EPI Airspring - Audiocap Theta bypass Yeah or Nay?

[Maxamillion]

I'm currently rebuilding a pair of EPI 180's and I'll be using Dayton 1% caps for the tweeters, and I'm considering whether to bypass the Daytons with .01uF Audiocap Thetas. I did that with my T/E 100s, but that is a totally different tweeter. The Thetas added some sizzle, but do the airsprings need sizzle?

I'm looking for some experiences - who here has bypassed the tweeter caps on airsprings, with what bypass cap, and how did it sound?

By the way, my 180s have their birthdate stamped inside, 2/18/76. They just turned 33! The recap/refoam is their belated birthday present...

 

[Jonesy09]

I didn't do the bypass on my 150's but after I changed the main cap with Daytons the airspring seemed to be just right. The ususal disclaimers apply of course, my ears, my amp (Yamaha CR-620), my room. I would tend to think more sizzle would take them from sweet to harsh.

 

[luvvinvinyl]

I have used the Dayton Film & Foil bypass caps with the Dayton 1% caps, and found no harshness on my OLD EPIs. M50s and M100s, both airspring tweeters.

 

[Maxamillion]

Hmmm - It looks like

I will need to do the experiment. I'll try them w and w/o and see, since I already have the Thetas.

Thanks for the feedback.

 

[Jonesy09]

Please don't report back that the bypass extends the all-ready juicy high end. You will only be adding another project to my continually growing list.

 

[Maxamillion]

OK, Jonesy, I did try the 180 with and without the bypass. And....

Well, first off, the speaker is not completely re-assembled yet since the surrounds are drying, but I did the recap with the Dayton 1% caps and listened to the speaker without the woofers, since the caps only affect the tweeters anyway. I listened intently, then clipped the Audiocap bypass in, then took it out, then put it back in, etc., all the while with my ear very close to the tweeter.

The difference is subtle. I think I can hear slightly more of the very upper treble frequencies (cymbal splash for example) with the bypass, and overall the sound seems slighty smoother with the bypass. Keep in mind this is with my ear against the tweeter and no woofer playing. Whether or not this will be at all apparent when the woofers are playing and I'm sitting 8 feet away is another story altogether. Also, the caps are completely unbroken in, so that is another variable to take into account.

In short, if you haven't done the bypass, don't lose any sleep over it. The difference is very very small on the airspring tweeter.

 

[Robie]

I'll relay my experience which has a few similarities.

I recapped my garage sale Genesis Model 10s with Dayton 1%s. I believe the Genesis use the same tweeter as the EPIs. Unfortunately, I bought these with rotten woofers and recapped and refoamed at the same time before I ever heard them.

I was unhappy with the result. The tweeters were way too hot and forward. They were so "critical" sounding I couldn't listen to them with anything but the best recordings. Virtually no mid range.

I tried some resistors to tone down the tweeter but didn't like the result. I ended up bypass capping them with Thetas and they have become a bit more listenable. Overall, I agree that they sound noticeably smoother with the bypass cap no matter what equipment I drive them with.

When RayW visited last month I explained the problem and we listened to them on my main system. He agreed that the tweeters are still too hot and suggested that a notch filter may solve the problem. I have not tried that yet.

Others report acceptable results with the 1% Daytons so I'm not sure what's going on with my Genesis. My current theory is that the foam surrounds I got are too stiff affecting the overall balance of the woofer tweeter combo. I can however tolerate them with tubes on most recordings.

YMMV.

 

[Maxamillion]

Interesting. I'll bet your issue is with the woofer/tweeter balance, as the airspring is not usually known to be too hot/bright. I have used the Daytons on two sets of speakers now, and they sound pretty good, definitely smoother than Solens, which I won't use anymore in speakers (only in electronics like power supplies, where they shine).

 

[Robie]

Thanks, Maxamillion.

I knew that the crossover diagram on Humanspeakers.com utilizes a different cap value than what I used (I used a 10uF as that was what was installed in mine). However, the diagram on the Humanspeakers.com websites specifies an 8uF cap). http://www.humanspeakers.com/genesis/gen10.htm#xver

What I didn't notice until today was that the crossover diagram on this website also depicts the use of a choke (which I presume is an inductor). No inductor was present in the crossover of my Model 10s.

Again, I'm not trying to hijack this thread, it's just something that may explain my problem above.

 

[Maxamillion]

Hmm, that's a second order x-over on the tweeter in the diagram, which will roll off the tweeter at 12 dB/octave, twice as steeply as a simple cap (first order). If the first order filter you are using allows the tweeter to go too low, then it could end up sounding harsh.

 

[Robie]

Thanks, Maxamiilion. That may explain why the cap values are different too. 10uF was what was originally used in my speakers but 8uF is specified by Human Speakers (with choke).

BTW, I also bypass capped some smaller EPI 70Cs as well as some lowly RS Presidians that got a lot of buzz a couple years ago. IMO both were improved by the bypassing.

Good luck whatever you decide to do in the end and please report what you decide.

 

[shacky]

I also used the Dayton 0.01 Film bypass caps on 201 and 202. Sold the 201's and buyer very happy with them. Still have the 202's and they sound very nice.

I'm not sure the EPI really needs it though. If you already went for 1% Daytons, I'd try them alone and see if you like them.

 

[Maxamillion]

Well, they're done except for 1 woofer - I had one less surround than I thought I did (actually, I had two more 8" foams, but they weren't exactly the same as the others, so I'll wait for a new shipment to do the last one). In the meantime, here are a couple pictures. The first is the recap, the second is the one finished speaker. It sounds really nice! Can't wait to finish the job!

And to top it all off, I scored a minty pair of Genesis Physics 210s tonight, for free! Time to buy more surrounds...

P.S.: as you can see I decided to use the Audiocap Theta bypass - it just sounded a tad smoother with it than without.

 

[Maxamillion]

The speakers are done, and I've had them breaking in for ~48 hours. Tonight I listened to them for ~3 hours, with various material.

They sound very good, with lots of tight, deep bass and smooth highs. At this point, I'm thinking they may be a little too smooth, though. They seem to be missing that little bit of splash at the upper most end, but maybe it's just because I'm used to the EMITs and EMIMs in my Infinitys. One thing's for sure, the tweeters are smooth. Crosby, Stills and Nash harmonies sound excellent, and they can also rock out very well (AC/DC, Disturbed, Metallica all sound good).

All in all, these are very nice speakers, and will be staying for a while in the main system while I finish my Infinity RSIIb rebuild.