Sda-2 have very little bass

sansuibutch

Tony M wrote: »

RandyCroissant wrote: »

Are these tweeter domes as good as the originals I don’t see any specs

Well, when some original SL2000's sound like a honkin dented trumpet, these are a lot nicer.

Now some SL2000's have survived and don't hurt the music as bad as most do, these rebuilt SL2000's are still twice as nice.

I think someone did take some measurements before and after break-in of these.

So my new coils came in. 16 of them. I trimmed a tweeter faceplate last night just to check it out. I searched the sl2000 hack thread to see what kind of jig you built to make the holes in the diaphram to line up with the magnet and faceplate but didnt see it. I dont think you posted it. I liked you idea about dremeling out the grooved holes on the diaphragms so the coil would line up every time. Can you elaborate a littlenon that one for me? If so i think i can get to work on these. And of course im excited like a little kid ahhaa

sansuibutch

Actually that wont help. The dome itself isnt perfectly centered in the blastic bezel.

sansuibutch

See how one hole lines up and the rest dont. The diaphragm has a little play as the coil moves around in the magnet and i cant get any other ones to line up as i move it. I guess theres not much quality control over there in china hahah

sansuibutch

This way seems easy enough if i can run a small test tone and center these as i pinch the faceplate screws down. Prolly not as easy as it sounds but might be able to pull it off ahahh

sansuibutch

Do you knwo what length screws you went with to acomadate the extra thickness with the new diaphram?

sansuibutch

sansuibutch

I measured it looks like screws with the threaded section being 1/4" long will be perfect. On the hunt.

sansuibutch

I found the right size screws. Everything fits together great. Im just going to need to find a way ro center voice coils and maybe a cleaner way to remove some of the faceplate material for the new connection terminals. Last night i just used an angle grinder to remove enough plastic to get it in there right. This one is kind of a trial run. I have a lot of sl2000 tweeters laying around.

Gardenstater

Can you play a 3kHz (or thereabouts) test tone with the plastic bezels removed and the screws holding the dome assembly in place with washers under the heads? Then once you find a position where spl is loudest on a dB meter you could tack it in place with some adhesive so the whole thing doesn't shift when you remove the screws. I bet 9 times out of 10 just dropping it in place and centering by feel gets you close enough but the test tones could verify that.

sansuibutch

Gardenstater wrote: »

Can you play a 3kHz (or thereabouts) test tone with the plastic bezels removed and the screws holding the dome assembly in place with washers under the heads? Then once you find a position where spl is loudest on a dB meter you could tack it in place with some adhesive so the whole thing doesn't shift when you remove the screws. I bet 9 times out of 10 just dropping it in place and centering by feel gets you close enough but the test tones could verify that.

Ya i can definelty play a 3khz tone. I dont think i need to do it with the face off. I can reach the connection terminals to move the diaphram by itself. Il prolly try to snug thr screws just a tiny bit so i can just barely move the plasic and diaphram around till i think its right and then tighten the screws

sansuibutch

Gardenstater wrote: »

Can you play a 3kHz (or thereabouts) test tone with the plastic bezels removed and the screws holding the dome assembly in place with washers under the heads? Then once you find a position where spl is loudest on a dB meter you could tack it in place with some adhesive so the whole thing doesn't shift when you remove the screws. I bet 9 times out of 10 just dropping it in place and centering by feel gets you close enough but the test tones could verify that.

So as im just messing around and testing the one i have together. It seems to be a few decibels quiter than the stock sl2000 at some frequencies. At some frequencies its only a decibal or two but at some frequencies it is a good four or five decibels quiter. It that just to be expected or am i not getting the coil as centerd as i think i am?

Gardenstater

I don't know, that's a good question but the SL2000 is not noted for being a very smooth frequency response tweeter.

https://forum.polkaudio.com/discussion/182943/the-tale-of-5-tweeters-sda-tweeter-replacement-guide/p2

Tony M

I engage a loudness or contour button and these SDA2 or SDA2b speakers sound perfect. The SDA2's with 3 woofers / 2 tweeters sound amazing. The SDA2's still have SL2500 in them and no harsh sound comes from them. I think they were babied all these years.

Bass issue fixed with using the bass increasing buttons.

Now the hum....I've been very busy doing other things. I thought about diving in again tonight but I stuck with fixing some ESS speaker coveers I made 30 years ago.

Maybe my next little job will be to REALLY get the hum out of the Adcom system.

I left the CD player on last night and today. Playing a CD tonight, the sound sounded like crap! I didn't know what was at fault. I switched CDs and then there was no sound. I turned the CD player off for 5 seconds and it played and sounded fine for hours. Then it skipped and I turned it off for the night. There isn't any space for the CD player to breathe. The Adcom pre is heating it up.

Another project...

sansuibutch

Gardenstater wrote: »

I don't know, that's a good question but the SL2000 is not noted for being a very smooth frequency response tweeter.

https://forum.polkaudio.com/discussion/182943/the-tale-of-5-tweeters-sda-tweeter-replacement-guide/p2

Ya thays not very smooth at all. I knew it had the little "spike" around 13khz but didnt know it fluctuated so much throughout most of its range. Il have to check the new one and old one at a bunch of different frequencies and take some notes. I have a little set on monitor 5 im gonna toss it in and give it a listen and compare to the other

Tony M

I meant to say SL2000s.

I can't hear above 11khz.

sansuibutch

So far i have listened to the tweeter in a set of 5jr. It does sound a lot better then the originals but it is quiter. If i turn the treble up some it cmsounds great. But the lower output doesn't have me convinced its the best replacement diaphram. A little while ago i hooked it up to a white noise generator and il let that play for a few days. Hopefully it will loosen up enough to make the difference.

Gardenstater

The ones I had experience with, that were in a Peerless magnet motor, were a little on the bright side compared to my original Peerless of 1979 vintage, but rolled off a bit more above 15kHz. Harmonics were ever so slightly noticeably lacking with instruments like wind chimes etc.. They did get smoother with extensive breakin but remained brighter than originals. Check out the frequency spectrum while playing some whitenoise and get a baseline before you break them in. I used Advanced Spectrum Analyzer Pro on my Android phone. Impedance and Inductance are 2 important parameters that need to be the same if you are hoping for anything like the same tonality IMO.