Erin's review for the March Audio Sointuva

[hardisj]

@hardisj why in your reviews there is no in-room response published any more?

Time.

I used to do that in every review at first but after I proved to myself that the PIR indeed matched (which I discussed in this video) then I got more lax. I still do from time to time. But I have to disconnect all the Klippel stuff from my laptop so I can bring it from the garage into my home in order to get the measurements. And every time I disconnect the NFS from my laptop I have to run through the calibration steps again which doesn't take too long but is just one more step to add and I don't see the point in doing it every test.

 

[hardisj]

Lots of talk surrounding the HF. I think some of it is due in part to the measurement rig differences and from what has been posted elsewhere, it seems Alan's intent was to make the response (more) flat than what I measured. But, I'd also expect there to be some intentional lift to combat the narrow(er) radiation pattern.

But, rather than continue to postulate, I have emailed Alan to ask and I'll let you all know what he says.

 

[hardisj]

His wife has kicked him out of the loungeroom. It has to be an 'in-garage' response now.

 

[hardisj]

It's tempting to tilt on-axis up to get more linear PIR (and SP) to get better rating on ASR,

Please, see post #131. (also quoted below)

Spoiler: HF tilt

:
Alan and I went back and forth on this a bit. His measurements weren't showing as much of a lift as mine. I think we were about 2dB apart. You can look back in the Sointuva thread where someone posted his data and see his measurements don't show this lift. I verified my measurements with a different mic. Alan did some digging on his end and tracked down the reason(s) for the difference. Based on his findings and mine, he said he is going to update his measurement rig and also tweak the HF. He also noted a couple other things he is considering to perfect the design based on the measurement differences. I've pasted his reply about those potential tweaks below in the spoiler. And I told him I'd be willing to re-test. This is the same as I have done with other manufacturers/designers when unintended differences were discovered between measurement systems (DIYSG HTM-12 and Neumi BS5P, for example).

Spoiler
I'm building the new test rig tomorrow to improve the microphone alignment. I think with the other corrections that will bring my measurements very close to yours at HF.

As mentioned previously I will tweak the tweeter XO to bring the HF down. Also I have made another value tweak to one of the inductors on the woofer XO which will flatten further the slight hump centred around 700Hz. It will also change to an air core as the reduced value makes it smaller and possible to fit it on the board. This may provide a small reduction in distortion at very high signal levels.

One other change I'm considering is to very slightly increase the box volume. This will flatten out the slight bass hump at 150Hz and provide slightly more LF extension.

If you are up for it I will send a production unit with these final mods through in a month or so.

 

[Holmz]

... I'll test those because I think it is worthwhile for the community.


- Erin

Well I appreciate your efforts.

Most speaker manufacturers, do not provide measurements, or sometimes their data is off by a few dB say in sensitivity.Z

I do not usually do Patreon, but I believe that this service is a huge value to the community… so I even bumped up the Patreon a notch.
(Like your work M8.)

 

[hardisj]

Well I appreciate your efforts.

Most speaker manufacturers, do not provide measurements, or sometimes their data is off by a few dB say in sensitivity.Z

I do not usually do Patreon, but I believe that this service is a huge value to the community… so I even bumped up the Patreon a notch.
(Like your work M8.)

Dude, you've always been a positive person and I appreciate that.

 

[hardisj]

Oh, as for unit-to-unit consistency which we all understand is a problem even for well established manufacturers (see: Vance Dickason's reviews in Voice Coil Magazine* for proof of raw driver consistency). I did do a gated measurement comparison of the two units once I got the new crossovers installed. Mainly to make sure I didn't screw anything up.

As you see below, the two match quite well. At the point of greatest deviation (~1218Hz), the difference is only 0.628dB. The rest is about ±0.20dB. That could even be down to *exact, perfect* aiming. I'm honestly shocked at how close that is. Especially when you consider that I didn't use $100 audiophile solder.

* Side note: If you don't subscribe to VC Mag, you're really missing out.

 

[sigbergaudio]

@Matias I think your quote failed a bit up there. Anyway, both Amir and Erin has said yes to test them actually, but I'm considering to have them measured with a Klippel locally first. This community is pretty ruthless if anything is amiss..

 

[abdo123]

@Matias I think your quote failed a bit up there. Anyway, both Amir and Erin has said yes to test them actually, but I'm considering to have them measured with a Klippel locally first. This community is pretty ruthless if anything is amiss..

ground plane measurements are just as accurate, perhaps with lower resolution.

 

[sigbergaudio]

ground plane measurements are just as accurate, perhaps with lower resolution.

Better safe than sorry

 

[hardisj]

But, rather than continue to postulate, I have emailed Alan to ask and I'll let you all know what he says.

UPDATE: Alan said he's seen the thread and replied with the following and gave me permission to share in full:


Hi Erin

Regarding my response to the forum about the crossover, HF lift and other issues, I would say the following:


"Erin suspected a problem with one of the speakers and sent some data through. After examination it looked like a crossover issue and Erin confirmed my suspicion that an inductor had come loose and disconnected. Note these are prototypes and not representative of the final build where components are cable tied for security. My bad, they obviously should have been.

I asked Erin if there was someone local to him I could employ to swap out the crossovers if I sent replacements through, however Erin very kindly said he would do the change. I am very grateful for his time spent doing this. There was certainly no "significant exchange" between us regarding tuning the design of the speakers as has been suggested.

What Erin's final test data revealed was that whilst it is very consistent with our own, there was a difference above about 7kHz with Erin's data showing 1 to 2dB higher amplitudes.

So, as some members have suggested, the design intent was to keep a smooth sound power and PIR. Our data indicated a small HF lift, but this certainly remained well within the +3dB limit band. None of our subjective test subjects found this to be excessively bright.

So working on the basis that Erin's data is absolutely accurate and there was something wrong with our testing regime until proven otherwise, I have been thoroughly examining test set up, calibrations and methods. Now let's be clear, *ALL* measurement systems have tolerances and accuracies, including the Klippel. No one should expect two disparate systems to produce absolutely identical results. The examination of our system has revealed a couple of reasons (one was very interesting in fact ) for about a 1 dB difference. We will be performing some further measurements tomorrow and I am expecting this to come very close to Erin's data, although I still suspect a fraction lower.

Assuming this is the case we will make an additional crossover tweak to bring that HF lift down. The sound power and PIR will remain almost perfectly linear even with this adjustment. It should also bring the early reflections a tad lower and more linear at HF.

Regarding wide verses narrower dispersion, there is no right or wrong answer here. You will find Floyd Toole is quite clear about this. FWIW my view is this: wider dispersion will give a wider but more diffuse sound stage. Instrument placement will be more vague than with narrower dispersion. Narrower dispersion will provide a more precisely placed sound stage but it can be perceived as narrower. You may prefer one over the other.

Wider dispersion will interact more with the room. It can often sound a bit brighter as a result, but this does depend on the nature of the reflective surfaces and their distance from the speakers. Narrower dispersion as a result tends to provide a more consistent sound between different rooms.

Again there is no right or wrong answer here, but the major "Toole" principles apply; trying to ensure smooth on and off axis response and smooth directivity.

Regarding the flatness of the sub 100Hz response, it should be borne in mind that LF level is going to be impacted and raised by boundary reinforcement and users can tune the level by changing proximity to the rear wall. Basic stuff most people know. However Erin's subjective and a few numbers comments on this has prompted me to look again at the tuning and it may be actually a simple adjustment to improve this without sacrificing extension. Tests tomorrow will confirm the idea."


There you go.

 

[hardisj]

^ and with that, I'm done replying here for the day. I've got other speakers to measure/review and a kid to take care of.

Peace.

 

[buz]

My guy, you literally just said I had a conflict of interest and said I needed to disclose (something) when I already had discussed this in 2 threads here, on my YT page and on my FB group page.

Well, I read the post on your website.

As far as conflict of interests go, clearly I have a different view of them as I did not mean that as some sort of attack but merely as a matter of fact. I deal with them in my work to know they cannot always be avoided but should be acknowledged openly.

FWIW, I don't really have a horse in this race - I bought 4 R3 (on your and amir's review) and a R2C (largely on your review) just before Xmas. Reminds me I should donate to you, too

 

[Rick Sykora]

Thanks Erin!

Alan's experiences are very comparable to what we encountered with Directiva and we were using Amir's Klippel as a design tool. Even more notably, I see even more similarities as we try to finalize a solid passive crossover for r1...

For this reason and others, I remain skeptical about looking too microscopically at speaker measurements. Even if the tilt stays, there are compensations and March's customers will be the final arbiter. Along with the previously stated potential differences, variabilities in the human condition ((physiologically and psychoacoustically) leave the door wide open for people to have different sonic experiences. Am not saying we should not target good engineering practice, but should also acknowledge the limitations of working with electromechanical transducers to reproduce sound. Perfecting is great goal, perfection remains a much more elusive beast!

While the offering is a bit pricey, if I needed a medium monitor, would certainly consider the Sointuva. As the Purezza is NLA, the next closest speaker is the Salk BePure2 and they are much larger and more money. Happy hunting!

 

[Chromatischism]

Indeed. When I posted in-room measurements of my Klipsch RP-280Fs, they were criticized for being "very bright", etc. I sometimes wonder if the reaction would have been different if I hadn't mentioned the brand.

View attachment 177412

That is very bright indeed. The speaker in the OP would show a downward slope in-room.

 

[sweetchaos]

Update from Erin:

As explained in the video...Alan will be sending the speaker for re-measurements, coming in a month or two.

 

[Newman]

I don't agree with your (@witwald) assessment that an on-axis response that varies from flat is necessarilly a problem.

Toole’s research led him to conclude that it is, indeed, necessarily a problem. It is a primary goal for perceptual preference, and should not be sacrificed in order to solve overall room sound problems. In fact, that is the primary reason why speakers with flat on-axis plus well-behaved off-axis became the most-preferred.

 

[BenB]

Toole’s research led him to conclude that it is, indeed, necessarily a problem. It is a primary goal for perceptual preference, and should not be sacrificed in order to solve overall room sound problems. In fact, that is the primary reason why speakers with flat on-axis plus well-behaved off-axis became the most-preferred.

With all due respect, you are misrepresenting Toole's conclusions. Toole and Olive are rather open about the fact that their preference equations due not necessarilly hold for speakers with atypical dispersion patterns. They simply didn't have enough time and resources to test sufficient numbers of disparate types of speakers.

 

[holbob]

Oh, OK. That's unfortunate.

I figured we had a genuine, warts and all, honest review here, not a bounce back and forth, get-it-right before publication thing.

It's a rare post that makes me wish for a unlike emotion. It's a pity March Audio can't post here. Surely he's served his sentence. He's not novac dickarich is he??

 

[witwald]

Toole and Olive are rather open about the fact that their preference equations due not necessarily hold for speakers with atypical dispersion patterns.

Toole (1986) wrote:

• "Listeners, it seems, like the sound of loudspeakers with a flat, smooth wide band on-axis amplitude response that is maintained
  at substantial angles off axis. If this is achieved, the loudspeakers will exhibit smooth (but not flat) sound power responses and directivity indices."
• "The on-axis response is very important, though not only for the obvious reason that it describes the first sound arrival at the listener's ears. In loudspeakers of domestic size, with low directivity indices, the axial response also conveys much of the basic pattern that is revealed in all other measurements of amplitude response."

The issue here may be that having an "atypical dispersion pattern" is not necessarily, in and of itself, of any particular benefit to the listener. It may just be adding to Olive's "circle of confusion", rather than reducing it.