OLA crossover help please

[Doug G.]

Originally, the two tweeters had different size magnets to match the efficiency of the tweeters to the woofers.

The Smaller Advent woofer was less efficient and so the magnet was made smaller so the tweeter wouldn't overpower the system.

The VC DC resistance is the same for either.

Later on, however, Advent evidently put some large magnet tweeters in the Smaller Advents. Why? I don't know. Maybe they discovered there wasn't that much difference and they ran out of small magnets. Who knows?

You should definitely get a larger magnet tweeter for your original Advents. 3" square as opposed to 2.5" for the smaller.

Doug

[JKent]

Thanks Doug. That's VERY helpful!

I pulled the bad tweet and can hear something rattling around inside. Not a good sound. Don't know if it can be repaired but I'll look for a replacement.

Kent

[Carlspeak]

Finished the crossovers, put one speaker together. I used 33oz of fiberglass, consistent with Carl's write-up but although they sound "good" they seem a bit bass heavy compared to the AR91s.

Any suggestions?

Are your AR91's now your reference speaker? Don't understand why any comparison needs to be made.

Does the speaker's voicing please you?

[JKent]

Are your AR91's now your reference speaker? Don't understand why any comparison needs to be made. Does the speaker's voicing please you?

Having a reference speaker helped me hear immediately that something was wrong. Sometimes the reference is the AR91, sometimes the 3a, sometimes the 2ax. At first I thought "bass heavy" but soon discovered that was not the case--it was a defective tweet. Not sure yet whether I like the voicing of a properly working OLA, because I have to replace one tweeter. Have one for sale?

Kent

[Carlspeak]

Well, the tweeter being DOA certainly explains alot.

PM me. Yes, I do have some spare OLA tweets.

[Pete B]

I actually prefer to use a reference speaker that I trust.

Condider that you will adapt to frequency response errors so

give any new speaker time for adjustment. Play a variety of

music and give it a few days, play some of your favorite test

tracks.

Check the masonite to metal glue joints on any replacement

tweeters and run a bead of new glue around if it looks or

feels bad.

[JKent]

They are finished and working properly! Thanks all--especially Pete and Carl. Pete for your Advent page and all the guidance, encouragement and prodding  And Carl for advice on bracing, the proper amount of FG stuffing to use and last but not least for providing a good tested tweeter to replace the one dud.

Oh, and David. Hope I didn't "hijack" your thread. Seemed like the logical place to pursue the topic. How are your OLAs coming along?

Just starting to do some listening. The speakers available for comparison were AR2ax's and 3a's. The 91s are disconnected.

The Advents sound good on brief listening to jazz, symphonic and pop. But in each case I prefer the AR3a. A fairer comparison is probably the 2ax and although the OLA and 2ax sound different the jury is still out on which is "better." YMMV. I will give your BSC circuit a try Pete, but have to wait until October to do that.

Here's a photo of current projects in my "work room". OLA atop AR3/3a conversion. Is that a "stacked Advent?" 😄

AR2ax's are on shelves. The AR91s, Pinnacle PN6+ and MicroStatics are not hooked up right now. Using a completely re-capped MAC4100 receiver (100wpc driving the 4 ohm AR3a, 75wpc driving the OLA)

Total cost, including original purchase, surround kit, all new caps, inductors, resistors, some stick-on rubber feet and a "new" tweeter: About $190. Much bang for the buck!

Kent

[dynaco_dan]

They are finished and working properly! Thanks all--especially Pete and Carl. Pete for your Advent page and all the guidance, encouragement and prodding And Carl for advice on bracing, the proper amount of FG stuffing to use and last but not least for providing a good tested tweeter to replace the one dud.

Oh, and David. Hope I didn't "hijack" your thread. Seemed like the logical place to pursue the topic. How are your OLAs coming along?

Just starting to do some listening. The speakers available for comparison were AR2ax's and 3a's. The 91s are disconnected.

The Advents sound good on brief listening to jazz, symphonic and pop. But in each case I prefer the AR3a. A fairer comparison is probably the 2ax and although the OLA and 2ax sound different the jury is still out on which is "better." YMMV. I will give your BSC circuit a try Pete, but have to wait until October to do that.

Here's a photo of current projects in my "work room". OLA atop AR3/3a conversion. Is that a "stacked Advent?"

AR2ax's are on shelves. The AR91s, Pinnacle PN6+ and MicroStatics are not hooked up right now. Using a completely re-capped MAC4100 receiver (100wpc driving the 4 ohm AR3a, 75wpc driving the OLA)

Total cost, including original purchase, surround kit, all new caps, inductors, resistors, some stick-on rubber feet and a "new" tweeter: About $190. Much bang for the buck!

Kent

Hi Kent

If you still have the KLH Twelves and Microstatics connected together, have you tried to see what the pros and cons are?

[Pete B]

Good to hear Kent! I've been on generator power for a few days

with no internet. Everyone I know is safe, no major issues with

the storm. It was no where near as bad as they were saying in

our area.

[Carlspeak]

They are finished and working properly! Thanks all--especially Pete and Carl. Pete for your Advent page and all the guidance, encouragement and prodding And Carl for advice on bracing, the proper amount of FG stuffing to use and last but not least for providing a good tested tweeter to replace the one dud.

Oh, and David. Hope I didn't "hijack" your thread. Seemed like the logical place to pursue the topic. How are your OLAs coming along? ,,,,,,,,,,,,,

Kent, I'm anxious to hear what you think of the overall voicing with having changed out all the coils, including the woofer coil.

BTW, all's well here in north-central CT. Minor, overnight power outage Sunday and that was it. We were very fortunate.

[JKent]

All's well here too in NW NJ. A couple of power outages. Others were not so lucky. My sis in Pompton Lakes (about 20 miles from here) has 8 feet of water in her basement and a house 2 blocks from her blew up! Here in the Appalachian mountain range we're high and pretty dry, but roads leading DOWN from the mountains are pretty washed out.

Carl, I need to listen more and I'm not sure of the vocabulary to describe voicing. With the tweeters functioning properly now I'd say they are bright compared to the AR 3a or 91. Maybe I can give you better descriptions after more listening. Their sound is closer to the 2ax than the 3a.

Kent

[Carlspeak]

Carl, I need to listen more and I'm not sure of the vocabulary to describe voicing. With the tweeters functioning properly now I'd say they are bright compared to the AR 3a or 91. Maybe I can give you better descriptions after more listening. Their sound is closer to the 2ax than the 3a.

Kent

My take on the effect of the woofer air coil is it helped balance the sound, somewhat like Pete's BSC does. At least it did in my case. However, the coil I used was at a higher value than the one you used. IIRC, it was 1.8 mH.

[JKent]

Trying to figure out how to respond to your question, Carl. I'm thinking the OLAs are a bit harsh or strident. Maybe "forward". Meanwhile the AR3a's and AR91s sound quite similar to each other: Great!

I've listened briefly to a variety of music: Also Sprach Zarathustra, Eric Kunzel's Orchestral Spectaculars, Roy Orbison, Miles Davis, acoustic guitar, acoustic jazz (Jazz at the Pawnshop) and ALWAYS like the ARs better (slight edge to the 91s). Miles always puts a smile on my face but with the OLAs I thought my ears would bleed. Guess "fatiguing" may be another adjective.

Well, maybe that's too harsh. They really do sound pretty good UNTIL I compare them to the AR3a or 91. Too bad. A good deal of effort went into them, and I WANT to love the OLAs, but I don't. Wonder if the BSC addresses the issues as I perceive them. Maybe what I'm hearing is the " fairly serious midrange coloration" Pete described in his first thread on the BSC: http://www.classicsp...h=1

Apologies in advance to those Advent lovers offended by my comments.

YMMV

Kent

[JKent]

Follow-up:

I never thought caps had to "break in" but maybe I'm wrong. The OLAs are sounding better. More likely, the new surrounds are breaking in.

Depends on the music of course. On big orchestral pieces the AR3a's are clearly (IMHO) superior, but today my wife and I auditioned a Diana Krall disc and the OLAs sounded very good indeed. (side note: The Bozak MB-80s also do well with female vocals). And even on the "big" orchestral pieces, the OLAs are sounding better.

So, I retract some of my negative reviews. Haven't tried again on the discs I hated (Miles, Erich Kunzel) but things are looking up.

Next month I'll borrow Pete's BSC for further evaluation.

Kent

[Dchristie]

Folks - I am new to the forum and have been following the OLA crossover discussions and I have a couple of questions for any of the " experts" regarding the crossover components. From looking at the schematics, it looks as though Advent changed the tweeter inductor values and cap value from 0.8 mh and 16 uF /16uF in the eary model to .45 mh and 16uF /8uF for the later models. I assume this was to raise the crossover from 1000 hz to a higher crossover point for the tweeter to improve reliability ( just speculating on my part ) .

I would like to rebuild my crossover in my Large Advents by eliminating the DPDT switch altogether and then balance the highs with the lows ( if needed) with a fixed resistor L-pad later on. So what would be the proper capacitor and inductor values for the 2nd order crossover ( would like to retain the 1000 hz crossover point) without the DPDT switch and all of it's associated components in the circuit ?

Thanks

Dean