What's wrong with my C-notes?

[DrewsBrews]

Driver break in? Really? Didn't expect to see that here. Respectfully no, that has nothing to do with my issues.

PE support suggest break in and I just rolled my eyes....

Doesn't seem particularly respectful to me. Crap like this only hurts the hobby, and is why I have largely kept to myself until recently. In the future, please just ignore it rather than berating someone for trying to help.

Sometimes it takes thinking outside the box to figure something out... I was merely trying to rule out other things before assuming you did something wrong during construction.

I've heard of woofers getting a slight boost in db/W after loosening up a bit. My thinking was if that is the case, then maybe it will raise it up to the tweeter level a bit. But you are right, probably not enough for what you are seeing.

My second statement was about potential for something mechanically wrong causing the reported distortion. It can come in and out and can be hard to detect audibly, especially if something else is grabbing your attention like the boosted HF. But it seems the distortion has been figured out.

[joshshetter]

Apologies DrewsBrews.

Looks like I'll be taking the speakers up to PE office to be analyzed, should be a fun trip.

[joshshetter]

Hey guys, hope everyone has a good weekend, mostly just rain here.

I was about to run a c-note up to PE, wanted to measure again just to make sure they're still wonky. I 'm wondering if my results could be from my measurement process. I noticed I got a big HF tilt when pointing the mix on axis vs. at the ceiling. I'm thinking this might have been my fault all along, whoops.

Orange is pointed at ceiling, teal is pointed at tweeter, taken in room.

[billfitzmaurice]

You don't have to point the mic at the ceiling but it should be aimed 90 degrees off-axis. Aiming at the ceiling does that, as does at the floor or to either side, or any of some 356 other one degree increments of rotation. Just as important is to take measurements outdoors, so that you're only measuring the speaker and not the room.

[Chris_Perez]

Thanks so much Chris. I'm hopeful we can figure it out.

Hello Josh,


I went ahead and took measurements of the ND25FW-4 tweeter and there has been pretty much no significant change between the golden sample (from 2015) and our current stock (manufactured in 2022).
Here is the results of the measurements:
Red = Golden Sample (2015)
Black = Unit from 10-2019 stock
Blue = Unit from current stock


​It is doesn't appear that the issue is caused by the tweeter.

[Chris_Perez]

Hey guys, hope everyone has a good weekend, mostly just rain here.

I was about to run a c-note up to PE, wanted to measure again just to make sure they're still wonky. I 'm wondering if my results could be from my measurement process. I noticed I got a big HF tilt when pointing the mix on axis vs. at the ceiling. I'm thinking this might have been my fault all along, whoops.

Orange is pointed at ceiling, teal is pointed at tweeter, taken in room.

Now that is more like what I would expect.
I think you are on the right track.

-Chris P

[a4eaudio]

If it's your measurement setup maybe you should describe that in detail. My first time measuring I had a laptop that had some kind of audio processing I could never override (it was a work laptop and I didn't have all the admin rights I needed). I spent weeks trying to measure and kept getting really odd results until I tried using my wife's Mac Book.

[joshshetter]

Hey Chris, I don't think your images are loading in your comparison post of new and old tweeters.

I took these outside yesterday just to get the room out of the equation. I live close to a highway so it can be hard to get really accurate results. I do find that the speakers are quite annoyingly bright in my decently treated room, I find them effectively un-listenable without -4db HF shelf starting at 7500khz. I have them positioned about 2" from the rear wall. Perceptually what I hear seems closer to the Purple trace below and not so much like the orange. Not sure if I just have a very strong preference for reduced HF energy or not. I've got to pick up some horns from PE so I'm not opposed to dropping off a speaker to test anyway if my listening impressions seem off.

Orange - mic 90 degree
Purple - mic straight at speaker
Green - Raw tweeter mic 90 degree

[rpb]

For a few bucks, you could add the notch filter I suggested in post #26.

[Chris_Perez]

Hey Chris, I don't think your images are loading in your comparison post of new and old tweeters.

Thanks for the heads up. Not sure what I did wrong there, lol... but it should work now.

-Chris P

[joshshetter]

Thanks for the verification on the tweeter, looks pretty damn consistent. Mine measure pretty much identically. So this just makes me wonder, was the speaker intended to be this bright?

I went ahead and tried the filter RPB suggested, pretty much fixed the brightness for me. These are both with mic pointed straight at tweeter. Blue is without filter. Sounds much more tonally correct now, no more need for digital filters to tame the top end.

[DrewsBrews]

I point my mic directly at the drivers and the resulting speaker doesn't seem overly dull in the HF after designing them for a level response. Normal recordings sound normal.. Bright recordings still sound bright. Maybe I'm bright sensitive. Every photo I remember seeing has the mic pointed straight at the drivers/baffle. What am I missing?

I put the factory files into PCD and am trying to omit parts as if there are bad solder joints somewhere. The only way I can get a slope as extreme as you are seeing is with all the parts omitted from the tweeter except for one of the 2uf caps in series.

[joshshetter]

I point my mic directly at the drivers and the resulting speaker doesn't seem overly dull in the HF after designing them for a level response. Normal recordings sound normal.. Bright recordings still sound bright.

I wasn't really getting that at all, everything sounded very, very bright. When compared to some genelec 8030c, the cnote just sounds way too bright, and these speakers should both be pretty neutral. They sound like if you made a speaker with the tweeter too loud. I'd still like to drop them off at PE and see what they say. Can always just use my classix II in the meantime.

[DrewsBrews]

I think you misinterpreted what I was saying. I've just not heard of the 90deg thing being a norm.

I design the speaker response to be level when the mic is pointed directly at them. Yours are showing the rise when the mic is pointed directly at it. If they sound bright but measure flat when the mic is at 90deg from the speaker then that tells me that is not the correct method of measurement. Trust your ears to tell you which measurement is more accurate.

[joshshetter]

Dropped one cnote off at PE, figured it was going to be the easiest way to figure out what's wrong, be it speaker or measurement setup. Store staff is always a pleasure to interact with.

[joshshetter]

Here's PE's in house measurements, I'm guessing my measurement mic might have some issues? I still find these speakers to be pretty dang bright. I have been wanting to build a three way speaker and I might just use the drivers from this kit, add a peerless sls 10" and work out a xover, although I think I might need a new mic.

Red trace is my speaker, mic was 1m away pointed on axis according to PE. I had it a little overstuffed so I lost some output on the woofer, I am also not using the stock port length at the moment. Makes me want to pull some extra stuffing I have in a few other projects I have that might be overfilled.

Thanks PE folks, Chris, Andrew, and Doug for spending your time to help me on this one.