Even back in the days when we designed crossovers using paper and pencil, it was know what had to change and what had to stay the same in order to make fair comparisons
.
- So I came across some reading suggesting that the anomalies seen starting around 10khz are the result of a mismatching of exit angle to horn. Very glad that the jbl 2451 is throatless.
Yes, those are driver related. The STX that zjagaya used is a made in China, low budget driver. Definitely not comparable to your JBLs.
These plots of the E-JMLC 1000 were made by using a BMS 4538.
No anomalies here:
An externally hosted image should be here but it was not working when we last tested it.
An externally hosted image should be here but it was not working when we last tested it.
Last edited:
JMLC-200T with BMS 4590.
The ripples as well as the narrowing in the top octave are also driver related.
The ripples as well as the narrowing in the top octave are also driver related.
An externally hosted image should be here but it was not working when we last tested it.
It can definitely be a problem and why I align honed plus other tweaks to smooth out some Altecs, but the JBL has worse responses than what I started with, so seems a pretty significant connection problem when it looks this jittery on a PWT: https://www.jblpro.com/pub/components/2451.pdf
GM
Last edited:
More Mud
PWK qualified and quantified it a long time ago. See attached "Mud Factor" article. WHG
Yeah, actually I see quite a lot of babbling in that
PWK qualified and quantified it a long time ago. See attached "Mud Factor" article. WHG
If it was a point source, but its extreme HF is being squeezed/homogenized through a phase plug, so seems reasonable that it's the area between the phase plug/throat where it all goes awry, so don't see how Aquaplas is going to help this high up.
For sure, back in the day when we were experimenting with Dammar, shellac, lacquer hair spray, etc., we could really change the mid-band, but when we damped the surrounds where the extreme HF originated, it was an 'all or nothing' change, which some folks preferred and added super tweeters.
GM
For sure, back in the day when we were experimenting with Dammar, shellac, lacquer hair spray, etc., we could really change the mid-band, but when we damped the surrounds where the extreme HF originated, it was an 'all or nothing' change, which some folks preferred and added super tweeters.
GM
Interesting article, thank you for posting.
Admittedly, I have my doubts about modulation distortion being a major issue with the "heavy duty drivers" such as the B&C 15NBX100 & 15TBX100.
I do think the "acceleration factor" matters.
Frequency modulation distortion is present anytime a wide band device is asked to simultaneously produce low and high frequencies, and cone excursion is significant.
It does not matter if the cone is light duty or heavy duty.
BL/Mms:
B&C 15NBX100: 151.9
B&C 15TBX100: 140.8
Altec 416-8B: 252.8
Correct, that's what I forgot in my previous post: excursion.
mabat referred to mid frequencies > not requiring any excursion to speak of.
However, it's about reproducing the mids and the lows at the same time.
The question remains whether modulation distortion is significantly (or relatively) higher in the heavy coned, large Xmax drivers (also playing mids, which they weren't designed for).
B&C 15NBX100: 151.9
B&C 15TBX100: 140.8
Altec 416-8B: 252.8
Correct, that's what I forgot in my previous post: excursion.
mabat referred to mid frequencies > not requiring any excursion to speak of.
However, it's about reproducing the mids and the lows at the same time.
The question remains whether modulation distortion is significantly (or relatively) higher in the heavy coned, large Xmax drivers (also playing mids, which they weren't designed for).
Correct.I have read that going from a 2-way speaker to a 3-way can lower modulation distortion by as much as 10 dB for the same acoustic output, but I cannot cite the source of that information, though it was reputable.
And that's the BIG trouble, but a lighter moving system won't help you for a better midrange in that case (typically) - that's what I meant. There's just no reason it should sound any better. It may be easier to implement, to that I agree.
Higher currents in the coil, higher inductance [ Le (i) ] can be problematic. While the driver may be used in the pistonic region with a stiff cone, gains in one area may be offset by losses in others.
Audio is all about trade-offs.