FAO the pro-measurement crowd: ASR to start measuring speaker performance

[ToTo Man]

First speaker review just published:

https://www.audiosciencereview.com/...mkii-and-control-1-pro-monitors-review.10811/

Quite informative, especially the comparison to a speaker with poorer off-axis response. It would have been good though if he'd also listened to the Control Pro 1 and shared his subjective impressions on its presentation to give readers an impression of how its much poorer measured off-axis response actually sounds in a typical listening room (or even better, two listening rooms, one with acoustic treatment and one without), if only to confirm what the measurements indicate.

PS - I'm a bit confused by the very first graph. Unless I'm misreading, the red line shows the in-room nearfield response, while the blue line shows the mathematically derived anechoic response after reflections (dashed blue line) have been removed. There appears very little difference between the two, much less than I'd have expected, in fact they're so similar I dare say the in-room response could easily be used as a proxy for the anechoic response. Why are the two so similar?

 

[ToTo Man]

Would it be fair to view polar dispersion graphs as the historical, albeit much simplified (i.e. horizontal axis only), equivalent of the spinorama? I remember many loudspeaker manufacturers of yesteryear included these as standard (for their higher end speaker models at least) along with the obligatory anechoic on-axis frequency response graph.

 

[Purité Audio]

I believe Harman coined the Term ‘ Spinorama’ some manufacturers use anechoic chambers or extremely large rooms for development, John Atkinson has used a quasi anechoic system.
Re the plots , 5DB down at 100Hz , I will ask Amir.
Keith

 

[ToTo Man]

I believe Harman coined the Term ‘ Spinorama’ some manufacturers use anechoic chambers or extremely large rooms for development, John Atkinson has used a quasi anechoic system.
Re the plots , 5DB down at 100Hz , I will ask Amir.
Keith

5dB down at 100Hz?? In the graph I linked to there's only a 2dB difference between the in-room and derived anechoic response at 100Hz.

 

[Arkless Electronics]

I'm not a member of SBAF (yet) but actually find it a pretty useful resource for headphone frequency response, CSD and distortion measurements.

First time I've even heard of SBAF! Just looked it up... weird... not sure if I'm the "type" that would be welcomed with open arms or set a new record for how quick they are banned!

 

[ToTo Man]

Just thinking aloud, I find it rather ironic that many/(most?) loudspeaker designs offer smoother and more predictable horizontal off-axis response than vertical off-axis response, yet it's the vertical axis that many listeners fail to prioritise when setting up their speakers! i.e. They obsess about toe-in and sitting perfectly central in the 'sweet spot' but often have their speakers at a suboptimal height and thus fail to achieve the most coherent response at the listening seat. There is admittedly a compromise to be struck, as optimising speaker height for the smoothest midrange/treble transition may not necessarily be the height that's most benign with respect to upper bass / lower midrange floor-bounce cancellations, etc.

 

[DimitryZ]

Just thinking aloud, I find it rather ironic that many/(most?) loudspeaker designs offer smoother and more predictable horizontal off-axis response than vertical off-axis response, yet it's the vertical axis that many listeners fail to prioritise when setting up their speakers! i.e. They obsess about toe-in and sitting perfectly central in the 'sweet spot' but often have their speakers at a suboptimal height and thus fail to achieve the most coherent response at the listening seat. There is admittedly a compromise to be struck, as optimising speaker height for the smoothest midrange/treble transition may not necessarily be the height that's most benign with respect to upper bass / lower midrange floor-bounce cancellations, etc.

That's why line source speakers rule!

 

[Yank]

First speaker review just published:

https://www.audiosciencereview.com/...mkii-and-control-1-pro-monitors-review.10811/

What a surprise that he leads off with JBL...

 

[Mullardman]

I heard speakers in Tannoy's 'anechoic chamber'. Not much to hear.

Also.. does any of this guff tell you how your speakers will sound in your room with your source and amps?

Just sayin'

 

[davidsrsb]

Poor off vertical axis response is a problem for ceiling reflections too, especially in very low UK rooms

 

[ToTo Man]

That's why line source speakers rule!

Like these?

 

[ToTo Man]

Poor off vertical axis response is a problem for ceiling reflections too, especially in very low UK rooms

At what ceiling height would you say this becomes a problem, or does it ultimately depend on listening distance? A few years ago I conducted a very unscientific experiment where I got my dad to stand on a ladder and hold a 10kg broadband bass trap as high above his head as he could in the middle of my room (halfway between my speaker and listening seat). I took an on-axis FR measurement, and then repeated the measurement with the bass trap laying on the floor. Laying the bass trap on the floor made a much larger difference to the on-axis FR measurement than holding it near the ceiling. This was in a 3.25m high room with speakers whose mid/bass drivers were around 0.9m above the floor with a listening distance of approx 2.5m.

 

[ToTo Man]

From Amir's review:

"...In addition to being smooth, the early window response sum should be similar to the direct sound. If so, then the brain doesn't think of them as unique "reflections" and "echos" and uses the information for other (positive) purposes (e.g. strengthening the volume of what you hear). If these reflections are too different, this may not happen. If you are determined to use such speakers, then you should look at absorption of these reflections (using thick, "broadband" material). That is for another topic..."

From what I understand, first reflection absorption is not intended solely as a remedy for speakers with non-linear off-axis response, it can be used to control the amount of reflected sound relative to direct sound and control room decay times irrespective of the speaker's dispersion characteristics.

E.g. Tannoy DCs are considered to have smooth off-axis response, yet mine still benefited from the addition of broadband absorption at the first reflection points (side walls) to reduce smear and improve clarity and image localisation.

 

[Purité Audio]

Magico use the same Klippel system
https://www.monoandstereo.com/

Keith

 

[davidsrsb]

At what ceiling height would you say this becomes a problem.......This was in a 3.25m high room with speakers whose mid/bass drivers were around 0.9m above the floor with a listening distance of approx 2.5m.

Most modern UK house are around 2.4m, which puts the top of the speaker close to the midpoint. Maybe this means floor and ceiling bounce tend to add. A higher ceiling like yours (or mine in KL), not just has a much higher path loss, but is more likely to not coincide with floor bounce.
I used to have a 6m ceiling and it really messed up speaker voicing as it was so far from a typical room dimension.

 

[DimitryZ]

Like these?

I owned three pairs up to 3.5R...

Great speakers, but I didn't like the wire glued to plastic construction.

Ended up with Eminent Technology 8b, because they etch away metal to make the circuit...starting with metalized plastic...very, very reliable and stable.

 

[al2002]

Another speaker test was posted earlier today:

https://www.audiosciencereview.com/...ds/nht-pro-m-00-powered-monitor-review.10859/

Not too impressive.

 

[John Phillips]

Another speaker test was posted earlier today:

https://www.audiosciencereview.com/...ds/nht-pro-m-00-powered-monitor-review.10859/

Not too impressive.

I think we may have to wait a bit for the measurements to "settle down" and build into a bigger "library" before entering into significant judgement.

When I was working in a research lab and needed to measure how something performed I would immediately set up the test kit and made measurements. But on the basis that I would always have to discard the first (or first few) measurement sets, as I learned how the test was working (or not) and learned how to make the results meaningful. But IMHO starting immediately to learn from experience is always better than delay from trying to get it right first time.

 

[AndyU]

At what ceiling height would you say this becomes a problem, or does it ultimately depend on listening distance? A few years ago I conducted a very unscientific experiment where I got my dad to stand on a ladder and hold a 10kg broadband bass trap as high above his head as he could in the middle of my room (halfway between my speaker and listening seat). I took an on-axis FR measurement, and then repeated the measurement with the bass trap laying on the floor. Laying the bass trap on the floor made a much larger difference to the on-axis FR measurement than holding it near the ceiling. This was in a 3.25m high room with speakers whose mid/bass drivers were around 0.9m above the floor with a listening distance of approx 2.5m.

There’s a useful floor/ceiling reflection calculator here:

https://mehlau.net/audio/floorbounce/

 

[h.g.]

I don't get the histerical hatred toward ASR that I see sometimes on this forum.

Amir has excellent equipment, does industry standard measurements, has technical expertise to do it well and he isn't paid by equipment manufacturers.

Hatred looks a bit strong. Those with a strong audiophile faith are obviously going to dislike anything plausible that challenges their beliefs and so a degree of active opposition is to be expected. Particularly as opposition seems to be a part of binding/maintaining the faith.

What is perhaps less widely appreciated is that Amir has little scientific understanding, little interest in it and a low tolerance for those with this knowledge that express it an abrasive manner which is not uncommon. This has slowed the growth of good stuff on his site despite the large and sustained effort he has clearly been making. Nonetheless the site does seem to have improved a bit compared to a year or two back when I gave up on it.

The link in the OP clearly states that his speaker measurement hardware involved a "financial arrangement" which is only to expected these days. If he can avoid all the emotive language of audiophile reviews and stick to purely factual statements then it won't really matter how the equipment is obtained for measurement. Whether he is interested/capable remains to be seen but the more sites start to produce useful speaker measurements the more pressure will be put on (the better) speaker manufacturers to publish useful specifications for their products in the manner of companies like Neumann. More power to his elbow.