Last Updated: 5-10-98
This page has measurments I've taken on commercial speakers. All of the measurements were made using Liberty Audiosuite.
The name says it all.
These are the drivers that I've done some measurments on so far:
SEAS 27TFFC, 1" Soft Dome Tweeter.
MCM 55-1170, cheap but not too bad 6.5" driver.
JBL 122d. DVC car sub, paper cone, foam surround, vented pole piece.
Seas CA25RE4X/DC, high quality paper cone, rubber surround, long throw 10" driver.
Motorola Powerline Piezo horn tweeter...ugly response..but cheap and loud.
Outlines current work, and past projects. Cool mini-sub for a car, check it out.
Pictures of speakers, raw drivers..etc.
Any questions, comments send me email at [email protected].
This page has Word95 documents (zipped) that are collections of the best posts from the DIY Speakers and Related Projects Mailing List.
This is page is going to be pretty rough at first, and it will always be under construction.
Currently I'm working on two different speaker projects:
1. Motional feedback subwoofer system.
3-8-98
I've recieved the 200W amp module from OCS. I now fear for the structural integrity of my house. I've measured 105-110 dB at 30 Hz. Not bad at all. A very primitive version of the servo system has been incorporated, frequency response is improved, but the cirucuit is not meant for the woofers I'm using. (Hint, it's actually the circuit used in the previous version of the project, with a 12" JBL dvc car sub.) Uncorrected response 3dB is around 50Hz. Not really a sub in the strict sense of the word, corrected is around 40Hz.
2-26-98
I have a 200W OMP/MF MOSFET amplifier module on order from Old Colony Sound Labs. It should be here on Monday.
I've also ordered a terminal cup, and purchased some stuffing material. This weekend I hope to get the woofers in the box, and powered with the sub. That means that the low pass xover will be designed next weekend for temporary use in a non-servo mode.
2-23-98
The subwoofer is going to use two Seas CA25RE4X DVC subwoofers, they are sitting on my living room floor right now. Not doing too much good there, but I definitely have some plans for them.
Currently I'm working on finishing the box. The first coat ended up being a bit too red, so I'm working on how I'm going to fix that. The box is 2 cubic foot sealed enclosure built out of 3/4 inch MDF. Veneered in flat cut maple and extensively braced.
I've measured the T/S parameters of the Seas woofers, and they aren't that close to the specs provided by Seas. I've heard that Seas isn't particularly famous for measuring correctly.
2. Full range tower system.
5-10-98
I've ordered a pair of Seas 27TFFC 1" soft dome tweeters from Madisound, and a pair of Audax HM170Z0 6.5" woofers from Zalytron. I've got the tweeters, I'll probably have the woofers on Monday. (I hope, I'm anxious to see what they are like.)
The tweeters are similar to the Seas 27TFF tweeters (which Madisound also sells) but have a chamber in the back to lower the resonant frequency. The frequency response is not quite as flat, but supposidly you can use the chambered version down to 2000Hz, third order xover. I've measured the Fs (spec. 900 Hz.) to be 1000Hz. I'll probably try to cross them over at 2500 Hz or so. The farther away from Fs your crossover point is the more program power the speaker system will handle.
2-23-98
This hasn't gone too far yet. Still in the initial planing stages, right now it will consist of a 10" woofer (Peerless?) 6.5" Mid (Focal/Audax???) and a 1" textile dome tweeter (Seas/Vifa???)
Two weeks ago I purchased Liberty Audio Suite from Liberty Instruments . This program is fantastic. I highly recommend it to anyone who has plans on building anything more than small two way systems. The features and price make it the best deal.
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