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JBL Stage A130 Review (speaker)

pjug

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I got the JBL A130 this week. Here are my JBL A130 measurements and crossover mod I did.
The crossover is as simple as it get, and after playing with crossover optimization the end result is a very simple mod adding one 3.3 ohm resistor in serial with the Woofer capacitor.The mod results with the simulation and actual measurements looking very promising.
Please find the attach pictures of the circuit the simulation and the actual measurements before and after the mod.
The measurements are done on tweeter axis 0.5m from the speaker. It looks like the distortion in the 0.5-2KHz also improved.
At $179 I couldn't resist ordering a pair of these. Now I am intrigued by the crossover mod. How hard is it to get to the crossover PCB?
 

ObjectAudio

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Pjug,

It is easy. The crossover is attached to the speakers terminal plate on the back. Removing the speakers terminal plate with the four screws will give you the ability to acess the crossover and do the mod. Please find the attached picture.
 

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  • A130 Crossover mod.jpg
    A130 Crossover mod.jpg
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pjug

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Pjug,

It is easy. The crossover is attached to the speakers terminal plate on the back. Removing the speakers terminal plate with the four screws will give you the ability to acess the crossover and do the mod. Please find the attached picture.
Nice! In that case I have to try it!
 

pjug

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@ObjectAudio
I used VituixCAD curve tracing tool to get text files for your in room curves and Amir's klippel measurement. Then I took the difference between your orig and mod room curves, and added that to Amir's currve to get an expected result with the mod. Does that seem valid? Here is the result. Do you think the resistor value could be a little larger to suppress the midrange rise slightly more? Or, if that bump is caused by a port resonance, maybe tweaking the port might give additional improvement?
1611770561357.png
 
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pjug

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Pjug,

The plot for the adjusted ASR measurements after the mod should be:
View attachment 108847
Thanks, that looks really good. I ordered the 3.3 ohm resistors.
I think I will also experiment with the port to see if any of those two bumps below 2000 Hz can be reduced, even though they look pretty harmless after the mod.
 

Hiten

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Thanks everyone for doing these mods. looks interesting.

While the peaks below 2khz get smaller, there are now peaks at around 3-4khz?
newbie alert :
May be, but difference is small, The inroom response shown in the first post will probably make it insignificant but comparatively the mid peaks will be tamed so I guess it is a good compromise.

Will some eq. mods (hardware based ) at line source be better option ? Something like a buffer between source and the amplifier and buffer will have passive attenuation ? or a simple attenauation ?
thanks again
regards
 

Ralferator

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Thanks everyone for doing these mods. looks interesting.


newbie alert :
May be, but difference is small, The inroom response shown in the first post will probably make it insignificant but comparatively the mid peaks will be tamed so I guess it is a good compromise.

Will some eq. mods (hardware based ) at line source be better option ? Something like a buffer between source and the amplifier and buffer will have passive attenuation ? or a simple attenauation ?
thanks again
regards

It's true - in the measurements they look more balanced after the mod. I guess it's worth trying.
 

BYRTT

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For Stage A130 owners with unlimited DSP such as Roon/Foobar/Jriver players here is 20 times PEQ filter string based on Amir's anechoic analyze that will smooth out most patterns, EQ policy is based on DI curve (directivity index) so not in favor of close nearfield super flat on axis but optimal at farfield 2 meter and up as for spinorama standard (CEA/CTA-2034 ANSI)..

EQed_0_EDIT.png


Overlaid animation of detailed synthetic prediction for above EQ string based Amir's analyze..
EQed_1_x1x2_1000mS.gif
 
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Zopiac

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Just got mine in today, replacing my LSR305s of some years for near field (can't stand the amp tweeter hiss, even though it's only audible late at night with snow dampening outside noises). As an amateur first impressions, they're certainly pretty good, especially for $180 ($150 renewed that I didn't see until I hit purchase - doh!). Percussion, especially snare and high tom hits have quite the punchy impulse, I notice, but male vocals seem sort of pushed to the background. Easy listening, though, and not very fatiguing. I was worried about the 15kHz peak but I don't think my ears can hear that so well any more, for better or worse. Probably just enough for some "sparkle". Switching back to the 305s they sound a bit nasally but more fleshed out, and back to the A130s it's a bit more warm but it sounds like something's missing.

Novice measurements are attached comparing the two speaker sets, as free-field as I can make them in a large, well-padded room at 0.5m and windowed -- I couldn't get any reasonable bass figures. Once it's not so snowy outside I may try ground plane shenanigans.

I also have some 3.3Ω resistors on the way for the crossover hack to see if the midrange can be smoothed out a little. I could technically do it with on-hand components, but I'd feel dirty putting quarter watt resistors in these even for my tendency towards low level listening. Will post my findings regarding that, and perhaps give some more comprehensible thoughts on pair as a whole once they have some more hours in them.

Cheers for the detailed review, Amir!

305 vs 130.png
 

pjug

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While the peaks below 2khz get smaller, there are now peaks at around 3-4khz?
I did @ObjectAudio 's mod, and in my case there does not seem to be any boost at any frequency, just reduction. In the lower plot (mic very close to the woofer), you can see the smoother rolloff in the woofer between 700Hz and 2KHz. The upper curves are measurements at 10 inches distance. Many thanks to @ObjectAudio this is a great fix and very easy to do.
1612380430887.png
 

Ralferator

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I did @ObjectAudio 's mod, and in my case there does not seem to be any boost at any frequency, just reduction. In the lower plot (mic very close to the woofer), you can see the smoother rolloff in the woofer between 700Hz and 2KHz. The upper curves are measurements at 10 inches distance. Many thanks to @ObjectAudio this is a great fix and very easy to do.
View attachment 110393

Nice - did you listen to the speakers before and after the mod? How would you describe the difference?
 

pjug

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Nice - did you listen to the speakers before and after the mod? How would you describe the difference?
I listened some before the mod but not after yet. I have them at work at the moment where they were sitting around while I waited for the resistors. I wouldn't trust any thoughts I have now on differences I think I might hear.
 

Zopiac

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Thanks to the dangerous combination of boredom, curiosity, and impatience, I decided to string up three 1Ω resistors while waiting for the 3.3s to arrive, and test with that. But it quickly got out of hand as I measured 1, 2, 3...6, 10, and 20 Ω additions to the crossover, just to see if something awful would happen. As it turns out, one of my A130s ("B") benefits a good bit more from the added parallel resistance than the other ("A")! Overall what this is telling me is that the value isn't terribly critical, and with QC/variance between speakers some experimentation may be worth considering.

Full spread of resistance values and their changes that were taken for each speaker:
A130 A resistor mod.pngA130 B resistor mod.png

And before/after on values that I will likely aim for with the final mod:
A130 no resistor mod.pngA130 resistor mod.png

As an added bonus, the THD also flattened out for the effective range (particularly 1kHz+), although the difference between 0.4% and 0.3% at 3.5kHz is probably nothing to get too excited about. Especially considering that was on the extreme end at 20Ω. I just was worried that it may add some weird effects.
A130 B no resistor mod THD.pngA130 B resistor mod THD.png

One tweeter remains a bit hot though so I'll work on attenuating it next. Interesting that the 15.5kHz peak is pretty much bang on between the two while anything below is consistently a bit off (1.3dB from 5-14kHz). After addressing that I'll finally feel comfortable enough to leave them alone and just enjoy them... I hope.
 

pjug

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and with QC/variance between speakers some experimentation may be worth considering.
This is a good suggestion. I got lucky; measurements of my pair of A130 overlay each other almost perfectly.

I am puzzled why you and @ObjectAudio have the crossing between 2KHz and 3KHz on the orig/mod curves, whereas I am not getting that. Anyone have any ideas why?
 

Presently42

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Based on this review, I purchased the speakers for 300 cad, thanks to a post by the Canuck, who has a list of Canuckish sellers. I currently have an old pair of Technics SB-P1000 connected to an older Denon avr in a very non-suitable listening room. Eventually, I'll get a pair of f208 - but I'm hoping the a130 tide me over nicely until then! I'll post photos and measurements when they arrive.
 

pjug

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Edit: Never mind about what I write below the dashed line. I will leave it posted FWIW, but the problem was I had them on sorbothane hemispheres because the stands I'm using are kinda crappy. Sitting them flush gets rid of this problem, at least mostly. I don't like how strongly the cabinets on these speakers vibrate/resonate. I wonder if they would benefit with better padding than the minimal polyfill that they come with. Probably I will mess with all this more at some point. For now I will try putting them on a cheap mouse pad or similar.
------------------------------------------------------------------------------------------------------------------------

I am turning my attention back to these A130 in the room where I put them. Listening, they definitely sounded messed up. I ran REW and I have a nasty problem at ~230 Hz. I didn't do this same measurement, at least at the same level, before making the modification. Although at work I think I saved the measurements I did make, so I can look at those tomorrow. I can easily undo it if the mod has anything to do with this. If I play a tone at 229Hz it is bad, and if I press on the plastic around the woofer the distortion is lessened. I have this with both speakers. Anyone care to see if they have this problem, mod or no mod?

The low end is gone because I have HP filter so don't worry about that. I don't know why graph says "No smoothing", REW did that on the export.

a130 229 hz problem.jpg
 
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