So, my brother brought over 4 blown Cerwin-Vega Pro Stax PSX-153 speakers...

[Brian Steele]

Re: So, my brother brought over 4 blown Cerwin-Vega Pro Stax PSX-153 speakers...

We plan to do some extended power tests later today. Got a Crown Macrotech 1200 on-hand for to provide the power. Hopefully the neighbours are not home tonight .

Another quick update: the speakers with the updated x-overs passed the power tests just fine, so at this point I have no reservations in using the x-over tweaks previously mentioned, if I'm faced with this situation again. I ran the test with two of the modified PSX-153s running off of one channel (to ensure that they got exactly the same signal), and the POC TH off the other. While the POC TH was able to keep up with one PSX-153, two was a little too much for it.

Right now he's trying to source the drivers I suggested to convert the spare cabs to subs. Should be a fairly simple project to convert the cabs (some additional cross-bracing, blocking the existing vent holes, and adding a massive vent where the midrange/tweeter unit is normally mounted).

[Brian Steele]

Re: So, my brother brought over 4 blown Cerwin-Vega Pro Stax PSX-153 speakers...

Right now he's trying to source the drivers I suggested to convert the spare cabs to subs. Should be a fairly simple project to convert the cabs (some additional cross-bracing, blocking the existing vent holes, and adding a massive vent where the midrange/tweeter unit is normally mounted).

Just updating this thread - we found it difficult to pass up on the opportunity to purchase the Dayton PA380 drivers when they were offered at a reduced cost. Turning the cabinet into a "subwoofer" cabinet turned out to be a bit more work than I expected. It was leaking from several places (and of course those leaks were more audible when playing only bass frequencies). And the side panels, as I mentioned before, were really in need of some bracing, which was addressed by adding a cross brace on the inside of the cabinet just below the handles. I used a 337.5 cm^2 vent that's 32 cm long which according to HornResp is supposed to tune the cabinet to around 42~44 Hz, but actual Fb turned out to the 37 Hz, maybe due to the vent's proximity to the side walls. I'm debating whether or not I should trim the vent to achieve the target Fb, or leave it like is and let my brother try it out in his pub. It did seem to survive a brief power test intact - I did hear some obscene rattling sounds, but those turned out to the my kitchen cupboard doors vibrating .

A quick'n'dirty FR test is show below. Seems pretty decent. The distortion curve is Ok - the peak above 400 Hz is well above the intended passband of this speaker, so I'm not going to worry about it.


I used a Behringer iNUKE3000DSP for the testing. Nice amp, particularly considering the price. The DSP options really come in handy too. 48dB/oct LR filters? Yep, it can do that. Dynamic EQ? Yep, it can do that too. I'm thinking of buying one (instead of the Crown I was previously considering), and replacing the fan with a quieter version, for testing purposes and to use as the amp for my to-be-built new subwoofers.

[kblackmore]

Re: So, my brother brought over 4 blown Cerwin-Vega Pro Stax PSX-153 speakers...

From what it appears, you have the software necessary to assist you in designing a more proper 3-way crossover. I would avoid the bulb protection on the tweeters like the plague unless you drive them directly from the amplifier (the bulb's resistance changes as it gets hotter, effecting the crossover frequency). Klipsch came up with a good tweeter protection circuit for his AA crossovers (used in the Klipschorns and La Scalas) using zener diodes. I would tend to go that direction. Definitely go with properly sized componants to avoid problems in the future. Good Luck!!

[kblackmore]

Re: So, my brother brought over 4 blown Cerwin-Vega Pro Stax PSX-153 speakers...

Sorry, newb mistake, didn't realize blog went 4 pages

[jont]

Re: So, my brother brought over 4 blown Cerwin-Vega Pro Stax PSX-153 speakers...

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I used a Behringer iNUKE3000DSP for the testing. Nice amp, particularly considering the price. The DSP options really come in handy too. 48dB/oct LR filters? Yep, it can do that. Dynamic EQ? Yep, it can do that too. I'm thinking of buying one (instead of the Crown I was previously considering), and replacing the fan with a quieter version, for testing purposes and to use as the amp for my to-be-built new subwoofers.

The DSP on the iNukes is great for the price. The fan mod would make it acceptable in the home too.
I am looking forward to see what the 12000 can or cannot do.

[Brian Steele]

Re: So, my brother brought over 4 blown Cerwin-Vega Pro Stax PSX-153 speakers...

(resurrecting an old thread)

My brother (or someone at that nightclub) managed to blow two of the rebuilt CVs - the ones that used the new crossovers provided by CV, not the rebuilt ones I created. Nothing too horrible - the two "protection lamps" wired in series with the mid drivers were blown in both crossovers. Of course no-one is owning up to what happens. He says the speakers were hardly used. The stale drink splashes across the cabinets suggest otherwise to me. As a short-term fix I simply bypassed the lamp protection in each xover with a piece of wire (there's no such protection for the mids in the original x-over anyway) and I yanked three of the four 39uF caps that were present in the filter section for the bass speaker for each x-over, which basically dealt with the low impedance problem with the stock x-overs that I reported earlier in this thread.

Anyway, while examining the speakers, I hooked up one of the CVs (one with a rebuilt x-over) and one of the repurposed cabs to an iNuke 3000DSP, made a few adjustments to the DSP settings (dynamic EQ, x-over, limiting, and a bit of gain for the repurposed cab) and cranked it up for them to get a listen. They were pretty impressed.

Now they want me to put together a whole DIY solution for the club.

What have I gotten myself into?

The "club" is about 40 ft x 45 ft with an "A" roof that's about 20 ft high in the middle and perhaps 15 feet at the sides. The roof is covered with a layer of sound insulation, but that's it as far as sound treatment is concerned.

Anything I come up with has to have some measure of redundancy because of the time it would take to replace anything, so multiple cheap amps instead of one expensive one, and ditto for speakers. Right now I'm thinking of about 8 12" 2-way tops and the same amount of 18" subs in simple vented alignments driven by two iNuke 3000DSPs (for the tops) and two iNuke 6000DSPs for the bass should do the trick. The tops will be biamped but will also be equipped with basic 2-way x-overs. The DSP in the amps will be used to provide all the EQ, x-over and delay functions. And they will be password-protected and locked away from those flippin' DJs who think that if the gain control isn't all the way to the right, the system isn't loud enough...