Compact, but Powerful Sub - Help!

guangui · 12:57 AM

I have to take my current old trusty good sounding Audio Source SA-50 (8" FF) sub, and move from my family room setup to my home office room to use with my PC speakers (nearfield uFonken). Now my family room will be left without a sub, and instead of purchasing one, as I had done with the SA-50 or the HSU in my HT room, I want a DIY project.

I want a sub that can go really low, high teens Hz low. But, I don't want too large of an enclosure. I have run enclosure volume calculators (WinISD and others) for different affordable sub and woofer drivers, but the enclosures (ported) are big.

Is there an affordable enclosure/driver combination that is compact and can play in the +/- 18 Hz range? If possible 10", but if not possible then 12" driver. My family room is an odd configuration, part of an open plan, and a pain in the neck to accommodate large enclosures. A "coffee table" or "ottoman" can be an option.

Note: By affordable I mean no more than $150.00, but it will be better if much less expensive.

PMI · 18th February 2013, 01:19 AM

I came across this design on the ESP web page:

Sub-Woofer Controller

Basically, it is a way to overcome the link between resonant frequency and enclosure size. I have no idea if it works, or how to pronounce "Linkwitz", (chuckle), but apparently other people have built it with some success, and there are boards available to build it...

aspringv · 08:37 AM

Hi there,
I'm no expert, but I think you may have to give up on either cost, size, or freq response...

As I understand it you'd have to choose one of the following options
1) Sealed enclosure and linkwitz transform. best detailed ESP - The Linkwitz Transform Circuit there. Small, but highly inefficient, so you can make up on the inefficiency in amp watts until you hit max excursion on the driver.
2) some sort of folded horn box. efficient, but larger, and i hope you can work wood well... trying to find linky now to a good plan.
3) Sonotube. Cheap and effective, but large! https://www.google.com.au/url?sa=t&r...42553238,d.dmQ

Good luck!

edit; forgot to say - if you're thinking 'ottoman' be aware that you're setting yourself up for problems with bass nodes as your woofer will end up in a sub-ideal location. Apologies for the play on words...

guangui · 18th February 2013, 02:39 PM

Quote:

Originally Posted by PMI

I came across this design on the ESP web page:

Sub-Woofer Controller

Basically, it is a way to overcome the link between resonant frequency and enclosure size. I have no idea if it works, or how to pronounce "Linkwitz", (chuckle), but apparently other people have built it with some success, and there are boards available to build it...

Thanks!

Quote:

Originally Posted by aspringv

Hi there,
I'm no expert, but I think you may have to give up on either cost, size, or freq response...

As I understand it you'd have to choose one of the following options
1) Sealed enclosure and linkwitz transform. best detailed ESP - The Linkwitz Transform Circuit there. Small, but highly inefficient, so you can make up on the inefficiency in amp watts until you hit max excursion on the driver.
2) some sort of folded horn box. efficient, but larger, and i hope you can work wood well... trying to find linky now to a good plan.
3) Sonotube. Cheap and effective, but large! https://www.google.com.au/url?sa=t&r...42553238,d.dmQ

Good luck!

edit; forgot to say - if you're thinking 'ottoman' be aware that you're setting yourself up for problems with bass nodes as your woofer will end up in a sub-ideal location. Apologies for the play on words...

1. Will check

2. Not the best woodworker, but always willing to give it a try. I have all the necessary tools and power tools.

3. Too big will not work.

Not a big fan of ottomans, was just a suggestion.

chris661 · 18th February 2013, 02:47 PM

A folded horn will need to be big to be tuned that low.

You're looking at expensive subwoofer drivers (Peerless) and passive radiators, or a sealed box with at least a 15" driver, and several hundred (clean) watts to get the extension.

Anything smaller won't put out meaningful SPL in the teens of Hz in a sealed cabinet.

Are you sure you want to do this?

Chris

guangui · 18th February 2013, 05:29 PM

Quote:

Originally Posted by chris661

A folded horn will need to be big to be tuned that low.

You're looking at expensive subwoofer drivers (Peerless) and passive radiators, or a sealed box with at least a 15" driver, and several hundred (clean) watts to get the extension.

Anything smaller won't put out meaningful SPL in the teens of Hz in a sealed cabinet.

Are you sure you want to do this?

Chris

Yep, I want to do this, this is for HT not for music. If it takes more $, that is fine. I'm sure it will not be as expensive as a JBL Fathom. It can be ported, but ported are usually larger than sealed; at the same time ported go lower. Adding a passive radiator is an alternative I like.

OscarS · 18th February 2013, 07:37 PM

if you need that kind of extension and demand a small box, get ready to give up the idea of it being sensitive. No way around that. Gonna need tons of power to make up for the lack of sensitivity.

18Hurts · 18th February 2013, 07:40 PM

I built something like that

A 3 cubic foot box with a JBL GTO 1214 subwoofer, Exodus Audio 18" passive radiator tuned to 21Hz and a 200 watt amp. JBL in the front, PR in the back about 3 feet from the corner and 2 feet from the wall

Since it is a single PR on the back--it throws the box off balance which creates
an entertaining effect when the tones drop below 30Hz. That PR gets active and it shakes the floor to add that special something during movies.

Playing music does not shake the floor so not an issue.

For theater subs, my preference is passive radiators since I can accurately tune them to the room and no port chuffing or overload. To prevent the sub
from walking, it weighs about 30 KG with rubber feet to dig in the carpet.

If I was to do it again, I would of used two 15" passive radiators on either side of the box with the active 12" in the front.

tvrgeek · 18th February 2013, 09:38 PM

Sigh, another sub project expecting a tiny box, infrasonic roll-off and cheap. It just won't happen! For teens, you need a pair of 15's at least. Maybe 18's or the distortion will be too bad. BIG boxes. The laws of physics say so. Want proof? Go listen to a Sunfire.

Now, to be far more realistic, a couple of 12's in sealed boxes tuned to 25 or so with an Linlwitz Transform NOT TO EXCEED 4 or 5 dB, will do very well. Or look at the ESP controller which is a bit more flexable.

The LT is not just a bass booster, but a very carefully selected case to boost the slow initial rolloff of a low Q box. Low Q box means one BIGGER than the typical box. SF likes critical Q. Me too.

tvrgeek · 18th February 2013, 09:42 PM

Sigh, another sub project expecting a tiny box, infrasonic roll-off and cheap. It just won't happen! For teens, you need a pair of 15's at least. Maybe 18's or the distortion will be too bad. BIG boxes. The laws of physics say so. Want proof? Go listen to a Sunfire.

Now, to be far more realistic, a couple of 12's in sealed boxes tuned to 25 or so with an Linlwitz Transform NOT TO EXCEED 4 or 5 dB, will do very well. Or look at the ESP controller which is a bit more flexable.

The LT is not just a bass booster, but a very carefully selected case to boost the slow initial rolloff of a low Q box. Low Q box means one BIGGER than the typical box. SF likes critical Q. Me too.

18th February 2013, 12:55 AM	#1
guangui diyAudio Member Join Date: Feb 2013	Compact, but Powerful Sub - Help! I have to take my current old trusty good sounding Audio Source SA-50 (8" FF) sub, and move from my family room setup to my home office room to use with my PC speakers (nearfield uFonken). Now my family room will be left without a sub, and instead of purchasing one, as I had done with the SA-50 or the HSU in my HT room, I want a DIY project. I want a sub that can go really low, high teens Hz low. But, I don't want too large of an enclosure. I have run enclosure volume calculators (WinISD and others) for different affordable sub and woofer drivers, but the enclosures (ported) are big. Is there an affordable enclosure/driver combination that is compact and can play in the +/- 18 Hz range? If possible 10", but if not possible then 12" driver. My family room is an odd configuration, part of an open plan, and a pain in the neck to accommodate large enclosures. A "coffee table" or "ottoman" can be an option. Note: By affordable I mean no more than $150.00, but it will be better if much less expensive. Last edited by guangui; 18th February 2013 at 12:57 AM.

18th February 2013, 08:29 AM	#3
aspringv diyAudio Member Join Date: Sep 2010 Location: Peppermint Grove Beach, Western Australia	Compromises Hi there, I'm no expert, but I think you may have to give up on either cost, size, or freq response... As I understand it you'd have to choose one of the following options 1) Sealed enclosure and linkwitz transform. best detailed ESP - The Linkwitz Transform Circuit there. Small, but highly inefficient, so you can make up on the inefficiency in amp watts until you hit max excursion on the driver. 2) some sort of folded horn box. efficient, but larger, and i hope you can work wood well... trying to find linky now to a good plan. 3) Sonotube. Cheap and effective, but large! https://www.google.com.au/url?sa=t&r...42553238,d.dmQ Good luck! edit; forgot to say - if you're thinking 'ottoman' be aware that you're setting yourself up for problems with bass nodes as your woofer will end up in a sub-ideal location. Apologies for the play on words... Last edited by aspringv; 18th February 2013 at 08:37 AM.

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18th February 2013, 01:19 AM	#2
PMI diyAudio Member Join Date: Feb 2013 Location: Milwaukee, Wisconsin	I came across this design on the ESP web page: Sub-Woofer Controller Basically, it is a way to overcome the link between resonant frequency and enclosure size. I have no idea if it works, or how to pronounce "Linkwitz", (chuckle), but apparently other people have built it with some success, and there are boards available to build it...

18th February 2013, 02:47 PM	#5
chris661 diyAudio Member Join Date: Feb 2008 Location: Sheffield Blog Entries: 8	A folded horn will need to be big to be tuned that low. You're looking at expensive subwoofer drivers (Peerless) and passive radiators, or a sealed box with at least a 15" driver, and several hundred (clean) watts to get the extension. Anything smaller won't put out meaningful SPL in the teens of Hz in a sealed cabinet. Are you sure you want to do this? Chris

18th February 2013, 07:37 PM	#7
OscarS diyAudio Member Join Date: Jan 2011	if you need that kind of extension and demand a small box, get ready to give up the idea of it being sensitive. No way around that. Gonna need tons of power to make up for the lack of sensitivity.

18th February 2013, 07:40 PM	#8
18Hurts diyAudio Member Join Date: Nov 2010	I built something like that A 3 cubic foot box with a JBL GTO 1214 subwoofer, Exodus Audio 18" passive radiator tuned to 21Hz and a 200 watt amp. JBL in the front, PR in the back about 3 feet from the corner and 2 feet from the wall Since it is a single PR on the back--it throws the box off balance which creates an entertaining effect when the tones drop below 30Hz. That PR gets active and it shakes the floor to add that special something during movies. Playing music does not shake the floor so not an issue. For theater subs, my preference is passive radiators since I can accurately tune them to the room and no port chuffing or overload. To prevent the sub from walking, it weighs about 30 KG with rubber feet to dig in the carpet. If I was to do it again, I would of used two 15" passive radiators on either side of the box with the active 12" in the front.

18th February 2013, 09:38 PM	#9
tvrgeek diyAudio Member Join Date: Dec 2009 Location: Md	Sigh, another sub project expecting a tiny box, infrasonic roll-off and cheap. It just won't happen! For teens, you need a pair of 15's at least. Maybe 18's or the distortion will be too bad. BIG boxes. The laws of physics say so. Want proof? Go listen to a Sunfire. Now, to be far more realistic, a couple of 12's in sealed boxes tuned to 25 or so with an Linlwitz Transform NOT TO EXCEED 4 or 5 dB, will do very well. Or look at the ESP controller which is a bit more flexable. The LT is not just a bass booster, but a very carefully selected case to boost the slow initial rolloff of a low Q box. Low Q box means one BIGGER than the typical box. SF likes critical Q. Me too.

18th February 2013, 09:42 PM	#10
tvrgeek diyAudio Member Join Date: Dec 2009 Location: Md	Sigh, another sub project expecting a tiny box, infrasonic roll-off and cheap. It just won't happen! For teens, you need a pair of 15's at least. Maybe 18's or the distortion will be too bad. BIG boxes. The laws of physics say so. Want proof? Go listen to a Sunfire. Now, to be far more realistic, a couple of 12's in sealed boxes tuned to 25 or so with an Linlwitz Transform NOT TO EXCEED 4 or 5 dB, will do very well. Or look at the ESP controller which is a bit more flexable. The LT is not just a bass booster, but a very carefully selected case to boost the slow initial rolloff of a low Q box. Low Q box means one BIGGER than the typical box. SF likes critical Q. Me too.