its own, which is opposite to the field of the driver. so the more power that you send through the driver in order to get it to move, the more resistance the driver creates against itself in the process. kind of like stomping on the brake and the gas while driving a car. one effect is high frequency rolloff and reduced high end sensitivity. another is increase in distortion, particularly intermodulation distortion. as a practical matter, it simply means the driver won't sound as "clear". in the grand scheme, there are many fish to fry before getting to normalized inductance and the lower your crossover point, the less that it matters, some would even go as far to say that it doesn't matter.

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