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Proac problem: tweeters or crossover?

Recently, something moved me to listen closely to the tweeters, and when I couldn't hear anything I hooked up the speaker cable just to the tweeter binding posts. I can't say there was no sound at all, because there was the faintest of recessed, tinkly sound that didn't seem to vary much with the level of the volume control.

I called up Modern Audio and they told me just to get the Scanspeak D2010s from Madisound. I soldered them in this morning. Now the new tweeters are a bit louder than before, but not nearly as loud and not as strong on the higher frequencies as I would have expected. They still sound subdued, recessed and tinkly/jangly, but not as much as before, and there's a bit more change in level when varying the volume control. This is as always with the cable hooked up only to the tweeter binding posts.

So...is this how they're meant to sound, or is there a problem with some component in the crossovers? If there is, it must be the same in both speakers' crossovers. I wish the result of the change-over had been less ambiguous: either virtually no sound, or a great improvement. Instead, it falls somewhere in between, but the result makes me think that I haven't solved the problem.

BTW, the Response 2.5s must be ~17 years old. Custom yew finish bought new from Accutronics in Ann Arbor in 1998/99. The mid-woofers still sound great.

Does anyone know what a Proac tweeter driven in the way I've described should sound like when it's functioning correctly?
128x128twoleftears
ctsooner
2,480 posts
 
I was just about to say polarity and then read your response, lol. I have had many sets of Proacs since the 90's (just sold off three pair) and everytime we worked on the tweeters, we were so careful to hook them back up correctly as the first time we didn't and it sounded similar to what you are sharing. In anything that old, it could be a failed component in the crossover. Are you able to hook them up to another system to see if it's the speaker or the electronics?
timrhu
2,779 posts
 
Hard to know exactly what you're hearing but tweeters alone don't make a lot of the sound when music is played. Assuming the crossover point is above 2kHz, there wouldn't be much information to produce as the majority of the music signal is below a the tweeters cutoff.
I once bought a pair of Eminent Technology speakers with a blown tweeter. I didn't notice until I was standing directly in front of the of the faulty speaker and noticed no energy from the tweeter ribbon.
twoleftears's avatar
twoleftears OP
5,313 posts
 
Thanks for responses.

I did install the new tweeters carefully, and they definitely are in correct polarity. I noted that the internal hook-up cable was labelled Bandridge Superflex 2.

The mid-woofers sound great, so it isn't the electronics.

I'm using Synergistic Research Signature 2/3, and I've hooked both the thick and thin runs of cable up to both the tweeter and the mid-woofer binding posts, individually, to confirm that everything's running as it should.

Basically, my questions boil down to this. If a tweeter is blown, or has failed from age, will it pass any sound at all, or can it pass a little "throttled" sound? Likewise, if a component in a crossover is going bad or had gone bad, depending on what that component does, can the mid-lows be left totally unaffected, while the highs are impacted in the way that I've described in my original post?

I have to confess to being baffled and frustrated from the results I've got so far. When I installed the new tweeters, I either expected no improvement (=crossover the problem) or 100% improvement (=solved!). Instead, I got about a 25% improvement. I'm still struggling to understand how this could be, unless Proac tweeters, when run on their own, sound very different from how you'd expect a tweeter to sound when not underpinned by the other drivers.
twoleftears's avatar
twoleftears OP
5,313 posts
 
P.S. I'll try and describe what I'm hearing from the tweeters.

The basic sound level (volume) is a total mismatch with that of the mid-woofers, if they were running. The tweeters are at a much lower level. It's hard to imagine that when both drivers are running, the tweeters would contribute more than 2% to the total sound.

The quality of the sound coming out of the tweeters is very distant, like it's several rooms away; it's thin, tinny, tinkly, jangly, disembodied. Also, curiously, it doesn't seem to have a lot of upper-octave energy.
zd542
5,339 posts
 
There's a couple of things to consider here. The first is that the new tweeters are going to break in, and will sound different when that happens.

"I'm using Synergistic Research Signature 2/3, and I've hooked both the thick and thin runs of cable up to both the tweeter and the mid-woofer binding posts, individually, to confirm that everything's running as it should."

Those are 2 runs of completely different cables, they're not just thicker. Different materials are used. You need to try the speakers with either 2 runs of the exact same speaker cables, or 1 run and use the binding post jumpers.
Those cables that you have are a band aid type fix for a speaker with a very harsh tweeter like B&W. You don't need that with the 2.5's.

It wouldn't be a bad idea to list your entire system.
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