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Discussion Starter · #1 ·
I have an old 20+ year old "15 woofer Cerwin Vega Speaker that I am currently using with my Home Theater Set-up... to bring out the bass. I was just wondering what am I giving up by using that instead of one of those "Home Theater" Subwoofers... I am powering the speaker with a Peavey Amp and getting the "Bass Feed" from an TX SR500 Onkyo Receiver at 80hz crossover. I am running it at a very low level since it really was designed for running my piano keyboards at night clubs/auditoriums etcetera. Also where should the optimum placement be for such a speaker.... Right now I am "hiding it" if you can call it that behind one of my Infinity Quantum 3 Speakers.... I was thinking about moving it next to the Sofa, but am wondering what the impact would be.. My home theater room is in a basement with a room size about 14'7" by 10'5". I was originally running the Onkyo 8" subwoofer which came in the package at Circuit City called the TX 650 package??? Anyway when I changed from the Onkyo to the Old Cerwin Vega Speaker the change was "dramatic" I heard lows I have never heard before! It like goes into your body somehow....


Just want to hear what people think....
 

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Most "pro" bass cabinets are meant to get loud, and trade off low frequency extension for it. I would be suprised if your sub was flat to much below 55Hz. Being that you have it crossed over rather close to this point, you effectively will lower the cuttoff in room, and still have the ability to produce a good amount of bass. Is this cabinet vented or sealed?


I would guess you are missing out on a good deal of low end vs. what is possible, but very likely are much better served than the wimpy 8".


For say $400-800 you should be able to get a pretty serious sub, and maybe cheaper if you have an amp to drive a passive sub. Maybe a used SVS?


Regards,
 

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Discussion Starter · #3 ·
Is there a simple way to test how low a speaker can go? say 50 hz versus 55 hz? Some music diagnostic CD or so?


One thing I have noticed is that I can "punch" the bass to extreme levels, like at a "disco tech" by adjusting the gain, but I then drown out the high end trebel. I currently have it at a "balance" so I get all my high ends, but no real "punch" (low gain), but I think I really do hear some really low end sounds. The gunfire on the 5th element sounds in the diva scene I think go pretty low. I currently have the Trebel and Bass set to 0 on my receiver. Should I adjust that at all?


I am not sure what the difference is between sealed and open is, but I have a feeling it is open since you can clearly see the 15" woofer. It really is a heavy monster.
 

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Sealed means no ports or open chambers to the internal box. Vented means visable port or square chamber allowing air to move in and out of the box. Since it's a pro design, it's most likely a vented type box. Vented enclosures generally will yield a much more efficient output (more boom per watt of power), and this is why they're the preferred method for pro designs. As Mark pointed out above, pro subs typically sacrifice the lowest fundamental bass range for more efficiency, because efficiency is king in pro audio. This also explains why you sense so much more impact with this sub. Pro subs are generally very, very good home theater subs for this reason. Music like classical and lite jazz, however, are better served by something with more range. Most modern pro subs will easily reach into the high 30 - low 40hz range, but very seldom will dip into and beyond the low 30s. Sure, in home theater application, you're going to miss out on the lowest info, but what's there is typically pretty darn involving... ;)


Ps: one other common pro design is horn loaded - expanding chamber going out from recessed woofer. This is a sealed design in nature, but with horn loading to increase efficiency.
 

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Discussion Starter · #5 ·
Thanks for all your comments guys. Am I the only one using something like this for a subwoofer? Must not be too many keyboardists who were in bands and are now into home theater who hung on to their old stuff.... Based on all of your comments it seems that only frequency range is the difference....


I found some software on the net called NCH Tone Generator which works on a PC at various frequencies. I figure I will hook my PC up to my Receiver and see "how low can I go!" I wonder how much my sound card would impact the frequencies at all...


Anyway where do most people put the subwoofers? Since mine is basically a directional subwoofer, would it be a bad idea to put it next to the sofa?


Should I keep it where it is in the front of the room right behind the left and right Infinity Quantum 3 speakers that I am using...?


Would it be better if I placed it face down on 4x4 blocks of wood to mimic today's subwoofers or does that make no difference?




Any more input would be most helpful....


At what point in subwoofer quality would be better than my setup? Should I only consider 15" woofers which seem prohibitively expensive?
 

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Quote:
Originally posted by edwardr132
Thanks for all your comments guys. Am I the only one using something like this for a subwoofer? Must not be too many keyboardists who were in bands and are now into home theater who hung on to their old stuff.... Based on all of your comments it seems that only frequency range is the difference....
No, many have gone this route, but if the really low stuff is important, you'll need to look elsewhere for it.


Quote:
Originally posted by edwardr132
I found some software on the net called NCH Tone Generator which works on a PC at various frequencies. I figure I will hook my PC up to my Receiver and see "how low can I go!" I wonder how much my sound card would impact the frequencies at all...
The PC card will generally only add noise (THD) - not alter the frequencies.



Quote:
Originally posted by edwardr132
Anyway where do most people put the subwoofers? Since mine is basically a directional subwoofer, would it be a bad idea to put it next to the sofa?


Should I keep it where it is in the front of the room right behind the left and right Infinity Quantum 3 speakers that I am using...?


Would it be better if I placed it face down on 4x4 blocks of wood to mimic today's subwoofers or does that make no difference?


The best advice i can give is to try a few different locations and see what sounds best to you. Corner positioning for a horn loaded box will typically extend the low end response significantly. This "corner" loading will also help other types as well, but to a far lesser extent. Best guess says that your optimum location will come from being on same wall (or corner of wall) as front channels. Try that and compare to a corner near seating area. Use the same material over and over so you have some kind of constant. Incidentally, unless you are specifically sending this sub frequencies over around 150hz, it shouldn't be directional (other than intensity if you're sitting "right" next to it).



Quote:
Originally posted by edwardr132
At what point in subwoofer quality would be better than my setup? Should I only consider 15" woofers which seem prohibitively expensive?


Boy, that's a loaded question. Pretty much impossible to give a simple answer to, but you might do a little research using the forum search engine. Basically, as you discovered with that wimpy little 8"er, smallish subs don't work too well unless you're in a very small room. 10 and 12" subs are a dramatic step up in performance for the simple fact that they can move air far more efficiently. Most people really don't need more than what a decent 12" can do in an average sized room. Others (like me) are bass hungry lunatics and can't live with anything smaller than at least one 18" pro driver, or several 15". Also, there's the topic of speed and accuracy, not to mention freq response desired. Really big drivers tend to suffer more from a parameter called group delay. Put simply, they tend not to accelerate from dead stop to a given excursion, or change directions as rapidly as a smaller driver. Also, larger diaphrams tend to "flex" more than smaller, more rigid drivers, which results in increased intermodulation distortion. To offset these setbacks, the larger drivers don't need to move as far as smaller drivers to move the same amount of air, so you don't get into these issues right away, as they come into the picture as volume increases. Additionally, the human ear is far less sensitive to distortion and phase problems, et al, at really low (sub) frequencies as they are at mid and high frequencies. So, even though these problems are measurable, they're not as obvious to us as they would be in our satellite speakers. Confused yet ? :D Trust me, it goes on and on when discussing speaker technology. The short answer, is audition them until you find something you feel outperforms what you've already got.... ;)
 

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Discussion Starter · #7 ·
Thought I would post my results back on using the software: NCH Tone Generator. Frequencies are like notes on a keyboard with octaves and such. If you are familier with the notes, you can hear the notes... C, B, B flat, A, G, Gflat etcetera. The software lets you play from 1 to 13 notes at once all at different frequencies. The software also lets you increase the decibals of the note. I highly highly reccomend using the software to test your audio systems. I just can't recommend the software enough..... Is this news to you guys at all or just me waking up to smell the coffee?


I ran the software on my system and was pleasantly surprised. Believe it or not, I can get the woofer to go all the way down to 20hz!!!!!! The woofer is definately physically capable of reaching that limit. Realistically, At my current settings, of volume in keeping the bass and the treble in balance, I am hearing somewhere in the range of 35hz to 40hz. The lower notes are there, but very subtly, and mostly as vibration. Only when you crank up the volume do you hear the actual tone of the lower notes. I think based on this I guess that using an equalizer is an extremely critical tool where you would crank up the lowest of notes and bring down the bass level of the upper notes could in effect bring the system in balance. At the levels of sound required to get the lowest of notes, the bass notes at the higher end such as 60hz to 80hz brings in too much vibration for the room. This makes logical sense since the lowest notes are inherently harder to hear. You tend to feel the vibration and hear the notes very faintly. These are the notes that like go in your body as I was describing above......


I know one thing for sure. My 15" Cerwin Vega woofer was built extremely well. It can handle everything!!!!!!! I knew that when I added to my system around 20 years ago. The original Cerwin Vega woofer blew out within a few months of using it. That one was not well built. The one I am using is like a tank in terms of weight and construction. I bought it once from United Audio again about 20 years ago. I mentioned my problem to the manager there and he just happened to have a Pro Woofer that they don't sell. I remember him telling me that it would be extremely difficult for me to blow this one out based on its construction... and what its requirements were. Synthesizers can put a huge load on a woofer at the low end and this woofer has always done a great job for me.


As a side note, I was playing computer game called Beachhead with the bass turned up and man it was just getting too real...... When airplanes flew overhead, you really felt it. It was hard to shoot then...... and you hear the bullets coming at you. The explosions all around you... It was pretty intense. I never got that sensation just playing on my 21" monitor at my PC.......


The amazing thing is that for normal music and movies I have set my Peavey Amp/mixer to a level 1 and for cranked up bass to level 2 on the channel I am using. I am hardly using the amp at all. The main amp level is at a level 6 or so...


Do you guys use equalizers? Knowing all this information now would make it even harder for me to figure out just where my system compares to the audio subwoofers.... I still haven't played around with room placement yet. I think I will. I want that amp near me so I can adjust the Bass on the fly!!!!!
 

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Quote:
Originally posted by edwardr132
Thanks for all your comments guys. Am I the only one using something like this for a subwoofer? Based on all of your comments it seems that only frequency range is the difference....
There are a few of us out there. I'm using a 18" JBLPRO THX sub in my HT. Its a pretty large beast. I'm using an older, dual port version of the one shown.
http://www.jblpro.com/images/cinema/4645c.jpg


It can give flat response to 22 Hz. Needless to say, with a 99 db sensitivity and 1600 watt power capacity, it pumps out some serious deep bass. I'm feeding it 1200 watts and have never phased it.


That said, most pro subs don't do much below 30 to 40 Hz. IMO, 30 Hz would be OK for HT use, but not 40.
 

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Most pro woofers drop like a rock below 30-40 Hz, but some have deep extension. In my musician days (it's all a blur), I used four huge compression horn enclosures with Gauss 18" drivers, and they were pretty flat to 20 Hz. If you stood in front of one of our stacks during one of my tasteless stadium drum solos, they would knock you over.


The biggest problem with pro woofers and subwoofers is they are not designed to respond very much unless they are being kicked pretty hard. Often you're dealing with high moving-mass coupled with very stiff suspension components. At normal home listening levels, the driver may resist moving, and bass levels may measure very low...until you reach 100 dB or more. I've dragged enough pro speakers home to know they are not designed for moderate playback levels.
 

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Its like using a Mclaren F1 in the middle of traffic.:D Output for these types of systems are pretty decent above 40hz.Hardly flat, but it punches pretty hard.


Regards
 

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Quote:
Originally posted by goneten
Its like using a Mclaren F1 in the middle of traffic.:D Output for these types of systems are pretty decent above 40hz.Hardly flat, but it punches pretty hard.


Regards


I like your analogy, dude, however, wouldn't a more fitting one be a Hemi-Cuda (sorry, I'm partial to Mopars)? After all, an F1 is a finess machine that's also brutally powerful, while a Hemi-Cuda is just plain brutal - much like a pro sub... works ok most of the time, but when you really nail it, it lights up like canned fury released... :D
 

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Quote:
Originally posted by edwardr132


I ran the software on my system and was pleasantly surprised. Believe it or not, I can get the woofer to go all the way down to 20hz!!!!!! The woofer is definately physically capable of reaching that limit. Realistically, At my current settings, of volume in keeping the bass and the treble in balance, I am hearing somewhere in the range of 35hz to 40hz. The lower notes are there, but very subtly, and mostly as vibration. Only when you crank up the volume do you hear the actual tone of the lower notes. I think based on this I guess that using an equalizer is an extremely critical tool where you would crank up the lowest of notes and bring down the bass level of the upper notes could in effect bring the system in balance. At the levels of sound required to get the lowest of notes, the bass notes at the higher end such as 60hz to 80hz brings in too much vibration for the room. This makes logical sense since the lowest notes are inherently harder to hear. You tend to feel the vibration and hear the notes very faintly. These are the notes that like go in your body as I was describing above......



Careful there, partner... If you input a 5 HZ signal, you will see your woofer move in and out 5 times a second. However, that doesn't actually mean it will "do" 5 Hz. In actuality, when we say a sub like yours will only "do" down to around 30 - 50 hz, we mean with a reasonably flat response. Speaker boxes & drivers interact with each other as a pneumatic circuit which predicts a usable frequency passband of equal amplitude, and it's normal to see that "some" response exists wayyyy down there around 20 Hz, but (as you've already experienced) it's unusable because if you calibrate the bass at that frequency to sound "right" you will have an alarming amount of bass at higher frequencies within the designed passband of the woofer's usable response. Make sense? In other words, just being able to "hit" that 20 Hz note is useless - the woofer needs to have an equal amplitude at that frequncy as it does higher, say 60Hz, to be usable. Run that sweep again and note when you really notice the amplitude dropping off without touching the volume knob, and THAT will tell you where the usable low end is at.
 

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Hi M NEWMAN, its good to hear from you again.


Yeah, in actuality, almost all subwoofers can output incredible sound pressures down low.In a small closet and measured at the dustcap that is.:D


My computer speakers are rated down to 20hz, but we all know thats a load of bull.More like 70hz if I'm lucky.:D


Regards
 

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Quote:
My computer speakers are rated down to 20hz...
Would that be +0/-124 dB??


:D:D:D:D:D:D:D:D
 

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Discussion Starter · #16 ·
Update:


I have been able to completely blend in the Pro Bass 15" woofer with my system by +/- the front left. center and right speakers individually.



Can anybody recommend an equalizer to boost the lower frequencies and reduce the higher bass frequencies to get a better overall bass response?


I am assuming a Pro equalizer is the best choice? Yes/No.


One I am considering is the Behringer Ultra-Musical 31 band equalizer with settings at 20, 25, 31.5, 40, 50, 63 and 80 and lots more above 80 which I won't use since I am crossovering at 80hz. My plan is to boost the 20, 25, 31.5 and probably lower or keep the 40,50,63, and 80 either neutral or flatter.


What does anybody think about this equalizer? Will it work?
 

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Nothing wrong with using an eq on a sub. Most powered subs use some eq. The Behringer will probably work fine. Just hope you don't get any ground loops when interfacing pro with consumer gear. I'm using a Ashley 31 band, 1/3 octave eq and it has all the control I need. However, boosting the output much below the tunning of the port can very easily overdrive the woofer. Make sure you use a subsonic filter as well.
 
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