Help with Advents

[Pete B]

Consider that the NLA impedance dips very low, it is less of a problem in the decrease position so it
is good that you're running them there.
Is your amp rated for 4 ohm loads? Does it produce more power into 4 ohms?
I often run a 200W/ch amp rated for 2 ohm loads.

Advents are bright speakers, that said, properly refoamed they should produce nearly flat bass to the
low 40s, few speakers are capable of this.
You might like BSC, surprised that no one mentioned this:

Large Advent Line Level Baffle Step Compensation (BSC) Build Instructions

Edit: People ask if this is built in one or two box(s), here is a pictorial image that should give an idea as to what it is physically in one box, line level with RCA jacks: https://audiokarma.org/forums/attachments/bsc_pictor_cr-jpg.582488/ I've had several people ask me off-line how to build...

audiokarma.org

 

[Newbie01812]

Consider that the NLA impedance dips very low, it is less of a problem in the decrease position so it
is good that you're running them there.
Is your amp rated for 4 ohm loads? Does it produce more power into 4 ohms?
I often run a 200W/ch amp rated for 2 ohm loads.

Advents are bright speakers, that said, properly refoamed they should produce nearly flat bass to the
low 40s, few speakers are capable of this.
You might like BSC, surprised that no one mentioned this:

Large Advent Line Level Baffle Step Compensation (BSC) Build Instructions

Edit: People ask if this is built in one or two box(s), here is a pictorial image that should give an idea as to what it is physically in one box, line level with RCA jacks: https://audiokarma.org/forums/attachments/bsc_pictor_cr-jpg.582488/ I've had several people ask me off-line how to build...

audiokarma.org

Thanks for the advice Pete. I am a little bit of a fish out of water in some of these areas. Relatively competent with electronics in general but I have to admit a lot of this is a little new to me.

I am running a Pioneer SA-8500 so I believe the speakers should pair well. I am attaching the technical specs of the amp that probably mean more to you than me.

I am feeling a tiny bit better about the situation in general because although I am very happy with my refoam job, I think the new foam is/was just taking a little time to break in, as bass definitely sound a little better now, after a few hours of using than it did right out of the blocks.

I am going to read your advice on BSC. Again not something I have any experience with, so I need to get my head around your suggestion but the literature you have provided appears to be more than comprehensive, so I will start by reading through the PDF and see if I am understanding a little better then.

 

[kmagnuss]

I replaced the caps and resistors in mine today... super easy job.
The old caps measured 14.5 uf and 15.8 uf, so most likely changing to the 13 uf didn't do much to the crossover point... maybe raised it 1-200 hz. I couldn't tell much of a difference between them when I tested the first one I changed compared to the original.
But the actual 'repair' is that now the switch works on each speaker due to all 4 resistors being broken (open circuit on each). The 'normal' position sounds best in my room for most music... the only position that worked prior to the repair was the enhanced, which was just a tad too much for me.

Anyway... hope you bang yours out soon...

-Mag

 

[drumbum]

I replaced the caps and resistors in mine today... super easy job.
The old caps measured 14.5 uf and 15.8 uf, so most likely changing to the 13 uf didn't do much to the crossover point... maybe raised it 1-200 hz. I couldn't tell much of a difference between them when I tested the first one I changed compared to the original.
But the actual 'repair' is that now the switch works on each speaker due to all 4 resistors being broken (open circuit on each). The 'normal' position sounds best in my room for most music... the only position that worked prior to the repair was the enhanced, which was just a tad too much for me.

Anyway... hope you bang yours out soon...

-Mag

Did you measure the caps that went in?

 

[Lux Man]

So these are NLA’s? Could you be so kind as to post pictures front and back without the grills?

Also as we all know since we don’t have your ears nor do we know what your judgement is for bass/treble these types of questions can be challenging. I’ve been watching this thread since the beginning, and I would’ve thought it would’ve been resolved by now. Hopefully you won’t mind posting pics.

 

[kmagnuss]

Did you measure the caps that went in?

Man I'm such a dummy... I didn't even think to measure any of them until after everything was back together. I'll pull a woofer out and see if I can get a reading on a new cap. Watch, they'll be basically the same, lol.

 

[kmagnuss]

So these are NLA’s? Could you be so kind as to post pictures front and back without the grills?

Also as we all know since we don’t have your ears nor do we know what your judgement is for bass/treble these types of questions can be challenging. I’ve been watching this thread since the beginning, and I would’ve thought it would’ve been resolved by now. Hopefully you won’t mind posting pics.

Yes, NLA's. Here's a couple bad pics...

 

[kmagnuss]

 

[Newbie01812]

So these are NLA’s? Could you be so kind as to post pictures front and back without the grills?

Also as we all know since we don’t have your ears nor do we know what your judgement is for bass/treble these types of questions can be challenging. I’ve been watching this thread since the beginning, and I would’ve thought it would’ve been resolved by now. Hopefully you won’t mind posting pics.

Mine are literally identical to @kmagnuss ‘s speakers. I actually don’t have a picture of the rear but again, identical so nothing different to show. Here is the front and my crossover…

IMG-2347 hosted at ImgBB

Image IMG-2347 hosted on ImgBB

ibb.co

IMG-2346 hosted at ImgBB

Image IMG-2346 hosted on ImgBB

ibb.co

 

[kmagnuss]

Mine are literally identical to @kmagnuss ‘s speakers. I actually don’t have a picture of the rear but again, identical so nothing different to show. Here is the front and my crossover…

IMG-2347 hosted at ImgBB

Image IMG-2347 hosted on ImgBB

ibb.co

IMG-2346 hosted at ImgBB

Image IMG-2346 hosted on ImgBB

ibb.co

I think "identical" to mine is a bit of a stretch... yours are so much nicer! Man, now I'm even more bitter about the previous owner's glue-fest foam repair job.

 

[Newbie01812]

I think "identical" to mine is a bit of a stretch... yours are so much nicer! Man, now I'm even more bitter about the previous owner's glue-fest foam repair job.

lol I did a lot of work on them aesthetically to get the wood looking nice again and the woofers were in a sorry state…although it was essentially just dried out, no damage. My old man did used to take really good care of his gear.

 

[kmagnuss]

@drumbum I pulled a woofer and tried to get a measurement but it won't give me one... do I need to unsolder a side to get a value like on receivers?

 

[drumbum]

@drumbum I pulled a woofer and tried to get a measurement but it won't give me one... do I need to unsolder a side to get a value like on receivers?

sure.

Got a way to test esr?

 

[kmagnuss]

sure.

Got a way to test esr?

Unfortunately I don't.

 

[Doug G.]

Technically, in both cases, the wrong surrounds were used. They should have just a 1/8' flange around the outside to just fit onto the little ledge on the frame. The outer flange should not extend up onto the angled part of the frame.

If the right sized roll is present (17mm - 18mm) it won't really make any difference as long as the outer flange is well adhered to the frame. However, the roll in both cases, again, are technically incorrect. They are too small. They appear to be only about 12mm - 13mm. Electrical/acoustic measurements would have to be taken to determine what difference, if any, there are compared to drivers with correct surrounds. The smaller roll WILL restrict cone travel.

One other thing. The surrounds need to be very compliant (floppy). If you hold one (not installed) by one side, it should not self-support but should droop down. It should not be "rubbery" like a lot of them I've seen. It should have kind of a duller, more porous appearing surface and not shiny and smooth.

Doug

 

[drumbum]

Technically, in both cases, the wrong surrounds were used. They should have just a 1/8' flange around the outside to just fit onto the little ledge on the frame. The outer flange should not extend up onto the angled part of the frame.

If the right sized roll is present (17mm - 18mm) it won't really make any difference as long as the outer flange is well adhered to the frame. However, the roll in both cases, again, are technically incorrect. They are too small. They appear to be only about 12mm - 13mm. Electrical/acoustic measurements would have to be taken to determine what difference, if any, there are compared to drivers with correct surrounds. The smaller roll WILL restrict cone travel.

One other thing. The surrounds need to be very compliant (floppy). If you hold one (not installed) by one side, it should not self-support but should droop down. It should not be "rubbery" like a lot of them I've seen. It should have kind of a duller, more porous appearing surface and not shiny and smooth.

Doug

Hi Doug,

Have you refoamed many Acoustic Research speakers?

 

[Doug G.]

Yes and I have 5 pairs of original Advents, most with the Masonite woofers and a couple of pairs with all-metal woofers.

Doug

 

[Mrv8q]

I recently refoamed 2 pair of Advent NLAs. My surrounds were originally attached to the back of the woofer cone; yours look like the front. Don’t think it would affect the bass that much. I also used a bead of Mortite around the woofer frame for sealing. Next Up: rebuild x-overs.

Good on you for assisting your dad!

 

[Doug G.]

Yes, I forgot to mention the position of the inner flange. The Masonite woofer is the only one with the flange in front of the cone. The rest all should have it positioned behind the cone edge.

Doug

 

[Doug G.]

Hi Doug,

Have you refoamed many Acoustic Research speakers?

Oops, I misread this. I thought you wrote "Acoustic Suspension..." I haven't refoamed any Acoustic Research speakers.

Doug