Would a True Sub 10" long-throw better than 15"

[pate]

I wanted to know if these little subs,SVS,HSU out perform the 15" and 18" subs.The brand that I am comparing to or MFW-15 350 watts and the Cerwin-Vega CVA-118 18" 700 watts.THX

[Mr Peabody]

The answer will inevitably ly with some one who is familiar with these brands which I am not. With all things being equal, and in general, a 15 or 18 will move more air and should be able to play lower frequencies, this may be more desirable for home theater. If you also listen to music a 10" should have a faster response which would be more desirable. A lot of the performance from a sub will rely more on the quality of amp and driver than actual speaker size. So it is possible for over all performance of a 10" sub to be better than a 15".

[Sir Terrence the Terrible]

I seriously doubt that any 10" subwoofer of HSU or SVS will outperform that 18" Cerwin Vega, but the HSU and SVS subwoofers are very competent subwoofers nonetheless.

I would audition them all(I know HSU and SVS have an audtioning period you could ask about) and hear which actually does well IN YOUR ROOM. You may find the 18" CV an overkill, and a HSU or SVS just the ticket. Or you just may enjoy the power that the 18" brings to the table.

[RoadRunner6]

That CV sub is a pro sub, designed for bands, etc. it does not go down very much below 35Hz or so but plays extremely loud. It is not for HT use. The 123AV MFW-15 is a new model and I haven't seen any pro reviews but first looks sound very encouraging.

Not sure what you mean by a "true" sub. Can you explain?

The better of the HSU and SVS models will probably outperpform the others, especially the "turbo" model from HSU and the top cylindrical and top box subs from SVS.

Where do you get "little" subs from HSU and SVS. Are you talking about the small cube style models sometimes called mini subs like the SVS SB-12 Plus or do you mean any sub with a 10' driver. Please be more specific if you want better answers. What us the sub for, movies, music, both and what size room and other speakers.

RR6

[pate]

My room is 13x21x8 and I had two M&K 5000thx subs in there.I went on vacation for three weeks,and had water damage to all of my speakers.I will just use this room for action movies only.I have to start over,so what money is left over,I can buy what I want.Most likely it will be a bose sys.and 12inch black and white tv.THX Again

[02audionoob]

Personal preference here, but...I'd concentrate on putting together speakers that sound great to you...and those might be a brand less famous than Bose. Of the brands you see at the local Fry's store...Bose, JBL, Polk, Infinity, etc...Bose is only mid-pack at any particular price point. And for a sub...as has already been stated, the Cerwin-Vega is about being loud. In fact, Cerwin-Vega is about being loud, in general...considering their website calls them The LOUD Speaker Company. I would be more likely to prefer what you're calling the little sub unless you're just looking to be overwhelmed by the effects in the movies.

[kexodusc]

If you also listen to music a 10" should have a faster response which would be more desirable. A lot of the performance from a sub will rely more on the quality of amp and driver than actual speaker size. So it is possible for over all performance of a 10" sub to be better than a 15".
I almost completely agree with what the good Mr. Peabody said.

A word on the 10" woofer having faster response. If the two woofers in question are of equivalent design quality, all things equal, tthe 15" or 18" should be even faster.

This is a common misunderstanding in the audio world, and I think it has more to do with the 1980's and 1990's and the poor availability of capable subs in the larger sizes, and to some extent the poor transient response of ported cabinets the lower the frequency (so of course, bigger, lower playing woofers would sound less "fast"). Until HT took off, there weren't many around, and the ones that were there were expensive, and cheaply made! People probably heard the crappy big subs and assumed it was the size affecting woofer speed. After digital processing, I've seen nothing in the last 10 years advance as rapidly as subwoofer quality.

I can explain why a bigger sub will move even faster - 15" woofers do move a lot more air...consider the area of the cone is more than double, and larger woofers with bigger stronger motors generally are more efficient, ie, play louder per watt.

I'll take 2 woofers I have from Dayton's Quatro line a 10" and 15". To create an in room 90 dB (at 3 meters) 30 Hz tone, the 10" woofer requires 88 watts and excursion in a ported cabinet is 8.5 mm...this is understated a bit because the cabinet is tuned at 29Hz, the excursion of the woofer is relieved by the port "taking over".

The 15" woofer requires 23 watts and excursion is a mere 3.5mm, and note that the 25Hz is almost at the excursion peak (27Hz) in this box.

In sealed cabinets, I'd expect the differences to be even more slanted.

Long story short, that woofer is using way more juice and has to move almost 3 times the distance to do the same thing. For that 10" woofer to be faster, the motor is going to have to be very powerful, and will be a much more costly design. If the 15" had the same design, again, it would be better. A lot of those XBL^2 technologies, etc, floating around out there look to maximize woofer speed across larger excursions.

Adire Audio actually published a good research paper on this very subject a few years back.


One last comment - when comparing across brands, it's difficult to know which woofers are made with transient respone in mind - I still see some subs out there that are built for low Hz and high SPL, and a lot of smaller subs are faster still. Make sure you can demo whatever you're looking at.

[GMichael]

There's no replacement for displacement. (unless you are willing to spend much much more)

[Mr Peabody]

Kex, I'm not saying you are wrong, I'll have to look into this some more, but that's opposite to everything I've always been told by reps and sales staff. Your example makes sense. I have to wonder why high end speaker companies choose smaller drivers and almost no one uses 15" or 12" in home speakers any more. Dynaudio's Evidence Flagship only uses 8's, I'd think with a no money object speaker that they'd use the best size driver for the job. And, after spending over $100k I hope they weren't expecting some one to buy a sub. Trust me though, I heard the Evidence, they don't need a sub. Maybe it's not actually the speed that makes the smaller drivers sound more accurate. But there has to be some reason why manufacturers use smaller bass drivers, if it was true that the larger woofers were more accurate some one would definitely offer them as a pure quality alternative. Do you think the Dayton example is typical?

I hate to get off topic but this is interesting. If you have any links or anything I'd be interested in seeing them.

[kexodusc]

Kex, I'm not saying you are wrong, I'll have to look into this some more, but that's opposite to everything I've always been told by reps and sales staff. Your example makes sense.
You aren't alone here..even up until 2-3 years back I was of this opinion as well. In fact, my early posts here on subwoofer topics will often make such claims. I think Dr. Greene, Wooch, Sir T, etc all called me out on it at one point way back. I even downsized from a 12" sub to a 10" sub. I think in many commercial examples, the 10" subs just have stronger woofer motors than their 12" brothers, but when that's the case it's not a fair comparison - woofer size shouldn't be blamed...undersized motor design for the size of woofer should.

I'll go one step further...most 10" subs I owned were better musically than 12" subs I owned. How could I not arrive at that conclusion?

I do recall getting linked to the Adire research paper here that mathematically explained why size and mass are irrelevant. A boring read, but that was my first eye opener. I then started posting the question on other forums in the DIY community - it was pretty much unanimous. Woofer size doesn't affect transient response as much as excursion and motor design do. Motor design is critical. If the magnet is powerful enough and the voice coil inductance low enough, the woofer will move fast - if it's underpowered, it loses it's control the further the woofer moves out. Sealed cabinets also have big advantages here over ported cabinets

The Car audio and DIY guitar/bass amp communities have accepted and known this for quite some time...it's still taking time in the home audio community....Like I mentioned earlier - I think a lot opinions on subs were made back in the 80's and 90's when (by today's standards) subs were more expensive and not great performers. If people believe 15" woofers are worse sounding, they won't even ask a salesman to look at 15" woofers.
Sales staff aren't always in the know either.



I have to wonder why high end speaker companies choose smaller drivers and almost no one uses 15" or 12" in home speakers any more. Dynaudio's Evidence Flagship only uses 8's, I'd think with a no money object speaker that they'd use the best size driver for the job. And, after spending over $100k I hope they weren't expecting some one to buy a sub. Trust me though, I heard the Evidence, they don't need a sub. . But there has to be some reason why manufacturers use smaller bass drivers, if it was true that the larger woofers were more accurate some one would definitely offer them as a pure quality alternative.

I hate to get off topic but this is interesting. If you have any links or anything I'd be interested in seeing them.

There are VERY good reasons why 8", 10" and 12" subs are used - a lot of them have to do with the business side of audio:
1) looks
2) limited space in corners/between speakers...
4) Shipping/distribution costs - a HUGE reason for commercial retailers.
5) Room gain - more important for sealed subs, but hold for vented subs too..in smaller rooms, a smaller sub can acutally perform better in music-first applications - it won't win the SPL/low frequency extention pissing match, but I bet it can sound better. A room with the longest dimension 14 feet will exhibit transfer function starting at about 40 Hz...the 2nd order (theoretical) gain below 40 Hz is a perfect match to an 8" or 10" sealed woofer with F3 around 35-40 Hz....A big 15" woofer with that is flat until 23 Hz would probably exhibit a broad bass peak and not be a great match in a smaller room. My rooms have typically been around 20 feet long so I've designed my sealed subs to match that size...room gain begins around 28Hz at that room size.

Anyway...I think all of these speak to the marketability and profitability of providing smaller sized subs - let's be honest - there is undeniably waaay more demand for more convenient, smaller sized subs in the HT and Hi Fi industries. Also, by investing a bit more money into the woofer quality (taken from the increased shipping cost of a larger subs) they can just build a higher quality woofer in a smaller package for the same, or incrementally more money.
This is what we've been seeing lately. I would bet in many cases, the increased cost of designing a better woofer offests the distribution costs...net result, a smaller box that performs equal arrives in the store. But the more expensive you go the more the larger sizes will prevail. Up to a point...it probably swings back in the extremely high end range because the additional cost of designing a super 8" woofer isn't a big % of the speaker cost.

But all things equal, when those small woofers start reaching their xmax limits and power handling maximums, you'll want the bigger woofer. Put simply, the harder the woofer has to work, the worse it will sound. Efficiency and swept volume will come into play the larger the size.


Do you think the Dayton example is typical?
As long as the laws of physics are consistent across brands. Yeah, most of the subs I've built have used woofers made by specialty subwoofer companies, but I own 2 different Dayton designs...I've used Ascendant audio, Peerless, Seas, Usher, Hi-Vi, etc. Actually I think most of the Dayton's are built by Usher...could be wrong on that. The Reference line is.

Last point...I can't stress enough - the woofer size thing is an all-things-equal point. Three's a lot of factors. Things aren't always equal so it's hard to make cross comparisons from one size woofer to the next and arrive at accurate conclusions. I just hope people don't ignore larger woofers because of an old generalization - they may be missing out. Especially today, subs are built more affordable and better than ever IMO.

I wish I had the link to the Adire papers - they actually brought this discussion to CES 2004.


Maybe it's not actually the speed that makes the smaller drivers sound more accurate

You hit the nail on the head! Sometimes the phase distortion/group delay will make a sub appear a bit muddier or sloppier. If the sub has more linear distortion that's affecting sound quality too. After a while, our ears just can't pick up the extra benefits of a better transient response. And these factors can affect why some ported subs of higher quality can sound better than sealed subs, despite having inferior transient responses.

[Mr Peabody]

I haven't found exactly what I was looking for yet but I found enough to believe Kex has busted an audio myth here.

BTW - I ran across an impressive review of the SVS 2531. Geez, I want to try one of these things. Unless something happens to change my mind I will bring probably this very sub in for a test the next time I am in the market for a sub.

http://www.hometheatersound.com/equipment/svs_2531pcplus.htm

[kexodusc]

Wow...found Adire's old paper in a PDF...good read....I can email it to anyone, but the site won't let me upload it...it's around 45 kb and the site is limited to 19 kb.

PM me if you're interested...couln't even zip it down that small....

[Mr Peabody]

Isn't it just like the CE companies to give us smaller woofers and hide the truth behind a lie, half truth or myth, take your pick. I actually was a large woofer fan using Infinity Kappa 7's which were 12" 3-ways in a sealed enclosure. When looking for an upgrade it became discouraging because I couldn't find a higher quality speaker with large woofers. It took Dynaudio to convince me that quality bass can come from a smaller woofer. Although many speakers today are probably more accurate than my Kappa's there is still a certain unmatched character you get from a large woofer. I think years ago here we had a thread discussing smaller vs. larger woofer sound. I remember a salesman once tried to tell me two 6's moved as much air as a 12, 6+6=12 but when placing 6" circles on a 12" circle there is still plenty of uncovered space.

Shipping and space are good reasons to make small speakers but it would be nice if some one offered a quality single cabinet option with a 12 or 15 I guess Martin Logan could be an option but you would need some room size for sure with those.

[kexodusc]

I haven't found exactly what I was looking for yet but I found enough to believe Kex has busted an audio myth here.

BTW - I ran across an impressive review of the SVS 2531. Geez, I want to try one of these things. Unless something happens to change my mind I will bring probably this very sub in for a test the next time I am in the market for a sub.

http://www.hometheatersound.com/equipment/svs_2531pcplus.htm
Kex didn't bust anything...just did enough googling way back to learn for myself.

I noticed even TC Sounds, the guys who make SVS' woofers, sell and prefer the larger units - the motors in their 15" units are a whopping 40lbs...that's some magnet...

[Mr Peabody]

Aw, Kex, don't be modest on us, you didn't become our "Glorious Beacon Of Light" for nothing. :)

[Sir Terrence the Terrible]

You aren't alone here..even up until 2-3 years back I was of this opinion as well. In fact, my early posts here on subwoofer topics will often make such claims. I think Dr. Greene, Wooch, Sir T, etc all called me out on it at one point way back. I even downsized from a 12" sub to a 10" sub. I think in many commercial examples, the 10" subs just have stronger woofer motors than their 12" brothers, but when that's the case it's not a fair comparison - woofer size shouldn't be blamed...undersized motor design for the size of woofer should.

I'll go one step further...most 10" subs I owned were better musically than 12" subs I owned. How could I not arrive at that conclusion?

I do recall getting linked to the Adire research paper here that mathematically explained why size and mass are irrelevant. A boring read, but that was my first eye opener. I then started posting the question on other forums in the DIY community - it was pretty much unanimous. Woofer size doesn't affect transient response as much as excursion and motor design do. Motor design is critical. If the magnet is powerful enough and the voice coil inductance low enough, the woofer will move fast - if it's underpowered, it loses it's control the further the woofer moves out. Sealed cabinets also have big advantages here over ported cabinets

The Car audio and DIY guitar/bass amp communities have accepted and known this for quite some time...it's still taking time in the home audio community....Like I mentioned earlier - I think a lot opinions on subs were made back in the 80's and 90's when (by today's standards) subs were more expensive and not great performers. If people believe 15" woofers are worse sounding, they won't even ask a salesman to look at 15" woofers.
Sales staff aren't always in the know either.



There are VERY good reasons why 8", 10" and 12" subs are used - a lot of them have to do with the business side of audio:
1) looks
2) limited space in corners/between speakers...
4) Shipping/distribution costs - a HUGE reason for commercial retailers.
5) Room gain - more important for sealed subs, but hold for vented subs too..in smaller rooms, a smaller sub can acutally perform better in music-first applications - it won't win the SPL/low frequency extention pissing match, but I bet it can sound better. A room with the longest dimension 14 feet will exhibit transfer function starting at about 40 Hz...the 2nd order (theoretical) gain below 40 Hz is a perfect match to an 8" or 10" sealed woofer with F3 around 35-40 Hz....A big 15" woofer with that is flat until 23 Hz would probably exhibit a broad bass peak and not be a great match in a smaller room. My rooms have typically been around 20 feet long so I've designed my sealed subs to match that size...room gain begins around 28Hz at that room size.

Anyway...I think all of these speak to the marketability and profitability of providing smaller sized subs - let's be honest - there is undeniably waaay more demand for more convenient, smaller sized subs in the HT and Hi Fi industries. Also, by investing a bit more money into the woofer quality (taken from the increased shipping cost of a larger subs) they can just build a higher quality woofer in a smaller package for the same, or incrementally more money.
This is what we've been seeing lately. I would bet in many cases, the increased cost of designing a better woofer offests the distribution costs...net result, a smaller box that performs equal arrives in the store. But the more expensive you go the more the larger sizes will prevail. Up to a point...it probably swings back in the extremely high end range because the additional cost of designing a super 8" woofer isn't a big % of the speaker cost.

But all things equal, when those small woofers start reaching their xmax limits and power handling maximums, you'll want the bigger woofer. Put simply, the harder the woofer has to work, the worse it will sound. Efficiency and swept volume will come into play the larger the size.


As long as the laws of physics are consistent across brands. Yeah, most of the subs I've built have used woofers made by specialty subwoofer companies, but I own 2 different Dayton designs...I've used Ascendant audio, Peerless, Seas, Usher, Hi-Vi, etc. Actually I think most of the Dayton's are built by Usher...could be wrong on that. The Reference line is.

Last point...I can't stress enough - the woofer size thing is an all-things-equal point. Three's a lot of factors. Things aren't always equal so it's hard to make cross comparisons from one size woofer to the next and arrive at accurate conclusions. I just hope people don't ignore larger woofers because of an old generalization - they may be missing out. Especially today, subs are built more affordable and better than ever IMO.

I wish I had the link to the Adire papers - they actually brought this discussion to CES 2004.



You hit the nail on the head! Sometimes the phase distortion/group delay will make a sub appear a bit muddier or sloppier. If the sub has more linear distortion that's affecting sound quality too. After a while, our ears just can't pick up the extra benefits of a better transient response. And these factors can affect why some ported subs of higher quality can sound better than sealed subs, despite having inferior transient responses.

Sir T stands up wildly clapping and throwing wads of paper in the air.

Excellent post Kex!!!!

[Rich-n-Texas]

Aw, Kex, don't be modest on us...
Don't ya hate it when he does that?! :incazzato:

...you didn't become our "Glorious Beacon Of Light" for nothing. :)
Yeah, if only this site had 10 more like him. :rolleyes:

He'll even educate you on Major Appliance purchasing decisions, and how to set up a new house for maximum occupancy during the upcoming AR.com house warming party. :yesnod:
:thumbsup:

[kexodusc]

Don't ya hate it when he does that?! :incazzato:

Yeah, if only this site had 10 more like him. :rolleyes:

He'll even educate you on Major Appliance purchasing decisions, and how to set up a new house for maximum occupancy during the upcoming AR.com house warming party. :yesnod:
:thumbsup:
That Rich, any excuse for a party! Just gotta find all the party gear. I've never seen so many boxes - man, I accumulate a ton of junk!

I did find my Dremel tool! Been looking for that for 2 years!

I've discovered moving in and unpacking is waaay more fun than packing and moving out - it's like Christmas - "what's in this box?"

I'm without phone, internet, or TV for at least another week - the HT could be a another week or so before it gets setup - I've been unable to find an 80 GB PS3, and my Blue Jeans Cables are a week or so away from arriving - needed some longer runs.

Maybe if rains this weekend I'll build my screen...:idea:

[GMichael]

That Rich, any excuse for a party!

I know. He's a real party animal that guy. What should we do with him?


Just gotta find all the party gear. I've never seen so many boxes - man, I accumulate a ton of junk!
I did find my Dremel tool! Been looking for that for 2 years!
I've discovered moving in and unpacking is waaay more fun than packing and moving out - it's like Christmas - "what's in this box?"
I'm without phone, internet, or TV for at least another week - the HT could be a another week or so before it gets setup -

Know the feeling. We still have stuff that never got unpacked from 2 years ago. "Oh! So THAT's where that's been."


I've been unable to find an 80 GB PS3, and my Blue Jeans Cables are a week or so away from arriving - needed some longer runs.

A coworker (a former 360 fanboy) was able to get an 80 GB at Wally World yesterday. It was the last of the older ones with BC. The guy at WW told him that it was the last one they will get in too.


Maybe if rains this weekend I'll build my screen...:idea:

You are going with the laminate right? That should work out well. What are you using for borders?

[kexodusc]

You are going with the laminate right? That should work out well. What are you using for borders?

I'll hit a fabric store and see what they have in black velveteens and felts. I'll find something. Just staple it to the frame nice and neat and I should be ready to go.

[Rich-n-Texas]

This thread is inspiring me to get back to putting my acoustic panels together. Maybe I'll try the frame design Kex-o-matic has described in the past this time instead of using tack spray all over everything. The 3M super adhesive I used didn't hold up too well to the humidity.

[kexodusc]

This thread is inspiring me to get back to putting my acoustic panels together. Maybe I'll try the frame design Kex-o-matic has described in the past this time instead of using tack spray all over everything. The 3M super adhesive I used didn't hold up too well to the humidity.
Do you have a staple gun? Sure helps.

[GMichael]

I'll hit a fabric store and see what they have in black velveteens and felts. I'll find something. Just staple it to the frame nice and neat and I should be ready to go.

I look forward to the pics.

[L.J.]

You aren't alone here..even up until 2-3 years back I was of this opinion as well. In fact, my early posts here on subwoofer topics will often make such claims. I think Dr. Greene, Wooch, Sir T, etc all called me out on it at one point way back. I even downsized from a 12" sub to a 10" sub. I think in many commercial examples, the 10" subs just have stronger woofer motors than their 12" brothers, but when that's the case it's not a fair comparison - woofer size shouldn't be blamed...undersized motor design for the size of woofer should.

I'll go one step further...most 10" subs I owned were better musically than 12" subs I owned. How could I not arrive at that conclusion?

I do recall getting linked to the Adire research paper here that mathematically explained why size and mass are irrelevant. A boring read, but that was my first eye opener. I then started posting the question on other forums in the DIY community - it was pretty much unanimous. Woofer size doesn't affect transient response as much as excursion and motor design do. Motor design is critical. If the magnet is powerful enough and the voice coil inductance low enough, the woofer will move fast - if it's underpowered, it loses it's control the further the woofer moves out. Sealed cabinets also have big advantages here over ported cabinets

The Car audio and DIY guitar/bass amp communities have accepted and known this for quite some time...it's still taking time in the home audio community....Like I mentioned earlier - I think a lot opinions on subs were made back in the 80's and 90's when (by today's standards) subs were more expensive and not great performers. If people believe 15" woofers are worse sounding, they won't even ask a salesman to look at 15" woofers.
Sales staff aren't always in the know either.



There are VERY good reasons why 8", 10" and 12" subs are used - a lot of them have to do with the business side of audio:
1) looks
2) limited space in corners/between speakers...
4) Shipping/distribution costs - a HUGE reason for commercial retailers.
5) Room gain - more important for sealed subs, but hold for vented subs too..in smaller rooms, a smaller sub can acutally perform better in music-first applications - it won't win the SPL/low frequency extention pissing match, but I bet it can sound better. A room with the longest dimension 14 feet will exhibit transfer function starting at about 40 Hz...the 2nd order (theoretical) gain below 40 Hz is a perfect match to an 8" or 10" sealed woofer with F3 around 35-40 Hz....A big 15" woofer with that is flat until 23 Hz would probably exhibit a broad bass peak and not be a great match in a smaller room. My rooms have typically been around 20 feet long so I've designed my sealed subs to match that size...room gain begins around 28Hz at that room size.

Anyway...I think all of these speak to the marketability and profitability of providing smaller sized subs - let's be honest - there is undeniably waaay more demand for more convenient, smaller sized subs in the HT and Hi Fi industries. Also, by investing a bit more money into the woofer quality (taken from the increased shipping cost of a larger subs) they can just build a higher quality woofer in a smaller package for the same, or incrementally more money.
This is what we've been seeing lately. I would bet in many cases, the increased cost of designing a better woofer offests the distribution costs...net result, a smaller box that performs equal arrives in the store. But the more expensive you go the more the larger sizes will prevail. Up to a point...it probably swings back in the extremely high end range because the additional cost of designing a super 8" woofer isn't a big % of the speaker cost.

But all things equal, when those small woofers start reaching their xmax limits and power handling maximums, you'll want the bigger woofer. Put simply, the harder the woofer has to work, the worse it will sound. Efficiency and swept volume will come into play the larger the size.


As long as the laws of physics are consistent across brands. Yeah, most of the subs I've built have used woofers made by specialty subwoofer companies, but I own 2 different Dayton designs...I've used Ascendant audio, Peerless, Seas, Usher, Hi-Vi, etc. Actually I think most of the Dayton's are built by Usher...could be wrong on that. The Reference line is.

Last point...I can't stress enough - the woofer size thing is an all-things-equal point. Three's a lot of factors. Things aren't always equal so it's hard to make cross comparisons from one size woofer to the next and arrive at accurate conclusions. I just hope people don't ignore larger woofers because of an old generalization - they may be missing out. Especially today, subs are built more affordable and better than ever IMO.

I wish I had the link to the Adire papers - they actually brought this discussion to CES 2004.



You hit the nail on the head! Sometimes the phase distortion/group delay will make a sub appear a bit muddier or sloppier. If the sub has more linear distortion that's affecting sound quality too. After a while, our ears just can't pick up the extra benefits of a better transient response. And these factors can affect why some ported subs of higher quality can sound better than sealed subs, despite having inferior transient responses.

Great read Kex! I tried to give you some green brotha but it ain't gonna happen.


You must spread some Reputation around before giving it to kexodusc again.

[Rich-n-Texas]

Do you have a staple gun? Sure helps.
One that works right every time I squeeze the handle? No.

Remember, I built the first two panels combining ideas from people here. Stapling wouldn't have solved my problem anyway because the burlap is laid over top of the fiberglass, and the face of the panel is where the bubbling happens. This tells me that something didn't go well during the spray application, or the materials aren't right for tack adhesive.

Anyway, this is somebody else's thread, so I heed the floor now.

[Woochifer]

Excellent discussion, kex!

Fortunately, I downloaded Adire Audio's reference documents before the company closed shop last year. Too many good bits on their website to let go to waste. The links, in case anyone wants to read their findings on woofer speed and group delay, are posted below.

Adire Audio Woofer Speed Article (http://hometown.aol.com/sfwooch/audio/WooferSpeed.pdf)
Adire Audio Group Delay Article (http://hometown.aol.com/sfwooch/audio/GroupDelay.pdf)

The woofer speed article really debunks a lot of the myths about transient response. Adire's conclusion was that inductance is the causal factor in transient response, not mass. This is where kex's points about motor design and power come into play.

There are plenty of approaches to bass reproduction. Peabody's question as to why the Dynaudio Evidence (which uses 8" drivers) has so much bass reproduction can be answered very simply -- look at how many drivers that speaker uses, and look at the massive cabinet volume in the two bass units.

Four 8" drivers will have a surface area of approximately 200 square inches, while a single 15" driver's surface area is 177 square inches. The speaker itself is about 7 feet tall.

The reason why subwoofers typically use a single driver is simplicity. The Dynaudio Evidence uses a five-way crossover, which makes the design very complicated. Of course, with a speaker that costs more than $80,000, Dynaudio has the luxury of sparing no expense to get it right.

A well-designed 15" subwoofer primarily needs to account for the T/S parameters, and match those to the box dimensions (plus port dimensions, desired response curve, output, efficiency, etc.). It doesn't need to reproduce the entire frequency range, so the design can be optimized strictly around the low frequencies.

Part of the reason behind the Dynaudio Evidence's narrow profile (and the narrow of other speakers as well) is to minimize box diffraction. Box diffraction can affect the imaging coherency in the highs and midrange, which is one reason why speaker companies began moving towards using multiple 6.5" or 8.0" woofers to replace 12" and 15" woofers in speakers (along with the move towards 2-way speakers rather than 3-way speakers).

[Woochifer]

If that CV subwoofer uses an 18" driver and has a bass response down to 35 Hz, then it's very clearly aimed at pro audio markets where maximum output matters more than maximum bass extension. The Hsu and SVS subs are actually rated to go deeper than 35 Hz, but they also likely won't play as loud (won't matter much in a small to medium sized room). As Kex pointed out, you will get progressively more boundary reinforcement as the room gets smaller.

Generally, the choice in subwoofer depends on the room, and what the listener wants. A 10" subwoofer can go deeper and louder than a 15" sub. But, it would also require a more powerful amp, and you potentially have more distortion. There are no hard and fast rules about which one is better.

Hsu and SVS are very credible choices, so you won't really go wrong with them. But, the key to getting quality bass comes down to proper placement, calibration, and acoustical tweaking. On the latter point, you might want to do a topic search for the Behringer Feedback Destroyer and room acoustics. The BFD is used by a lot of home theater enthusiasts to equalize their subwoofers, and IMO it makes every bit as big a difference as the choice in subwoofer. You'd be amazed at how much better a sub sounds after getting EQ'd and properly calibrated.

We've had plenty of discussions on that topic, so you should look them up.