# Need "Special Purpose" Speaker Design Help



## Catman (Mar 18, 2008)

I need a set of small 'special use' speakers and am looking for assistance in design. First I need deep bass extension at low wattage. The speakers will never need to play over 85-90db ...they are going be semi near field speakers as they will be located 2'-8' away. They will never see more than 5W and most likely 2-3W max. I also need them to be reasonably small (portable) I have a couple of the 5 1/4" Tang Band subs lying around and have thought about using them.

Parts-Express.com:Tang Band W5-1138SM 5-1/4" Neodymium Subwoofer | subwoofer 5-1/4" subwoofer neodynium subwoofer tangband tb speakers tangband-22008

Any ideas suggestions are appreciated.

>^..^<


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## habagat (Dec 6, 2009)

Hi, this could be a challenge considering the low sensitivity of the driver. The only thing that comes to mind is a transmission line. They do play low and dont require much power, with an fs of 45 thats a 6.3 ft line undamped, with damping it could be considerably shorter start the line with 1.3 sd for a nice tight bass or go up to 1.45 for looser, boomier bass. Terminate the line at about 1 sd. Search the web for some mini t lines such as the aipairs, they are very compact tl's. Hope this helps.


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## 94VG30DE (Nov 28, 2007)

I've thought about using those as midbass speakers in my doors in a 2-way tweeterless setup, but haven't pulled the trigger yet. I would be giving them way more that 3W though, although I guess it's that first Watt that is the important one  Don't expect low-end extension from 3W, but you might be able to at least hear it. 

Personally with that low wattage and need to be portable I would be looking at a 2" or 3" wideband driver. 

I'm super curious what your "special purpose" is though


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## Catman (Mar 18, 2008)

94VG30DE said:


> I'm super curious what your "special purpose" is though


Nothing special ...my wife has a sleeping disorder and we have found some CD's that help induce 'Delta Waves' and help her to get into a deeper sleep. I have this covered for home as I use a Nak STASIS receiver and a pair of ADVENT AS-2 speakers on each side of the bed facing each other. 

Amazon.com: Advent AS2 Dual 6" 2-Way Tower (Single): Electronics

We travel a lot and need something portable. These are occasionally used for other music ...but since we are in a Hotel / Cruise Ship room we don't play them loud. It is a little louder than background music ...but not louder than normal conversation. 

Delta waves are in the 1-5hz range and no speaker can do that ...so they use low notes but different frequencies ....(example) right channel 30hz and left channel 33hz to create the 3hz needed.

We've been using a sub/sat computer speaker system when we fly. Use a pair of cheap Insignia coax bookshelf speakers and a NAK receiver when we driver. I'm looking at one of the T-Amps and something a little smaller for speakers.

I have thought about a larger than optimal enclosure since I'll never reach the max capabilities of the speakers at this low level.

But ...I'm not a speaker designer.

Hope this makes sense ...and wasn't too boring.

thanks,

>^..^<


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## TREETOP (Feb 11, 2009)

Hopefully you don't think I'm being a smartass, but these have ridiculously deep bass extension at low wattage and cancel out ambient noise also:
Studio Headphones ? Beats by Dr. Dre by Monster 
Not sure if headphones would work for her but it might be worth a shot?


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## 94VG30DE (Nov 28, 2007)

Cool special purpose. I know this is weird, but have you thought about rotary subwoofers? I don't know how portable they would be, but you might be able to find one that actually hits 3Hz by itself. But using the difference in frequencies to produce the oscillation is pretty cool. 
Maybe a mini transmission line with something on this page: 2 ~ 5-1/4 INCH SUBWOOFERS from Parts Express ship same day and come with 45 day money back guarantee. Free Shipping Available. Order free 10,000 product catalog. 

30Hz in a small package is kind of difficult though.


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## Se7en (Mar 28, 2007)

I have a few questions...

1. Do these need to be portable in the sense that they are battery powered or is it safe to assume that you will always have a power source?

2. Will you also be using these for music playback? Or can it be a single driver designed to play only the frequencies that you've identified?

3. Sort of an extension of question 2, does it need to be a stereo pair or would a single driver work?

I was thinking that you might contact Brian at Rythmik Audio to see if he could do a custom driver/amp for your needs. He specializes in subwoofers using a servo feedback system. Although he markets plate amplifiers to work with his drivers, my understanding is that his circuit could/will work with a number of A/B amplifier designs and considering the specific frequency range you're shotting for, he could design something to work for your needs which would also work in a very small enclosure. His 12" design operates cleanly down to 14hz in a 1' cube, sealed. Also, he is very reasonable and very knowledgable.

Good luck!


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## Catman (Mar 18, 2008)

TREETOP said:


> Hopefully you don't think I'm being a smartass, but these have ridiculously deep bass extension at low wattage and cancel out ambient noise also:
> Studio Headphones ? Beats by Dr. Dre by Monster
> Not sure if headphones would work for her but it might be worth a shot?


 Not at all ...she tried headphones for a while and can't get used to sleeping with them on. She can go to sleep with them but everytime she moves they wake her up.

Also, I've gotten used to the background music while we sleep as well.

I have looked at those headphones for myself.




94VG30DE said:


> Cool special purpose. I know this is weird, but have you thought about rotary subwoofers? I don't know how portable they would be, but you might be able to find one that actually hits 3Hz by itself. But using the difference in frequencies to produce the oscillation is pretty cool.
> Maybe a mini transmission line with something on this page: 2 ~ 5-1/4 INCH SUBWOOFERS from Parts Express ship same day and come with 45 day money back guarantee. Free Shipping Available. Order free 10,000 product catalog.
> 
> 30Hz in a small package is kind of difficult though.


I haven't thought about rotary subs ...that is a little 'high tech' for what I'm trying to do. I have a couple of those subs ...just didn't know what enclosure to use for what I need.



Se7en said:


> I have a few questions...
> 
> 1. Do these need to be portable in the sense that they are battery powered or is it safe to assume that you will always have a power source?
> 
> ...


1. I will always have a power source ...just looking for something that can fit in a 'carry on'. That is what we are using to carry the computer sub / sat system when we fly. I've been looking at something like this for power.

Integrated T Amp Tripath TA2024 Power Amplifier+Adapter - eBay (item 230447164924 end time Apr-08-10 02:37:38 PDT)

Also been looking to find a mp3 player that will play while on charge. This would be smaller than a portable CD player.

2 / 3. They will need to play close to 'full range'. For the CD's we use there is a wide range of tones ...I'd guess 30-15K. From what I can tell they use the lower frequencies for the delta wave induction. There is no 'beat' to the music ...it is all ambient. There needs to be 2 drivers for the stereo effect of the 1-5hz oscillation effect (from what I can determine)


This is where I found the CD's ...I have several of them and can highly recommend them if they are something you like or could use. There are several for relaxation and other uses.

Welcome to the Center for Neuroacoustic Research! Scientific Sound Healing, Dr. Jeffrey Thompson

If you will go down to the Delta Sleep System on this link you can hear what I'm talking about. There are 2 CD's in this set ...this sample is from the one we don't use, it is more 'musical' than the other one.

Also listen to the "Song of Earth" sample ...it is closer to the sounds of what we use.

Welcome to the Center for Neuroacoustic Research!

I also love some of these ....just play around on the site for samples of a lot of the CD's

Welcome to the Center for Neuroacoustic Research!

thanks again,

>^..^<


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## ItalynStylion (May 3, 2008)

Did I miss how deep these needed to go? What frequencies are we talking here?


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## ItalynStylion (May 3, 2008)

Never mind, saw your other post...

Low 30's will be tough to get while keeping them small but I'm sure you know that. What size dimensions are you trying to keep it under?


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## jasondplacetobe (Jun 15, 2009)

good info


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## tyort1 (Jun 2, 2010)

Get a massive amp and a good eq and you can put them in almost any box you'd like.


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## Catman (Mar 18, 2008)

tyort1 said:


> Get a massive amp and a good eq and you can put them in almost any box you'd like.


I really wouldn't think I'd need a 'massive' amp to get <90db.

>^..^<


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## Catman (Mar 18, 2008)

Bump ...this has been on hold for a couple of months ...still looking for some ideas. It is about time to get this one going.

These are a couple of options I'm considering for the top end ...crossed over ~400hz. Any ideas there?

Tang Band W2-803SM 2" Driver | Parts-Express.com

HiVi B3N 3" Aluminum Driver Round Frame | Parts-Express.com

Tang Band W3-1364SA 3" Bamboo Cone Driver | Parts-Express.com

Peerless 830983 2" Full Range Woofer | Parts-Express.com


thanks again for any help

>^..^<


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## Catman (Mar 18, 2008)

ItalynStylion said:


> Never mind, saw your other post...
> 
> Low 30's will be tough to get while keeping them small but I'm sure you know that. What size dimensions are you trying to keep it under?


I thought I'd bump this. I've had A LOT of crap going on in my life and have finally gotten back to this project. 

I'm trying to keep these around 0.3 cu.ft. ...0.5 max


thanks

>^..^<


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## Catman (Mar 18, 2008)

Bump


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## Catman (Mar 18, 2008)

Bump


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