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TrueBluePhil

Crossover Cap Value

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I also took the time to replace to old square foam in them and replace them with the OC fiberglass insulation that Carl suggestion doing and WOW! what a difference this makes. The bottom end is back and mids are much smoother. I am beginning to believe that I might have put in the original foams squares in incorrectly and this contributed to the problem.

Well after much frustration I decided to change the caps and resistors again. I replaced them with 13uF SonicCap GEN I Capacitors and Mills Resistors on two of my NLA and my speakers are back to playing smoothly with the detail I have had for 30 years.

Phil, I'm confused.

In my limited experience with OLA and NLA speakers, I discovered, as you did, that the foam blocks are not very good damping material and that fiberglass works better. I think both Carl and PeteB recommended that and they know what they are talking about. So if the FG made such an improvement, why did you tear into the xo again?

Doug may be right, and your own listening is consistent with that, but I'm skeptical. For every report of "astonishing" differences among different caps, there are convincing reports on the other side of the issue, saying most people don't hear any difference and even if they do a difference is not an improvement necessarily.

As I understand it, the best argument in favor of film caps over NPEs is that they will last longer. If we want to be true to the original design, we're better off using new NPEs.

I think it was Roy who spoke in favor of the very inexpensive Carli mylar caps because their ESR is closer to that of the original NPEs and that COULD affect the sound.

And your issue may not have been the xo at all (other than the incorrect cap value as stated in your OP). I recently drove myself crazy while working on some Cizek KA-1s. To make a long story short, one speaker was behaving strangely and giving wildly poor specs on the DATS software. I had totally rebuilt the xo, testing each component as I did so. The woofers had been professionally re-foamed and tested by Millersound. Swapping drivers convinced me the problem was in one box, meaning the xo. I pulled the xo and started tracing everything, pulling parts off the board, re-soldering, etc.

Well, maybe this story isn't so short after all :unsure: Anyway, turns out one woofer screw had snagged the new foam gasket, causing an air leak! I discovered that by using the "3 finger push test" then listening all over the speaker with a stethoscope.

Sorry for being long-winded. My point is; maybe it wasn't the caps.

Kent

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Hi JKent,

After replacing the foam with fiberglass the speakers did sound much better but I was still getting the harsh sound in the upper mid and highs so that is why I went back in to change the caps again.

To let you know I am very anal when it comes to sound and the smallest things really bug me. I have mixed sound for years for bands and shows because I have such critical ears for mixing. Not to brag but I have mixed sound for Maranatha Music and even did a show for Ricky Skaggs. Hell, I was at a show for the group America and the sound tech they usually use to mix got sick and couldn't do so the band hired a local person and it was so bad after one song I went to sound booth and talked to the guy into letting me help him since he didn't know the music. Well after a half an hour went by my wife was worried about me and came looking and there I was mixing the sound and the tech they hired was sitting down. People tell me all the time that I should have been a sound engineer for a studio and I agree. I missed my calling but I still enjoy music. Well enough of this bragging.

Well I replaced the other caps and resistors in my other two Large Advents and now all four of them are playing smoothly. I don't know what the Daytons sounded so badly but they did. The SonicCap Gen I are much smoother and the low end sound it much more punchy. When I replaced the caps and resistors while in the cabs i checked everything, solder joints, wires, etc and found nothing incorrect. So I don't know what else to say then the new caps and resistors work much better on my Advents the the Dayton products.

On the foam blocks verses the Fiberglass, this made a huge difference. Advent engineers should have been shot for using the foam. They knew better but went over the cliff trying to keep their cost down. What did they save by doing this? Maybe $1.00 per speaker. Not worth the loss in sound quality.

Anyways the speakers now sound like the rich sound I had before but with more definition and soundstage. I realize that there are much better sounding speakers out there but not for the money which is what Advent did with the Large Advents. Make a speaker for $100 that competed with speakers at a $1000. Advent did a great job with that strategy but in their later years gave it up for cost. Then Jensen took over and we all know the rest of the story. Shame on them.

Anyways, I can now listen to my music with pleasure again

Phil

Phil, I'm confused.

In my limited experience with OLA and NLA speakers, I discovered, as you did, that the foam blocks are not very good damping material and that fiberglass works better. I think both Carl and PeteB recommended that and they know what they are talking about. So if the FG made such an improvement, why did you tear into the xo again?

Doug may be right, and your own listening is consistent with that, but I'm skeptical. For every report of "astonishing" differences among different caps, there are convincing reports on the other side of the issue, saying most people don't hear any difference and even if they do a difference is not an improvement necessarily.

As I understand it, the best argument in favor of film caps over NPEs is that they will last longer. If we want to be true to the original design, we're better off using new NPEs.

I think it was Roy who spoke in favor of the very inexpensive Carli mylar caps because their ESR is closer to that of the original NPEs and that COULD affect the sound.

And your issue may not have been the xo at all (other than the incorrect cap value as stated in your OP). I recently drove myself crazy while working on some Cizek KA-1s. To make a long story short, one speaker was behaving strangely and giving wildly poor specs on the DATS software. I had totally rebuilt the xo, testing each component as I did so. The woofers had been professionally re-foamed and tested by Millersound. Swapping drivers convinced me the problem was in one box, meaning the xo. I pulled the xo and started tracing everything, pulling parts off the board, re-soldering, etc.

Well, maybe this story isn't so short after all :unsure: Anyway, turns out one woofer screw had snagged the new foam gasket, causing an air leak! I discovered that by using the "3 finger push test" then listening all over the speaker with a stethoscope.

Sorry for being long-winded. My point is; maybe it wasn't the caps.

Kent

Phil, I'm confused.

In my limited experience with OLA and NLA speakers, I discovered, as you did, that the foam blocks are not very good damping material and that fiberglass works better. I think both Carl and PeteB recommended that and they know what they are talking about. So if the FG made such an improvement, why did you tear into the xo again?

Doug may be right, and your own listening is consistent with that, but I'm skeptical. For every report of "astonishing" differences among different caps, there are convincing reports on the other side of the issue, saying most people don't hear any difference and even if they do a difference is not an improvement necessarily.

As I understand it, the best argument in favor of film caps over NPEs is that they will last longer. If we want to be true to the original design, we're better off using new NPEs.

I think it was Roy who spoke in favor of the very inexpensive Carli mylar caps because their ESR is closer to that of the original NPEs and that COULD affect the sound.

And your issue may not have been the xo at all (other than the incorrect cap value as stated in your OP). I recently drove myself crazy while working on some Cizek KA-1s. To make a long story short, one speaker was behaving strangely and giving wildly poor specs on the DATS software. I had totally rebuilt the xo, testing each component as I did so. The woofers had been professionally re-foamed and tested by Millersound. Swapping drivers convinced me the problem was in one box, meaning the xo. I pulled the xo and started tracing everything, pulling parts off the board, re-soldering, etc.

Well, maybe this story isn't so short after all :unsure: Anyway, turns out one woofer screw had snagged the new foam gasket, causing an air leak! I discovered that by using the "3 finger push test" then listening all over the speaker with a stethoscope.

Sorry for being long-winded. My point is; maybe it wasn't the caps.

Kent

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