Magnepan LRS Speaker Review

[Doodski]

How do you perform a listening test with one flipping speaker? Here's an idea, you don't.

Actually using one speaker removes all the special effects of the recording process and makes makes the speaker show it's true sound without room imaging effects and such. One can hear the frequency response better and determine if the speaker is distorting easier.

 

[kyuu]

How do you perform a listening test with one flipping speaker? Here's an idea, you don't.

Wrong.

 

[Newman]

How do you perform a listening test with one flipping speaker? Here's an idea, you don't.

Ah, you seem to be unaware of the research. Controlled listening tests involving comparison between different speakers show that using one speaker (instead of two) significantly improves our ability to clearly identify which speaker we prefer, including which speaker we will prefer in stereo.

Welcome to audio science, where assumptions are put to the test.

 

[Biagiod]

Ah, you seem to be unaware of the research. Controlled listening tests involving comparison between different speakers show that using one speaker (instead of two) significantly improves our ability to clearly identify which speaker we prefer, including which speaker we will prefer in stereo.

Welcome to audio science, where assumptions are put to the test.

Where assumptions are put to rest

 

[Alice of Old Vincennes]

Where assumptions are put to rest

I wish

 

[MarkS]

Ah, you seem to be unaware of the research. Controlled listening tests involving comparison between different speakers show that using one speaker (instead of two) significantly improves our ability to clearly identify which speaker we prefer, including which speaker we will prefer in stereo.

Welcome to audio science, where assumptions are put to the test.

That's a vast oversimplification of what Floyd Toole reports in his book.

To take just one example, subjective ratings of dipole speakers (BB) change much more significantly from mono to stereo than subjective ratings of forward-firing speakers (AA and E):

 

[PGansz]

Ah, you seem to be unaware of the research. Controlled listening tests involving comparison between different speakers show that using one speaker (instead of two) significantly improves our ability to clearly identify which speaker we prefer, including which speaker we will prefer in stereo.

Welcome to audio science, where assumptions are put to the test.

What kind of asinine comment welcomes someone to a forum they've been reading for years?

Next time I go to test drive a car I'll go half the speed limit see what I learn about its performance.

No one sits at home and listens to a half a speaker pair, or half a soundbar. Argue semantics all day, it's a dumb test.

 

[Newman]

What kind of asinine comment welcomes someone to a forum they've been reading for years?

I didn't welcome you to the forum, I welcomed you to audio science.

Next time I go to test drive a car I'll go half the speed limit see what I learn about its performance.

No one sits at home and listens to a half a speaker pair, or half a soundbar. Argue semantics all day, it's a dumb test.

It's not semantics, it's science.

Amir has taken the time and trouble to explain this issue. Check it out!

 

[Blumlein 88]

What kind of asinine comment welcomes someone to a forum they've been reading for years?

Next time I go to test drive a car I'll go half the speed limit see what I learn about its performance.

No one sits at home and listens to a half a speaker pair, or half a soundbar. Argue semantics all day, it's a dumb test.

And no one sits around all day doing speaker evaluation listening for enjoyment of music. If you do however want to evaluate a speaker, there are good reasons mono is more revealing than stereo. Amir has a video on that.

 

[Newman]

That's a vast oversimplification of what Floyd Toole reports in his book.

To take just one example, subjective ratings of dipole speakers (BB) change much more significantly from mono to stereo than subjective ratings of forward-firing speakers (AA and E):

View attachment 437512

And that's a vast misunderstanding of what Floyd Toole wrote in his book.

I have corrected this misunderstanding before, link. And I know you read it, since you were giving likes just a few posts upstream and downstream.

Icing on the cake, Floyd Toole has endorsed my correction.

 

[Doodski]

What kind of asinine comment welcomes someone to a forum they've been reading for years?

Next time I go to test drive a car I'll go half the speed limit see what I learn about its performance.

No one sits at home and listens to a half a speaker pair, or half a soundbar. Argue semantics all day, it's a dumb test.

It makes sense when taking into consideration the advantages.

 

[Hayabusa]

And no one sits around all day doing speaker evaluation listening for enjoyment of music. If you do however want to evaluate a speaker, there are good reasons mono is more revealing than stereo. Amir has a video on that.

Stereo imaging is surely skipped in the evaluation. I think its quite an important quality of speakers..

 

[Blumlein 88]

Stereo imaging is surely skipped in the evaluation. I think its quite an important quality of speakers..

It is dependent upon the speakers. Clearly the results show mono is more discriminating than mono. So how do you think two lesser speakers would fair better than two better speakers? The stereo testing is skipped because results indicated it was less dependable, reliable and less discriminating in other performance parameters.

It is not like speakers that have done well in the mono testing are not good in stereo. I've heard a few models that do well in such testing and they do well in stereo. Stereo to some extent dilutes differences in loudspeaker quality.

 

[Hayabusa]

It is dependent upon the speakers. Clearly the results show mono is more discriminating than mono. So how do you think two lesser speakers would fair better than two better speakers? The stereo testing is skipped because results indicated it was less dependable, reliable and less discriminating in other performance parameters.

It is not like speakers that have done well in the mono testing are not good in stereo. I've heard a few models that do well in such testing and they do well in stereo. Stereo to some extent dilutes differences in loudspeaker quality.

Conclusion: Do main evaluation in mono with a final evaluation in stereo.
Some speakers (line sources for instance) have a quite different stereo imaging than more point source speakers for instance.

 

[Blumlein 88]

Conclusion: Do main evaluation in mono with a final evaluation in stereo.
Some speakers (line sources for instance) have a quite different stereo imaging than more point source speakers for instance.

You can do that of course. Line source or panel speakers are very different from point source speakers anyway.

 

[kyuu]

Next time I go to test drive a car I'll go half the speed limit see what I learn about its performance.

No one sits at home and listens to a half a speaker pair, or half a soundbar. Argue semantics all day, it's a dumb test.

Your analogies are bad, just like your arguments.

 

[DonH56]

Stereo imaging is surely skipped in the evaluation. I think its quite an important quality of speakers..

No, stereo imaging is a function of the speakers and how smooth their response, which can be readily measured and heard from a single speaker. What is missing is the influence of your specific listening room, but even that is handled. The Klippel system also measures radiation pattern, which provides insight into how the speakers will perform in a room, once you know more about the room itself (dimensions, absorption/refection coefficients, etc.) I agree imaging is important, but you do not need two speakers to assess imaging.

 

[Moti]

Placed LRS 50cm from front wall to save space and damped back wave. Bass is weak as always but midrange sounds well. Any thoughts and pros&cons with this solution?

 

[MRC01]

Placed LRS 50cm from front wall to save space and damped back wave. Bass is weak as always but midrange sounds well. Any thoughts and pros&cons with this solution?

One good approach is to measure the bass response from the listener position several times, moving the speakers closer to or further from the front wall (behind them) to see how it changes. Use a distance that gives the most even response.

Since these are dipoles that radiate backward with inverted polarity, they boost the 1/4 wavelength frequency and cut the 1/2 wavelength frequency. Because of the inverted polarity of the back wave, this is the opposite of conventional (non dipole) speakers which cut the 1/4 wave and boost the 1/2 wave. For example, your 50 cm distance boosts the 50*4 = 2 meter wavelength which is about 170 Hz (343 m/s / 2 m = 171.5), and cuts 343 Hz.

Of course when you toe in the speakers, the effective distance to the wall is slightly increased.

Looking at your photo - foam does not damp low frequencies - for that you need physically large bass traps or tube traps. That foam behind the speakers could, however, reduce mid-treble reflections.

Another factor to consider is sound reflected from the rear wall (behind your head). The 1/4 wave frequency will have a null at your head. With dipoles, the LBIR and SBIR distances negate each other's effects, since only one of them (SBIR) has inverted polarity. So theoretically, if the distance from the speaker to the front wall equals the distance from the listener to the back wall, the reflected waves don't affect the perceived response - SBIR cuts the frequencies that LBIR boosts and vice versa. Of course, this assumes all else equal, so it is over-simplified, and room modes still have their effects.

PS: SBIR = Speaker Boundary Interference Response, LBIR = Listener Boundary Interference Response

 

[Moti]

Looking at your photo - foam does not damp low frequencies - for that you need physically large bass traps or tube traps. That foam behind the speakers could, however, reduce mid-treble reflections.

Thanks for your long reply.

LRS are really special speakers in good and bad. They are rising to the next level when below 200Hz is cut and handled by another solution. This test was done only to demonstrate midrange colouration close to front wall. I believe this is one of the main show stopper in dipole speakers in general: limited space in listening room. Perhaps the strong beaming can be adjusted also by dampening the back wave without loosing most of the sound characteristics. I have seen photos where Swiss elektrostat back wave was eliminated completely.