loudspeakers L/R matching are sometimes terrible !

[Tangband]

Hifinews are measuring the matching frequency responce accuracy of the left and right loudspeakers.

The results with loudspeakers (edit) sometimes deviate more than 4 dB in the midrange between left and right loudspeaker. Such an example are the tested JBL hdi 3800 with 4,6 dB difference.

The Paradigm founder 120h have a deviation between left and right speaker of 5,7 dB .

This is not discussed anywhere - but in my opinion theres a big problem with audible consequences and bad stereo image.

What do you think about this, and is this something that should be tested ?
Discuss

Paradigm Founder 120H Loudspeaker Lab Report

Lab Report Paradigm's very generous 92dB sensitivity rating for the Founder 120H is on the money, these flagship speakers delivering a thundering 93dB (2.83V/1kHz/1m). However, sensitivity does fall to 91.1dB across 500Hz-8kHz thanks to a loss in axial output around the 2.4kHz crossover between...

www.hifinews.com

JBL HDI-3800 Loudspeaker Lab Report

Lab Report The breakup mode of the Teonex compression driver, or its interaction with the horn throat, is clearly illustrated just outside of the audioband [pink shaded area, Graph 1] at 22kHz, rising some +15dB above the mean midband output of the HDI-3800. The CSD waterfall [Graph 2] suggests...

www.hifinews.com

B&W 702 Signature Loudspeaker Lab Report

Lab Report While the performance of the 702 Sig is broadly unchanged from the measurements published for the 702 S2 [HFN Dec 17], it is now possible to reveal some extra valuable detail. The forward response, measured on B&W's preferred midrange axis, shows the same distinctively irregular...

www.hifinews.com

B&W 801 D4 Loudspeaker Lab Report

Lab Report Rated at 90dB sensitivity, the new 801 D4 romps home with a very fine 89.7dB (1kHz) and 89.5dB (500Hz-8kHz). The forward response trend now has something of a +2dB 'step' between 100Hz-1kHz and 1kHz-20kHz [see Graph 1, below], resulting in errors of ±3.3dB from 200Hz-20kHz or ±2.2dB...

www.hifinews.com

JBL 4309 Loudspeaker Lab Report

Lab Report With that mid/treble horn front-and-centre there's hope of good sensitivity from this little box, and JBL's 4309 does not disappoint, achieving 87.8dB/1m/1kHz and 86.1dB from 500-8kHz, according well with the rated 87dB. Neither is there a sting in the 4309's tail as regards its...

www.hifinews.com

Kii Audio THREE BXT Loudspeaker Lab Report

Lab Report Although it's only one of the benefits of using DSP in an active loudspeaker, well controlled frequency response is something you expect and the Three BXT delivers. While it's possible using DSP to achieve a ruler-flat frequency response at a particular point in space, Kii Audio has a...

www.hifinews.com

A good example of matched loudspeakers are Kii audio three btx with +- 1 dB.

The Kef Blade is another exception, with apparently matched drivers and crossovers. +- 0,45 dB between L/R speaker. But this gets very expensive with passive crossovers. The bad component tolerance in many passive crossovers with +-10% differences in coils is showing up in measurements. A dsp in an active speaker can easily be reprogrammed to correct faults in every speaker, and the result regarding the dsp crossover will have a deviation much less than most passive crossovers. Theres still a selection problem with drive units.

KEF Blade One Meta Loudspeaker Lab Report

Lab Report While attention is inevitably focused on the efficacy of KEF's Meta disc in dissipating the Uni-Q driver's rear-radiation [see LS50 Meta, HFN Jun '21], the Blade One Meta's driver ensemble delivers a remarkably flat axial response [see Graph 1]. With response errors of just ±1.2dB and...

www.hifinews.com

 

[MaxwellsEq]

The BBC LS5/8 LS5/9 and even the LS3/5A were engineered and tested to be sufficiently consistent that one speaker could be switched out of a cubicle or truck and no measurement or adjustments needed when the replacement was put in. This was quite a feat of engineering.. People wax lyrical about the BBC sound, but there was also a maintainability aspect to it..
The reason I mention this is that it reflects the widely known and accepted fact that normal commercial speakers rarely match eachother perfectly, and certainly don't over the lifetime of a model's manufacturing run.

 

[Andreas007]

I don't want to think about the response curves in my living room between left and right. It is asymmetrically, speakers are not optimally placed, unwanted surfaces everywhere, etc. If I want to listen a bit more seriously I do nearfield listening with my KH120s. And it does work quite well, even under these conditions.

 

[Blumlein 88]

I wonder about their measurement consistency. I've gotten lots better than they are showing with several speakers. This according to sweeps with REW and a Umik 1. You do have to be very persnickety about exact placement of speaker and microphone.

 

[HarmonicTHD]

Just EQ any (of the small) inconsistencies. Problem solved.

 

[Tangband]

I don't want to think about the response curves in my living room between left and right. It is asymmetrically, speakers are not optimally placed, unwanted surfaces everywhere, etc. If I want to listen a bit more seriously I do nearfield listening with my KH120s. And it does work quite well, even under these conditions.

The Hifinews reviews are showing nearfield differences , - this is the most important freq. response measurement that correlate rather well with the listening impression, If you ask me . The precedence effect at listening position makes the direct sound from the speaker much more important than what the microphone is measuring at listening position. This is my experience after three years of daily measuring.

So, my point is , even If you might listen at a distance of 3 meters to the two loudspeakers, the precedence effect gonna zoom in to the first arriving sound ( direct sound from the speaker ) and you gonna hear the matching problems , higher than 2 dB in many cases, between the L and R speaker.
( Of course you know all this )

 

[Tangband]

Just EQ any (of the small) inconsistencies. Problem solved.

This can only be done below 300 Hz at listening poition .
Its possible though, If you do nearfield measurement less than one meter from each loudspeaker and have individual equalizers for each channels.

 

[Tangband]

I wonder about their measurement consistency. I've gotten lots better than they are showing with several speakers. This according to sweeps with REW and a Umik 1. You do have to be very persnickety about exact placement of speaker and microphone.

You have a point, but with the Kii and Kef blade, where attention has been taken to match the crossovers, show +- 1dB accuracy between L/R speakers. This tells me that Hifinews measurements are accurate.

 

[HarmonicTHD]

This can only be done below 300 Hz at listening poition .
Its possible though, If you do nearfield measurement less than one meter from each loudspeaker and have individual equalizers for each channels.

Nearfield is not necessarily required IMHO.

Yes two EQ channels are required, as this is a good idea anyway as many rooms are not (acoustically) symmetric. Most modern AVRs and MiniDSP and afik even some SW EQs offer individual channel EQ. So not that exotic.

 

[Tangband]

Nearfield is not necessarily required IMHO.

Yes two EQ channels are required, as this is a good idea anyway as many rooms are not (acoustically) symmetric. Most modern AVRs and MiniDSP and afik even some SW EQs offer individual channel EQ. So not that exotic.

Most AVRs dont measure individual speakers at a distance of less than 1 metre.
Good corrections with measurements from the listening position can only be done below 300 Hz, as Amirm already has shown.

 

[sergeauckland]

I've been banging on about this for a long time. The accuracy of the stereo image depends hugely on accurate matching of the frequency response, so it's an essential measurement on a pair of loudspeakers.

I've commented before that the one criticism I have of the measurements on this site is that for perfectly understandable reasons, only one loudspeaker is measured, but given that loudspeakers are used in pairs, measuring just one doesn't say anything about how good they will be when used for stereo.

Matching to +-1dB is in my view essential, especially at mid to high frequencies, and very few passive 'speakers achieve that.

S

 

[Tangband]

I've been banging on about this for a long time. The accuracy of the stereo image depends hugely on accurate matching of the frequency response, so it's essential measurement on a pair of loudspeakers.

I've commented before that the one criticism I have of the measurements on this site is that for perfectly understandable reasons, only one loudspeaker is measured, but given that loudspeakers are used in pairs, measuring just one doesn't say anything about how good they will be when used for stereo.

Matching to +-1dB is in my view essential, especially at mid to high frequencies, and very few passive 'speakers achieve that.

S

Very true

 

[HarmonicTHD]

Most AVRs dont measure individual speakers at a distance of less than 1 metre.
Good corrections with measurements from the listening position can only be done below 300 Hz, as Amirm already has shown.

All the modern Denons do.

 

[HarmonicTHD]

BTW. Kef also provides individual measurements for the Reference series not only for the Blade. I am traveling and can’t look, but think to remember it was less than 1.5dB for mine.

 

[Tangband]

JBL 4309 Loudspeaker Lab Report

Lab Report With that mid/treble horn front-and-centre there's hope of good sensitivity from this little box, and JBL's 4309 does not disappoint, achieving 87.8dB/1m/1kHz and 86.1dB from 500-8kHz, according well with the rated 87dB. Neither is there a sting in the 4309's tail as regards its...

www.hifinews.com

In this case the difference between L/R speakers are 2,4 dB in the midrange. Clearly audible.

 

[Tangband]

BTW. Kef also provides individual measurements for the Reference series. I am traveling and can’t look, but think to remember it was less than 1.5dB for mine.

Yes, the passive Kef blade is within +- 0,45 dB - very good.

 

[goat76]

I've been banging on about this for a long time. The accuracy of the stereo image depends hugely on accurate matching of the frequency response, so it's essential measurement on a pair of loudspeakers.

I've commented before that the one criticism I have of the measurements on this site is that for perfectly understandable reasons, only one loudspeaker is measured, but given that loudspeakers are used in pairs, measuring just one doesn't say anything about how good they will be when used for stereo.

Matching to +-1dB is in my view essential, especially at mid to high frequencies, and very few passive 'speakers achieve that.

S

This is something I think is overlooked and I want to see measurements of how different manufacturers do with the matching of speaker pairs. If the speakers don't match well, the stereo imaging will suffer.

 

[Inner Space]

From a post I made about a year or more ago in another thread: " ... 3 years ago was hired to do the stereo mix for a streaming series made in Hollywood. I said I would only do it in my own suite at home. Their counter was, OK, but you have to use JBL 4367s, to maintain the "house sound" (yeah, rooms, variables, etc, etc, but these are producers, not brain surgeons). We ordered 12 units from Harman and had them drop-shipped to a studio I know for testing. I wanted a pair that matched within 0.5dB for sensitivity, FR and distortion.

Only 2 of the 12 made it. Errors from one extreme to the other reached 4dB. One was 2dB less sensitive than the other 11. Ironically the "good" pair shipped onward to me were tipped up hot above the crossover, a clear error, but at least two identical errors."

Admittedly this was fairly early production, and I have to say I now have a later 4367 pair that was pretty good from new. But generally my experience has been that pair matching for passive speakers is randomly haphazard, and as @sergeauckland says above, that's a crucial problem if you want more than mono.

 

[test1223]

Hello,

you are right, this is a real problem which isn't mentioned that often.

You can hear these differences best if you places the speakers symmetrical in the room which is highly recommend anyway. A lot of set-ups didn't provide that due to asymmetrical rooms or higher priority of other things than hifi.

While active loudspeaker could theoretically be better, there are also bigger left right differences in praxis. The main problem is the tolerance of the drivers. Even an active loudspeaker often needs some manual correction where every speaker is measured in the same way. This cost time and resources and therefore money.

Cheaper driver often has to come with higher tolerances. There are some problems like the roll of of a woofer or midwoofer or the exact placement of the coul in the magnet which cause differences that are hard to overcome from the production side.

More expensive speakers are often better than budget ones since drivers and frequencies components can be made more expansive and provide a tighter tolerances. The drivers which didn't match the tolerance are often used in the cheaper models, if an in house selection is done. Therefore two random speakers of the expensive model better match.

You also have the issue with golden samples when a manufacturer provides a speaker for review. This speaker is almost certainly a speaker which measures good since it was additionally checked and choose by an engineer. Therefore the performance can be better than an average speaker from the production.

Best
Thomas

 

[Tangband]

Measurement mics on this forum is usual in a tight spec to be considered ” good enough ” . Often within +- 1 dB .

Why should one accept L/R errors between different loudspeakers as much as 5 dB in the midrange , even from very expensive brands ?

I think maybe this issue are unknown for many hifi - enthusiasts ? They see the reviews from a single good measuring loudspeaker , think its good enough for a stereo pair , when in reality , the two loudspeakers might differ up to 5 dB , which is very audible .

My guess is that no loudspeaker manufacturer wants to talk about this .
They know the problem with matching exists , but its to expensive doing the matching of passive crossovers and drivers to correct this within +- 1 dB .

( Kudos to Kii, Genelec , Neumann, Kef and others for taking this serious )