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JBL Stage A130 Review (speaker)

Presently42

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Ok he just ordered them. Fingers crossed
I love mine, and am super happy I got them. Even without eq, they sound great, and I'd be very happy owners without. Any reason you can't connect a raspberry pi or even an analogue eq to them?
 

Chromatischism

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I'm having trouble with the highest recommendation here. Yes, I understand these are a bang for the buck type of speaker, but just looking at the objective measurements:

Based on the frequency response, distortion, and directivity, this is a good speaker - but not a great speaker. It gets a little shouty in the 1-2 kHz range and the directivity gets wonky in the high frequencies, and that cannot be fixed. Wall reflections will be different as they bounce back to you and if you have listeners to your sides they will hear the top end differently than you, so the sweet spot isn't huge. Clearly the waveguide is not optimal. Yet, there are speakers that measure objectively better that don't get glowing recommendations.
 
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abdo123

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I'm having trouble understanding the highest recommendation here.

Based on the frequency response, distortion, and directivity, this is a good speaker - but not a great speaker. It gets a little shouty in the 1-2 kHz range and the directivity gets wonky in the high frequencies, and that cannot be fixed. Wall reflections will be different as they bounce back to you and if you have listeners to your sides they will hear the top end differently than you, so the sweet spot isn't huge. Clearly the waveguide is not optimal. Yet, there are speakers that measure objectively better that don't get glowing recommendations.

you forgot that these go for ~170$ a pair and sounded (according to Amir) as good as his Salon 2 with EQ.

The Data is objective, the recommendation is up to Amir's experience at that day and moment.

Wall reflections will be different as they bounce back to you and if you have listeners to your sides they will hear the top end differently than you

I don't know what you're talking about as this has not been my experience at all and you're not making much sense.

this is my 11 measurements spacial average (each measurment is ~40 cm away from the next), it's +/- 1 dB above the transition frequency.

Ignore the Dirac target curve, this is not a speaker with an obvious downward tilt.

1623912413075.png
 
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John Atkinson

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I didn't realize it, but @John Atkinson reviewed the A170 and mentioned this resonance issue. He said it might not be audible though. Maybe he has some comment to share here?
https://www.stereophile.com/content/jbl-stage-a170-loudspeaker-measurements

In general, the audibility of a resonance will depend on the radiating area affected by the resonance and the lower the Q (Quality Factor) of a resonance, the more likely it will have audible effects.

The rule of thumb with resonances is that they need be excited by the same number of cycles of their center frequency as their Q to reach full amplitude. The Q of the JBL 170's enclosure resonance is very high. Its frequency is 254Hz so if its Q were 400, a sustained tone at 254Hz would need to be maintained for around 1.5 seconds. This would be infrequent in recorded music, especially as 254Hz lies between the frequencies of two musical notes: B3 at 246.94Hz and C4 at 261.63Hz.

John Atkinson
Technical Editor, Stereophile
 

pjug

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In general, the audibility of a resonance will depend on the radiating area affected by the resonance and the lower the Q (Quality Factor) of a resonance, the more likely it will have audible effects.

The rule of thumb with resonances is that they need be excited by the same number of cycles of their center frequency as their Q to reach full amplitude. The Q of the JBL 170's enclosure resonance is very high. Its frequency is 254Hz so if its Q were 400, a sustained tone at 254Hz would need to be maintained for around 1.5 seconds. This would be infrequent in recorded music, especially as 254Hz lies between the frequencies of two musical notes: B3 at 246.94Hz and C4 at 261.63Hz.

John Atkinson
Technical Editor, Stereophile
Thank you. This is interesting. How are you estimating Q? It looks to me like the FWHM is something like 25 Hz, so then Q would be one the order of 10 (using Q = f/bandwidth). I must not be looking at it correctly?

Edit: also found this relationship here: http://spiff.rit.edu/classes/phys283/lectures/forced_ii/forced_ii.html#def

1623940349280.png

This reduces to Q = pi*f*tau so if tau (time constant of the decay) is something like 35msec (from your Stereophile decay plot) then I get Q is roughly 25 to 30.
 
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Teeter

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@muad The Stage A 130 were to neutral, you might say, for me, and should fit the bill for your father and many others. I had them for 3 months usage and went back to my previous, having more dynamics to my ears, when required. I watch DD movies and seldom music.
 

John Atkinson

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This is interesting. How are you estimating Q? It looks to me like the FWHM is something like 25 Hz, so then Q would be one the order of 10 (using Q = f/bandwidth). I must not be looking at it correctly?

I was quickly eyeballing it. Your estimate of the Q is probably correct.

John Atkinson
Technical Editor, Stereophile
 

More Dynamics Please

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@muad The Stage A 130 were to neutral, you might say, for me, and should fit the bill for your father and many others. I had them for 3 months usage and went back to my previous, having more dynamics to my ears, when required. I watch DD movies and seldom music.

Much appreciated that you would take the time to further explain that you were primarily using the A130 for movies and not music.
 

pjug

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I was quickly eyeballing it. Your estimate of the Q is probably correct.

John Atkinson
Technical Editor, Stereophile
I like that you do the cabinet vibration measurement in some of the reviews. Even though it seems somewhat a mystery what conclusions to draw, and I am still not sure whether I am hearing something with the A130 or imagining it. For me, these kinds of cabinet resonances do raise a flag to a certain extent, and with hindsight I would have bought a different speaker. Even though these A130 are just fine for where I have them.
 

Ralferator

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I like that you do the cabinet vibration measurement in some of the reviews. Even though it seems somewhat a mystery what conclusions to draw, and I am still not sure whether I am hearing something with the A130 or imagining it. For me, these kinds of cabinet resonances do raise a flag to a certain extent, and with hindsight I would have bought a different speaker. Even though these A130 are just fine for where I have them.

why don't you brace the cabinet a bit? Should be really easy and lower the cabinet resonances
 

pjug

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why don't you brace the cabinet a bit? Should be really easy and lower the cabinet resonances
You mean internally or on the outside? I doubt I would do internal bracing but I might be willing to brace the outside and make some measurements for comparison. Have you done this before to suggest a good way to do it?
 

Ralferator

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You mean internally or on the outside? I doubt I would do internal bracing but I might be willing to brace the outside and make some measurements for comparison. Have you done this before to suggest a good way to do it?

I would do it internally. This is how a very famous bass cabinet company does it. Just a few pieces of 12-15mm mdf glued in like this should already help a lot. Since the JBL Stage A130 are not very wide top and bottom should not have very much of resonances, so maybe one piece left and one piece right for the front and the back each would already be good enough. At least that's what i would try
 

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pjug

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I would do it internally. This is how a very famous bass cabinet company does it. Just a few pieces of 12-15mm mdf glued in like this should already help a lot. Since the JBL Stage A130 are not very wide top and bottom should not have very much of resonances, so maybe one piece left and one piece right for the front and the back each would already be good enough. At least that's what i would try
I don't have the speakers with me to look at them, but I think this would be a chore. The mid-woofers are not attached by screws so I don't want to try to remove them. I think the only easy way inside is through the terminal plate on the back, which I remember as not very large. Anyway, more than I want to try to do but thanks anyway for the suggestion. Maybe at some point I will see if clamping some panels to the outside seems to do anything.
 

John Atkinson

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like that you do the cabinet vibration measurement in some of the reviews. Even though it seems somewhat a mystery what conclusions to draw. . .

My vibration measurements are qualitative but not quantitative - they tell you what's present and at what amplitude but not how audible. Some years ago I did buy a small scientific accelerometer and tried analyzing the vibrational behavior in a matrix of points on each surface, with the idea of then being able to use Finite Element Analysis. However, attaching the accelerometer damaged the enclosure's veneer, which made it not an option for reviews where the goal is to return the review samples in as-new condition. :-(

John Atkinson
Technical Editor, Stereophile
 

pjug

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My vibration measurements are qualitative but not quantitative - they tell you what's present and at what amplitude but not how audible. Some years ago I did buy a small scientific accelerometer and tried analyzing the vibrational behavior in a matrix of points on each surface, with the idea of then being able to use Finite Element Analysis. However, attaching the accelerometer damaged the enclosure's veneer, which made it not an option for reviews where the goal is to return the review samples in as-new condition. :-(

John Atkinson
Technical Editor, Stereophile
Thanks again. Is your film device something like the cheap MEAS ones (I think I have a few of those somewhere). Did you make some sort of preamp for it?
1623958489563.png
 
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