Home » Sponsored » Pi Speakers » Thiel-Small Parameter Search
Thiel-Small Parameter Search [message #47630] Thu, 01 September 2005 07:15 Go to next message
Spinjack is currently offline  Spinjack
Messages: 100
Registered: May 2009
Viscount
I have two Radio Shack 40-1034 drivers that I'd like to use to build a subwoofer but I'm not having any luck finding the T-S parameters for it. Any suggestions on where to look?

Also, any hints as to how make these sound good? I've read that they can be a bit sloppy. I don't need them to be "audiophile" quality since they will be used in a furnished breezeway to supplement some homemade bookshelf speakers that the 7pi's will be replacing.

My plan is to go the Isobaric (sp?) route and I thought about matching them to one of those subwoofer amps available from Parts Express (either that or an older NAD amp I bought on eBay). I don't want to go horn because of size contraints, but I though about a tower configuration to minimize footprint if the required box volume was too high.

Any thoughts?

Re: Thiel-Small Parameter Search [message #47631 is a reply to message #47630] Thu, 01 September 2005 07:24 Go to previous messageGo to next message
Wayne Parham is currently offline  Wayne Parham
Messages: 18783
Registered: January 2001
Illuminati (33rd Degree)

You probably already know about this website but just in case, did you check ThieleSmall.com?


Re: Thiel-Small Parameter Search [message #47632 is a reply to message #47631] Thu, 01 September 2005 08:58 Go to previous messageGo to next message
Spinjack is currently offline  Spinjack
Messages: 100
Registered: May 2009
Viscount
Actually, I didn't know about it. I had been using Google with little success. Thanks for the link.

Nothing [message #47633 is a reply to message #47631] Thu, 01 September 2005 10:45 Go to previous messageGo to next message
Spinjack is currently offline  Spinjack
Messages: 100
Registered: May 2009
Viscount
There doesn't appear to be any info about RatShack drivers on the T-S site. Any other suggestions?

Re: Nothing [message #47635 is a reply to message #47633] Thu, 01 September 2005 11:09 Go to previous messageGo to next message
Matts is currently offline  Matts
Messages: 359
Registered: May 2009
Grand Master
you could try to find out who made them for R.S.- may be a clue in a part # or something, then look up equivalent model. Fostex made some of their smaller full-range speakers.

Re: Nothing [message #47636 is a reply to message #47635] Thu, 01 September 2005 11:31 Go to previous messageGo to next message
Spinjack is currently offline  Spinjack
Messages: 100
Registered: May 2009
Viscount
I thought of that, I'll have to take a close look at any labelling on the drivers.

Re: Nothing [message #47643 is a reply to message #47636] Thu, 01 September 2005 16:17 Go to previous messageGo to next message
Wayne Parham is currently offline  Wayne Parham
Messages: 18783
Registered: January 2001
Illuminati (33rd Degree)

You could also have a go at measuring the T/S parameters. You don't need specializd test equipment and can obtain reasonably good data with your PC (as a signal generator) and a good DVM. See the post called "T/S Measurements" for a write up on this process.
Re: Nothing [message #47647 is a reply to message #47643] Fri, 02 September 2005 07:13 Go to previous messageGo to next message
Spinjack is currently offline  Spinjack
Messages: 100
Registered: May 2009
Viscount
Yeah, that was the direction I was going to go. I'm not sure how I will do Vas, though. I'm not sure I want to build an extra enclosure. If I did build it, I'd want to do it such that I can mount anything from a 6.5" up to an 18" driver.

Can you recommend some signal generation software for the PC? I don't have an oscilloscope, so I'll be restricted to an RMS DMM, but from the research I've done it appears that I should be able to get pretty close.

Re: Nothing [message #47648 is a reply to message #47647] Fri, 02 September 2005 07:15 Go to previous messageGo to next message
Wayne Parham is currently offline  Wayne Parham
Messages: 18783
Registered: January 2001
Illuminati (33rd Degree)

I forgot where I got my signal generator, but I'll E-Mail it to you if you like. You can probably search the internet and find several.


Re: Thiel-Small Parameter Search [message #47653 is a reply to message #47630] Fri, 02 September 2005 22:29 Go to previous message
GM is currently offline  GM
Messages: 114
Registered: May 2009
Viscount
Greets!

These are car audio 'IB' sub drivers so OB, very large sealed, or aperiodic is best, with the latter yielding the highest SQ. It's specs are ideal for a 'classic' stuffed TQWT and going isobaric will keep the line's CSA reasonable, so 12" square (inside dims) should work fine and a ~93.63" pathlength will tune it to ~30 Hz if stuffed along its length with ~48 oz of R-19 fiberglass. The beauty of this design is that the specs can be off quite a bit and still perform well by adjusting the amount of stuffing.

Catalog specs:

Fs = 30 Hz
Vas = 6.83 ft^3
Qts = 1.04
Pe (RMS/max) = 75/150 W
sens = 88dB/W/m (+/- 2 dB)
nominal 8 ohms

GM


Previous Topic: Where to get Modular amps
Next Topic: Ping: ColinHester
Goto Forum:
  


Current Time: Wed Nov 06 07:16:50 CST 2024

Sponsoring Organizations

DIY Audio Projects
DIY Audio Projects
OddWatt Audio
OddWatt Audio
Pi Speakers
Pi Speakers
Prosound Shootout
Prosound Shootout
Miller Audio
Miller Audio
Tubes For Amps
TubesForAmps.com

Lone Star Audiofest