Measuring Some Vintage Speakers

[laserluxxer]

Cool!
I'll start with JBL L19, so the home variant of the 4301.
I meassured them outside on my terrace with a calibrated behringer ecm8000.

Unfortunately i dont have the original meassurements anymore so i cant scale them to a 50db range.
First Horizontal plots.
0-90° Green is 180° behind the speaker

verticals

So all in all, good horizontals with a lot of off axis energy up to 18k. verticals are as expected but one could find thousands of modern speakers with similar DI.
imo the le25/26 tweeter is quiet impressive. A cone that keeps its directivity to 18khz is something to behold.
in general i think the L19 very impressive for the time and not really outdated in the consumer market.

 

[laserluxxer]

And a second one.
Phillips 541 MFB
So active speakers with motional feedback woofers from the 70s.

Horizontals meassured to one side. Of course the speaker will meassure assymetrically but i dont think its too important.
More important is the bad tweeter. The mfb woofer is working great with -10db at about 40hz in closed box but the tweeter is just a resonator. lol
But the good bass extension in combination with no port resonances make these speakers sound pretty good.
This speaker shows great how lower frequencies are subjectively more important then the high frequencys.

 

[DanielT]

Cool!
I'll start with JBL L19, so the home variant of the 4301.
I meassured them outside on my terrace with a calibrated behringer ecm8000.

Unfortunately i dont have the original meassurements anymore so i cant scale them to a 50db range.
First Horizontal plots.
0-90° Green is 180° behind the speaker

verticals

So all in all, good horizontals with a lot of off axis energy up to 18k. verticals are as expected but one could find thousands of modern speakers with similar DI.
imo the le25/26 tweeter is quiet impressive. A cone that keeps its directivity to 18khz is something to behold.
in general i think the L19 very impressive for the time and not really outdated in the consumer market.

Good job with the measurements. Fascinating with as you say:..good horizontals with a lot of off axis energy up to 18k.

And a second one.
Phillips 541 MFB
So active speakers with motional feedback woofers from the 70s.
View attachment 362206
Horizontals meassured to one side. Of course the speaker will meassure assymetrically but i dont think its too important.
More important is the bad tweeter. The mfb woofer is working great with -10db at about 40hz in closed box but the tweeter is just a resonator. lol
But the good bass extension in combination with no port resonances make these speakers sound pretty good.
This speaker shows great how lower frequencies are subjectively more important then the high frequencys.

View attachment 362207

Tip:

Motional Feedback (MFB)?

It seems to be a smart system, right? Common in constructions nowadays? In the art of audio sound reproduction it is well-known that the dynamic loudspeaker is more nonlinear and generates more distortion than all the other system components combined. This is particularly true at low...

audiosciencereview.com

 

[Rick Sykora]

Given different measurement gear and conditions, serious comparisons between speakers will be problematic. Even if just for fun, using common (50 dB) scale and smoothing would help. As most know, lower bass measurements will be most dependent on conditions, so even more critical to indicate how they were done.

p.s. also please state measurement axis AND distance

 

[thewas]

And a second one.
Phillips 541 MFB
So active speakers with motional feedback woofers from the 70s.
View attachment 362206
Horizontals meassured to one side. Of course the speaker will meassure assymetrically but i dont think its too important.
More important is the bad tweeter. The mfb woofer is working great with -10db at about 40hz in closed box but the tweeter is just a resonator. lol
But the good bass extension in combination with no port resonances make these speakers sound pretty good.
This speaker shows great how lower frequencies are subjectively more important then the high frequencys.

View attachment 362207

I have their bigger 3-way siblings, the 587:

Here are windowed measurements of both after the repairs and adjustments, perfect linearity better than +-2 dB and superb matching better than 0,5 dB:

Even their directivity isn't too shabby thanks to the small mid and high domes with even some kind of waveguide:

 

[Rick Sykora]

I have their bigger 3-way siblings, the 587:

View attachment 362248

Here are windowed measurements of both after the repairs and adjustments, perfect linearity better than +-2 dB and superb matching better than 0,5 dB:

View attachment 362254

Even their directivity isn't too shabby thanks to the small mid and high domes with even some kind of waveguide:

View attachment 362255

Nice, what did you consider to be measurement axis?

 

[thewas]

Nice, what did you consider to be measurement axis?

Horizontally the (offset) center of the mid and tweeter.

 

[Tassin]

Given different measurement gear and conditions, serious comparisons between speakers will be problematic. Even if just for fun, using common (50 dB) scale and smoothing would help. As most know, lower bass measurements will be most dependent on conditions, so even more critical to indicate how they were done.

p.s. also please state measurement axis

It might be useful to set some standards that we can adhere to, before we have a proliferation of settings.
I'll leave it up to the more experienced among you to take the lead.

 

[bconline]

I'll start with JBL L19, so the home variant of the 4301.
I meassured them outside on my terrace with a calibrated behringer ecm8000.

Thanks for posting! Glad you did the horiz and vert angles.

 

[laserluxxer]

i also think 50db scaling is advisable but to be honest all this doesnt really matter imo.
Standarts are nice if one wants to check if a manufacturer is lying but these speakers are 30 years out of service and nobody has a reason to "market" them.
all these measurements show the charactaristic of the speaker and if they have faults or not.
The JBL L19 is obviously a good bookshelf two way.
The Phillips 541 partly but the well known tweeter isnt so good which shows.
The Phillips 587 is a very good dome 3way, with the tweeter breaking up at 18k because of the diffuser.
The JBL L100 isnt. And so on.
One can not overlay them but one can tell the difference between good and bad without a doubt.
I made the ref axis meassurements for the L19 and never afterwards because i dont see a reason. I dont need nfs like meassuements.

Thats a comparison of 3 different 0° positions. whats best?

The speakers are meassured at about 2m height in my garden so the base response is somewhat comparable to free field. Differences between closed box, reflex, cardioids and so on can easily be seen.

 

[Rick Sykora]

i also think 50db scaling is advisable but to be honest all this doesnt really matter imo.
Standarts are nice if one wants to check if a manufacturer is lying but these speakers are 30 years out of service and nobody has a reason to "market" them.
all these measurements show the charactaristic of the speaker and if they have faults or not.
The JBL L19 is obviously a good bookshelf two way.
The Phillips 541 partly but the well known tweeter isnt so good which shows.
The Phillips 587 is a very good dome 3way, with the tweeter breaking up at 18k because of the diffuser.
The JBL L100 isnt. And so on.
One can not overlay them but one can tell the difference between good and bad without a doubt.
I made the ref axis meassurements for the L19 and never afterwards because i dont see a reason. I dont need nfs like meassuements.

Thats a comparison of 3 different 0° positions. whats best?

The speakers are meassured at about 2m height in my garden so the base response is somewhat comparable to free field. Differences between closed box, reflex, cardioids and so on can easily be seen.

I can acknowledge that you may be able to discern value in your own relative measurements, but without measurement conditions, nothing you supplied should be judged by others meaningfully. So, for fun, maybe. But, at 120 dB scale, can make a turkey fart look flat. 

Are you really measuring at 105 dB?  If so, hope you are wearing hearing protection.

You might own have the next best thing to a Klippel, but the results may be interesting (but not very relevant) without knowing the conditions.

It is not much more work, but the discipline of stating conditions is the science ASR is built upon. Please do not take this personally as the same standard applies to any and all (even if it seems I singled out your post).

 

[bconline]

From what I know the original 4311 crossover has one attenuator and one capacitor for the midrange driver and also another such pair for the tweeter.

Yup. That's all there is to it.

 

[laserluxxer]

I can acknowledge that you may be able to discern value in your own relative measurements, but without measurement conditions, nothing you supplied should be judged by others meaningfully. So, for fun, maybe. But, at 120 dB scale, can make a turkey fart look flat. 

Are you really measuring at 105 dB?  If so, hope you are wearing hearing protection.

You might own have the next best thing to a Klippel, but the results may be interesting (but not very relevant) without knowing the conditions.

It is not much more work, but the discipline of stating conditions is the science ASR is built upon. Please do not take this personally as the same standard applies to any and all (even if it seems I singled out your post).

I understand the general direction where this is going and i think its great to push manufacturers to adhere to standarts, but i think its a big difference between me an a manufacturer.
There is no incentive for me to have the meassurements look better then they are. You can see the relation of the angled meassurements and can judge for yourself if this is a good design for the 70s or not. Thats why the ripple isnt smoothed out.
Levels are not calibrated because i dont need to. I dont need to know how much spl the speaker does at 1W. Much more important to adjust the level relative to the noisefloor when meassuring outside.
I cant meassure at 1W outside because of the noisefloor so why bother calibrating?
Why bother building a motorized stand to get the angles within+-1° if deviation is maybe 0,5db?
And where does this end? Do you know how much it costs to build a stand where the ref axis of the speaker is the rotational axis?
Making a mic arm and speaker stand which has lower diffraction?

Like i said standarts are nice for marketing but not neccesary for engineering. These are official Eckmiller O15 Meassurements. I think it was possible to make usefull meassurements before the cta2034 standart.
My meassuring conditions are "outside on a stand" which was stated on the first post and anyone who does meassurements know what this means. I also acknowledged the scaling beforehand but its still usable because of the format and the way rew scales.

 

[laserluxxer]

Ok so now something very interesting.
ME Geithain ITS 100

so 2x 8" woofers with gigantic magnets, cardioid enclosures and a 28mm tweeter with horn and diffraction lens.
Compression drivers were not available in east germany so this was a pretty smart move even though not perfect.

Horizontals including 180° meassurement:

Verticals:

So for a 80s east german pa speaker crazy good horizontals, obviously wild verticals, a huge 13k dip beacause of the lens in front of the tweeter and constant 10db rear rejection below 1k.
I have to say, they really sound great at big listening distances, which is their intended usecase.

 

[ferrellms]

Wow, that is incredible amount of work. I promoted it to home page.

Interesting, thanks.

 

[DanTheMan]

Sure! I'd love to see measurements of other vintage speakers.

Does that stand for me as well? I’ve really only done one recently.

 

[bconline]

Does that stand for me as well? I’ve really only done one recently.

Sure! Show us what you did!

 

[DanTheMan]

I have a set of Bose 201 series IV laying around but the upper mids and treble always sounded off. I found measurements online which explained it so I thought I'd see what replacing the tweeter would do. Here's the replacement which does make for a smoother response at the woofer axis. The measurements still resemble the measurements I found in several key ways and ultimately are slightly more balanced overall than with the new tweeter so I did a little experimentation. Graph should say "woofer Axis". First reflection gated out at 7ms.

I'll try to explain the other graphs where necessary. This is the Averages of the speaker rotated horizontally in approximately 12.5 degree steps across the front toward the tweeter:

Reverse polarity tweeter:

Not the tweeter axis as it's 15 or 20 degrees off axis with the woofer, but the woofer's axis/tweeter height:

Woofer only:

Tweeter level EQ development:

Now to get to work really fixing this thing. Oh, pardon my amplifier as it starts rollin off slightly at 12kHz and dramatically 50Hz (not demonstrated).

 

[DanTheMan]

The measurements I found online were here: https://diy.midwestaudio.club/discussion/770/bose-201-series-iv
the correlation is pretty close when you consider the tweeter change.

 

[bconline]

I acquired another vintage speaker - Sonus Faber Concertino. 20+ years old. 5.5" woofer and 3/4" silk dome tweeter. Beautiful leather and piano black cabinet. For consistency with prior measurements, here's the graph measured under the same conditions.