Replacement Peerless Tweeter Diaphragm

joebass3

Anyone use the replacements that are available on Ebay? I had a dead Peerless lying around and decided for the price I'd give it a go. To my old ears they sound OK! My 7's and 10's are fine now, but I'll keep it and use it if needed. At least until I find a suitable original replacement.

Astrl55

Is that the replacement in your photo?
If not, do the replacements have the aperture tuning hole?

joebass3

Astrl55 wrote: »

Is that the replacement in your photo?
If not, do the replacements have the aperture tuning hole?

Yeah that is the replacement in the pic. I used my soldering iron to make the hole so it would match the others.

Gardenstater

Rob did a pair and generously sent them to me. Do you have the link to the replacement dome/VC that you used? I did not attempt the burning of the aperture hole. You did an excellent job! I found that they sounded very good. Just lost a little airiness, for want of a better word. I compared the way they sounded vs my original Peerless with some wind chime music and I could see that there was something missing in the upper harmonics. Freq. response showed a bit of a rolloff above 15kHz that wasn't present in the originals. I should try burning the holes and revisiting.

The original Peerless KO10DT is a bit emphasized above 10kHz and actually has a hump in the response there. I'll have to see if I can find the screenshot from the box of a NOS one that was being sold on eBay a while back.




I see this one on eBay. Is this the one?

https://www.ebay.com/itm/154896344185

joebass3

Gardenstater wrote: »

I see this one on eBay. Is this the one?

https://www.ebay.com/itm/154896344185

Yeah that's what I bought. I think I offered 10 bucks and he accepted. I wasn't expecting much, it was just a cheap experiment with a broken Peerless I had lying around. I only listened for a bit yesterday after I finished putting it together. I'll spend some time with it today and then just put my original back in and keep this for a backup.

xschop

Did your Peerless pole-piece have a felt disk or dome glued to it?

joebass3

xschop wrote: »

Did your Peerless pole-piece have a felt disk or dome glued to it?

Yes it did.

xschop

May need to run some white noise on those for awhile to help break them in. The surrounds are more stiff on the new aftermarket silks.

joebass3

Gardenstater wrote: »

I could see that there was something missing in the upper harmonics. Freq. response showed a bit of a rolloff above 15kHz that wasn't present in the originals. I should try burning the holes and revisiting.

All I have for testing is my cell phone and the Spectroid app. Obviously not the most reliable equipment, but you can see there is a drop off. The green vertical line is 15kHz. Fortunately (or unfortunately) for me, anything over 12kHz is beyond my range so i wouldn't hear it anyway. Ha!

Gardenstater

Depending upon what each vertical division represents, and considering probably no smoothing, I'd say that Wuhan looks pretty good. I didn't label these screenshots of my phone app, and it's been a while but I think the first 2 are of my L and R Peerless and the other two are of the Wuhan that I tested. Pretty sure I held the mic an inch from the tweeter with the whole speaker playing.

joebass3

Gardenstater wrote: »

Depending upon what each vertical division represents, and considering probably no smoothing, I'd say that Wuhan looks pretty good.

I labeled the graph to show the divisions. I zoomed the graph in to show the upper frequencies from 1k to 15k. What app are you using and what do you set smoothing to?

I sat in my normal listening spot to take measurements. I'll try getting closer to the tweeter and see if the results change.

Gardenstater

I meant the horizontal lines actually, are they spaced at 1dB intervals?

I used Advanced Spectrum Analyzer Pro and I set "averaging" to the highest setting. Graph with whitenoise still bounces around like crazy over time but I paused it and took a screenshot.

Since then I have learned that a better way is to set it to peak hold and to play a 5s sweep from 20Hz to 20kHz, or in this case you could do it for just the tweeter frequencies, like maybe 1kHz to 20kHz, even though crossover point is around 3kHz.

Gardenstater

For comparison this is what I got with a sweep tone, 1" from the L Peerless tweeter. Have to say that it was also after I did my "Dispersion Control Mod" which was basically a chunk of acoustic foam on the baffle between the tweeter and the midwoofer.

Yellow line (disregard background white line):



Whitenoise,1" from tweeter, before Dispersion Control Mod:

joebass3

So I downloaded some sweep tones, changed the smoothing from the default 35% to 80% in the Spectroid app, and put the microphone about 6" in front of the tweeter. I was impressed with the upper frequencies but there was a noticeable dip around 1kHz. Red line is the peak hold.

Gardenstater

Interesting! Almost as if the Wuhan was wired oppositely and there is some phase cancellation, but below the crossover point. Or, the Wuhan doesn't want to play as low as the Peerless and at 6" it is pretty off axis for the midwoofer.

PS: The way they both drop precipitously at around 13kHz is interesting too. Makes me wonder if it is an issue with the software or maybe your phone's mic. Or they don't want anyone else hearing what you said you can't lol.

joebass3

Gardenstater wrote: »

Interesting! Almost as if the Wuhan was wired oppositely and there is some phase cancellation.

Bingo! I had wired the new VC according to the instructions. There is a red dot on the Wuhan VC that denotes the positive side. After reading your response I decided just for grins I would swap the wires. Thanks @Gardenstater!

Gardenstater

Nice work! And I like the consistent appearance of the rest of the sweep graph that you are getting. Is it a 5 sec sweep? Logarithmic?

Now we need to find out what's up with the drop around 13kHz. Was the sweep tone file you downloaded from 20Hz to 20kHz?

joebass3

I downloaded 2 different files and they are both 20Hz to 20kHz files. Both of the files do the sweep very slowly and each file takes about 2 minutes to complete. I'm not too concerned with the drop at 13kHz since it seems to be consistent with the other speakers I tested that have original Peerless tweeters.

After running the sweeps and listening to it in conjunction with an original, I'd definitely use it if one of my originals bites the dust.

Gardenstater

It's good that you are satisified. I just can't help be curious though. Especially since it happens with both the Peerless and the Wuhan, something must be wrong for that to happen. It's too bad because that is the region where the Wuhan's deficiencies (if any) would be most likely to show up, especially if it is a compliance issue with the different surrounds/dome materials.

joebass3

I'm going to chalk it up to the app I'm using, my cell phone which obviously isn't a pro mic, or the source/sweep tones.

Yes the dip in the graph happens with the Peerless and Wuhan, but it happened with 6 Peerless (4 - Monitor 7's and 2 - Monitor 10's) tweeters and the Wuhan. All the graphs were similar which in theory I guess should mean similar performance. YMMV but after looking at the graphs and hearing the Wuhan for a few hours, I'm satisfied that I didn't waste $10. Lol!

xschop

You should try taking a hair dryer and heating the wuhan diaphragm up a few times to see if it helps speeding the break-in/relaxing....JAT