W4-1320sb

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Hey Chuck, did you finish them yet and if so do you have dimensions and/or pictures? I have the drivers and some scrap 1/2" plywood and want to try some test boxes. They will go close to the wall like I believe you said yours will, so I was going to try copying yours. This will be my first project, so I dont want to get too creative with it, at least until I break them in for a month or so.
 
Hi Happy, I've been working 6-7 days a week since labor Day so what can I do? My hands are tied so to speak. I did get a few days over Thanksgiving to paint them - Dupli-Color Mirage Blue/Red color changing paint - before the 10 degree weather set in. I'm very methodical and can't just sit down for an hour and really focus on what I'm doing. Maybe by Jan 15, sigh.....
I used 3/4" MDF in a 9.25H x 6.25W x 7.25DP 3.5 liter cabinet. 3/4" Parts Express Sonic Barrier damping foam on top bottom and back of cabinet. I think this may be thicker than necessary but I like the multi-layer concept. Thought about Deflex on the back panel but decided it's more a gimmick IMHO as it dispersed sound waves but no absorbtion. Also just some acousta-stuff from Parts-Express is said to be okay - 1/2 pound per cubic foot. I would like to try a combinations of Acousta-stuff and Sonic barrier - about 50% the recommended amount of each.
Here are my thoughts:
1) I highly recommend flush mounting the driver to get maximum HF extension. I can't believe Louis at Omega speaker does not do this on his single driver designs. He's an excellent woodworker and there is just no excuse. Sorry, end of rant.
2) I highly recommend routering the backside of the 3/4" thick front baffle in the areas between the mounting holes (#8 - I think - black painted stainless steel from ACE Hardware store - nice :) ) to allow the driver to breath. This was recommended for my W3-871s. Not sure if it's so necessary on the 1320SB as the magnet is the smaller neo design. Also less necessary with your 1/2" ply.
3) My cabinet unduly restricts L-F to 87Hz but I chose the size so they fit on my mantle. I thought about Parts-Express 7 liter #302-700 12 x 7.5 x 10 cab's fro $110 but T-B has VAS of 6 liter and not sure if 7 would be too big.
4) I've been playing around with my W3-871s some more. Tuned the 1.2 liter box to about 110 hz with a 1" x 2" long vent which was longer than the 1.3" I had been using. A 2.6" long lowered bass tuning to 95Hz but the highs got harsh and my ears started ringing. I think I over did the LF extension and the driver started breaking up, hence the increased HF distortion.
The point of this experiment was this: TB,and others use a rising response curve to offset HF beaming but in my reflective 13' x 15' room the speakers are unnaturallly bright and I must EQ the HF -2dB and boost the bass +2-4dB (via port or eq) to get them to sound correct. I use Denon UD-M31 mini-system which allows this but I want to go with Peter Daniel's Audiosector LM3875 gainclone with no tone controls.
Yes there is an increased sense of detail, vocals are a little easier to understand, sound is more open and airy, but not natural to me. Kind of reminds me of the poster who said Fostex 108 sigma was more open/detailed than TB. No doubt this a fantastic driver and better than TB but I think his listening impressions were due to the frequency balance as much as the driver quality itself. Less bass unloads the driver, increases efficiency, lowers distortion,......... but...... you get less bass. Which is bad in itself.
Long story long but that's why I think you should go with a bigger box - get all the bass you can. Check out Godzilla's website and Roman B's website accessed from Madisound.com. They both used a bigger box which is more sensible.
TB says the free air resonance is 75 hz so tune them to 75 hz, not 87hz like mine. With a rising response curve you won't be getting a big bass bump like the FR125 driver.
5) You could start with 2" ID port tube. P-E sells adjustable length to tune to taste. 1 1/2" is min for 25 watts but you need 2" for 50 watt amp. Go with a cab deeper than 7.25" to make room for longer port - otherwise it interferes with the driver.
6) I run the speaker wire direct from amp to driver and plug the hole in the back of the speaker with a little rubber cork. I use Rat-Shack magnet wire which is very thin dia and the rubber seals around the wire okay.

Are you running S.S. amp? T-B is good with s.s.

Good luck
 
ok, so, i kept seeing people compare this to the css fr125 and that REALLY bothered me. Until i discovered something...

I was looking for some info and opinions on some other 4" TB drivers when i stumbled upon some intriuging information...

Aparantly (i gotta check my sources, or maybe someone could confirm this for me...) Adire and CSS designed the FR125 and the WR125 but tang band produces them...

After a quick look around on TBs website, CSS, and partsexpress, it looks like they are, in fact, VERY similar drivers.

It would appear that the CSS drivers and the TB drivers have the same frame and i think spider and surround. The cone is different and the phase plug is different. Also these drivers don't use the XBL^2 technology, but i stand corrected on the similarities...

So, what i'm saying is...

These look like REALLY cool drivers!

I'd be VERY interested to see these in the sidefiring horn desing on Planet10's hifi website...

I'd be VERY VERY interested if someone were to start a group buy from PE or TB so we could get em even cheaper...
 
Corloc said:
They do look simular. As for sound, well I have not heard of anyone give a direct compairson. I like mine alot, and have them in Tom'Z PAWO cabs. They do very well.


how low does the bass get? 50s?

I'm gonna try a bunch of different tb drivers...

The first on the list is the 4" aluminum one...i've seen it used in a few different projects as a full range, i might add a tweeter tho...in fact, i probobly will...
 
I've been playing around with these drivers for some time.

I feel that they really, really need some notch filtering. At around 6 KHz, my set has a 5 or 6 dB peak.

Also, their rising frequency response is baffling... I used them on a bipole, and it seemed they needed some extra Baffle Step Compensation.

I'm going to build a small ported cabinet for them. I wonder whether I should try notch filtering and BSC correction... what do you think? How can I fix the rising frequency response?
 
I'm thinking about an array of bamboo TB drivers for a near-future project. I'm feeling an increasing urge to have an array in the home again; it's been too long! Roll them off circa 2KHz and cross-over to some nice ribbons. Could be interesting. Unless the CSS WR125s tempt me away first. Oh, choices! And then decisions: sealed or ported? Preferences guys?

Best
Scott
 
I put them in a 7 liter box tuned to 76 hz with a 3" port. I have about 200 hours on them and I still have the slight harshness in the upper midrange. Could this be the 6khz peak? I don't have any BSC on them yet, so maybe I will try that first, that should help, don't you think? I have them on my desk about 18" from the wall. Except for the slight upper midrange problem, they sound great. Decent bass and nice highs. I didn't have a router to flush mount them so I covered the front baffle with felt. Not sure how much that helped as they were still breaking in. Also, they can get pretty loud before compression sets in, I have them hooked to a Panasonic SA-XR55 and I can crank some heavy rock.
 
I was working with Martin's formulas for BSC. First I calculated the zobel, and it seems a bit strange that the driver has a Le of .01 mh, that with the Re of 6.8 gave me a zobel of 8.5 R and .18 microfarad cap. Does this sound right? I am going to start with 4 db baffle step, which came out to a 1mh coil and 4 R, as these are sitting on my desk, about 18" from the wall. Still not sure about that .18 microfarad cap though.....
 
I gave up on the bipolar towers (I'll leave them aside until I better understand this driver) and will start work on a 20 x 30 x 20 cms. box. It's all finished, so all I need to do is mount the drivers, tune it at around 65 Hz, and start working with LSPCad.

I was reading Vance Dickason's book. I may be able to tame the rising response with a conjugate network plus a resistor on the driver side, but I'm really not sure.

We'll see. I'll try to post some graphs and measurements this weekend.
 
OK... my speakers are now playing. I should be happy, but I didn't find the solution I was looking for.

I added a BSC circuit (simple inductor and resistor) and a parallel notch filter to tame the 7 KHz mode.

The first image shows the raw response of the driver in the box (tuned to about 65 Hz - I was surprised my drivers' Fs was around 110 Hz!).
 

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But, here's the thing I dislike: the impedance. It reaches 20 Ohms at 20 KHz! Even worse, 26 Ohms at 7 KHz.

My SS amp has no problems driving the speaker, but I really wanted to use it with an EL84 amp, and it has no highs to speak of.

I wonder if I should modify the crossover, or build a new pair for tube amps (I have 4 cabinets and drivers)... I need to play with LSPCad a bit more.
 

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