March Audio Sointuva

[dualazmak]

Hello OP Mutsu and friends,

After the start of March Audio's thread on Sointuva in October 2020, I have been also much interested in the concept, design and development of the really unique Sointuva, and I have been waiting for hearing some review(s) by the end user(s) like yourself (and you are living in Japan!).

I understand that Sointuva has dual Purifi PTT6.5PR-NF1-01 passive low Fq radiators in rear panel of the closed box;

I assume, therefore, the positioning of Sointuva in our/your room, especially the distance from the rear wall and the material/nature of the wall, would be one of the critical factors in achieving the best performance in real home listening room acoustics.

I am also rather surprised that the target room Fq response shape of Sointuva looks very similar to my latest Fq response shape at listening position with my stereo 5-channel (5-way) multichannel multi-driver multi-amplifier system having rather large L&R sub-woofers YAMAHA YST-SW1000.
(The jump links properly edited/corrected)

I would highly appreciate if you could share your subjective impression on bass sound of Sointuva related to the rear wall of your listening room, and I am also very much looking forward to hearing about your possible future microphone measurement(s) at listening position.

Just for your reference, I use one measurement microphone BEHRINGER ECM8000 and an audio interface (having 48 V phantom to ECM8000) TASCAM US-1x2HR for room sound measurements with Adobe Audition 3.0.1 on Windows 10 PRO PC. as shared here, these well enable nice and reliable Fq response measurements over 20 Hz to 20 kHz.

 

[Mutsu]

The 'official' advertised long term rating of the speaker at 250W is clearly complete fantasy with a 1.5kHz tweeter X/over.

View attachment 149986

Here are the tweeter specs:

The rated power handling of the tweeter in accordance with IEC-268-5 cl 18.2 is a "system" rating of 80W (behind a 2.5kHz filter). March is crossing it even lower, so even with resistive padding burning up ~10dB in the crossover to match the sensitivity of the Purifi woofer, the tweeter is still in serious danger. But I'm sure he'll be quite happy replacing them under warranty as he'll be required to do under ACL.

View attachment 149988

Alan wanted to give me some piece of mind related to this, I copied part of his response that I think is most relevant below:

“The tweeter is far more sensitive than the woofer. It's input signal is reduced by around 12dB to bring its volume in line with the woofer. So let's run through the calculations. I will use some generic numbers for impedance, but it's close enough to demonstrate the point.

To run the woofer at its max 250 watts you would need to input about 32 volts. 32volts / 4 ohms = 8 amps.
8 amps x 32 volts = 256 watts

The tweeter voltage level is reduced by about 12dB. So 32 volts reduced by this amount equals only 8 volts. So 8 volts / 4 ohms = 2 amps. Therefore power is 2 amps × 8 volts = 16 watts. This clearly isn't any where near the 80 watt capability of the tweeter.”

I wanted to share this for anyone concerned.

 

[Mutsu]

Hello OP Mutsu and friends,

After the start of March Audio's thread on Sointuva in October 2020, I have been also much interested in the concept, design and development of the really unique Sointuva, and I have been waiting for hearing some review(s) by the end user(s) like yourself (and you are living in Japan!).

I understand that Sointuva has dual Purifi PTT6.5PR-NF1-01 passive low Fq radiators in rear panel of the closed box;
View attachment 150050

View attachment 150051

I assume, therefore, the positioning of Sointuva in our/your room, especially the distance from the rear wall and the material/nature of the wall, would be one of the critical factors in achieving the best performance in real home listening room acoustics.

I am also rather surprised that the target room Fq response shape of Sointuva looks very similar to my latest Fq response shape at listening position with my stereo 5-channel (5-way) multichannel multi-driver multi-amplifier system having rather large L&R sub-woofers YAMAHA YST-SW1000.

I would highly appreciate if you could share your subjective impression on bass sound of Sointuva related to the rear wall of your listening room, and I am also very much looking forward to hearing about your possible future microphone measurement(s) at listening position.

Just for your reference, I use one measurement microphone BEHRINGER ECM8000 and an audio interface (having 48 V phantom to ECM8000) TASCAM US-1x2HR for room sound measurements with Adobe Audition 3.0.1 on Windows 10 PRO PC. as shared here, these well enable nice and reliable Fq response measurements over 20 Hz to 20 kHz.

You’re also in Japan?

One of my speakers is in a far from ideal position. It’s very close to a side wall and also at a point where the wall turns in to floor to ceiling windows. However there are privacy curtains around the window area.

My rear wall is made of something called eco-carat. It’s a porous but hard material that is supposed to help manage and regulate humidity slightly (made to look like wood). I think the material has similar qualities to the (ceramic?) bath mats that absorb water when you step on them.

The speakers are about 45cm from the rear wall right now, this is the same distance Alan said his development pair were from the wall. I don’t have much space to play with here and moving a few cm forward or back didn’t really seem to change much. However increasing the distance the speakers were apart and changing the toe-in angle gave a noticeable change in soundstage. I didn’t perceive any fq change when doing this.

It’s a long time since I listened to other speakers than my Tannoy floorstanders, and I’ll caveat that I’ve not heard a huge range of speakers in the past. But the Sointuva’s are the best sounding speaker I’ve personally heard, and I think a lot of that comes down to the bass. It’s a big step up from my old speakers and while I don’t have fq data in my room yet, they seem to go down very low without boominess of my old speakers.

One thing I did notice was that if I stand near the left speaker, I can notice more bass, like it's trapped a bit in that corner. It’s not noticeable to me at my listening volume at my listening position. Bare in mind that my old speakers both did this at more frequencies.

I plan to measure and correct any room modes.

Hope this helps!

 

[dualazmak]

Hello Mutsu,

Thank you so much for your quick and in-depth response!

Yes, as you can find under my avatar, now I am in Ichihara City, Chiba Pref.

In late 2018, I returned from the USA (northern San Diego, La Jolla research triangle area) to Ichihara City where I and my wife have been keeping our house (and the audio/living room, of course) for more than 30 years. Although it is an afterwards-result-story, it was quite nice that I decided to semi-retire and returned to Japan in late 2018, otherwise we would not be able to come home because of the COVID-19 pandemic started late 2019 - early 2020, and it is also highly possible that I might have had my J1 visa renewal problems/difficulties ...

I know well about LIXIL's eco-carat since we recently rather intensively renovated our house, especially kitchen, dining room and bath area, toilets in 1st and 2nd floors, with all LIXIL materials and equipments! I believe eco-carat has nice acoustic tuning characteristics as you mentioned. Just for your reference, on our ceiling in the living/listening room, we have somewhat similar (to eco-carat) microporous diatom panels as shared/shown in my post here.

I just assume that rather thick and large carpet on your floor would effectively tune your room acoustics.

Just as another reference for you, REW's "Wavelet Analysis" (free software) would be much helpful to "see" your room acoustics, as I did it briefly as shared here to here.

Thank you again, and I am very much looking forward to hearing/viewing much more info exchange on March Audio's Sointuva here in your wonderful thread.

 

[Mutsu]

Hello Mutsu,

Thank you so much for your quick and in-depth response!

Yes, as you can find under my avatar, now I am in Ichihara City, Chiba Pref.

In late 2018, I returned from the USA (northern San Diego, La Jolla research triangle area) to Ichihara City where I and my wife have been keeping our house (and the audio/living room, of course) for more than 30 years. Although it is an afterwards-result-story, it was quite nice that I decided to semi-retire and returned to Japan in late 2018, otherwise we would not be able to come home because of the COVID-19 pandemic started late 2019 - early 2020, and it is also highly possible that I might have had my J1 visa renewal problems/difficulties ...

I know well about LIXIL's eco-carat since we recently rather intensively renovated our house, especially kitchen, dining room and bath area, toilets in 1st and 2nd floors, with all LIXIL materials and equipments! I believe eco-carat has nice acoustic tuning characteristics as you mentioned. Just for your reference, on our ceiling in the living/listening room, we have somewhat similar (to eco-carat) microporous diatom panels as shared/shown in my post here.

I just assume that rather thick and large carpet on your floor would effectively tune your room acoustics.

Just as another reference for you, REW's "Wavelet Analysis" (free software) would be much helpful to "see" your room acoustics, as I did it briefly as shared here to here.

Thank you again, and I am very much looking forward to hearing/viewing much more info exchange on March Audio's Sointuva here in your wonderful thread.

Thank you for the kind words.

That is one very detailed and interesting thread of yours. I’ll have to take some time to properly read through as I only scanned it for now.

That must have been a fairly pricey remodelling. I was surprised about the prices of the panels, but they do add some character to the room too. We chose a slate/stone looking one for one of our bedrooms walls.

I have a fairly thick rug/carpet directly infront of the listening position, and will probably be using REW for measurements with a minidsp umik-1. I’ve done measurements before using REW but it was for my old speakers and an uncalibrated mic.

I was fairly recently on a camping trip near Kisarazu, I think that’s fairly close to you. I’m pretty much across the bridge in Chuo-ku, Tokyo. My sister in law is also based in San Diego.

 

[Mutsu]

Just as another reference for you, REW's "Wavelet Analysis" (free software) would be much helpful to "see" your room acoustics, as I did it briefly as shared here to here.

Apologies, I just re-read this and noticed you were referring to something different. I’ll also check out your linked thread - again, interesting stuff and thanks for sharing!

 

[Kachda]

I recall his son was involved in Selah too, but to what degree and whether he wants to do, am not sure.

What happened to Selah audio?

edit: Nvm, just saw the post. Very sad indeed.

 

[Rick Sykora]

What happened to Selah audio?

Rick Craig passed last weekend.

 

[dualazmak]

Apologies, I just re-read this and noticed you were referring to something different. I’ll also check out your linked thread - again, interesting stuff and thanks for sharing!

You are quite welcome...

Just for example, my post here is sharing REW Wavelet images of room acoustics, such as delays, standing waves, reflections, resonances, measured at my listening position.

Yes, I had quite a long journey and intensive exploration in my multichannel multi-driver multi-way multi-amplifier project.

Only if you would have your relaxed occasion, and only if you would have some interests on multichannel multi-way stereo audio system where each of the speaker drives is driven by individual dedicated amplifier, you would pleased carefully read through my long blog-style thread...

 

[restorer-john]

The tweeter is rated at 80 watts thermal with a 2.5 kHz 2nd order filter, and we'd expect that to be halved (40 watts) one octave lower. If we only "need" 2.5 watts power handling for the tweeter, then the 40 watts we can reasonably expect translates to a 12 decibel(!) safety margin above the claimed 250 watts system power handling.

The tweeter is not rated at "80 watts thermal" with a 2.5kHz 2nd order. That is the system power, when used with a 2.5kHz 2nd order. And that rating is the 28minute "long term". The tweeter may see just a few watts of that after padding down. But at a genuine 250W, there's >5-10W (even after padding down) to get rid of and you and I know a tweeter of that construction will be unlikely to survive that. We are talking a CCA VC of 1.4mm in two layers and 4R. Not a lot of thermal mass in copper wire to absorb and disipate indirectly to the magnet structure.

As a company like Scanspeak specifically articulates in their data on power handling:

And this:

Just as the Purifi woofer has a 100hr rating (IEC) of just 80watts. The 250W is a 28minute IEC (33% duty cycle test).

Anyway, unless someone actually tests these speakers in accordance with the IEC spec advertised, nobody will know. That is, until they vaporize a tweeter on an otherwise benign transient or dynamic passage.

Typically tweeters on TOTL tweeters (think berrylium, titanium, diamond, alumina etc) had ratings of ~10W. Having dismantled literally many hundreds of tweeters over the years, 10W is pushing it. The VC wire can be thinner than a human hair. Or the flat, edge wound wire can only be seen under a microscope.

Here's a TOTL JVC Laboratory Series Diamond tweeter voice coil which has an enormous 1.5kg magnet structure. It is flat edge wound 6R and rated at 10W. Even 10W is pushing it as the lead in wire is 0.2mm total diameter litz copper- before it terminates to this single layer coil of only 1.6mm in total windings height.

 

[Duke]

The tweeter is not rated at "80 watts thermal" with a 2.5kHz 2nd order. That is the system power, when used with a 2.5kHz 2nd order....

Thank you for the correction, John! I have edited my post and retracted my conclusion because my initial assumptions were incorrect.

The 11 dB of padding required to get down to 85 dB should increase the system power handling proportionally, which would in turn be reduced maybe 3 dB or so by the lower crossover frequency. So 250 watts system power handling still seems reasonable to me, but without the huge amount of headroom implied by my mistaken initial assumptions.

 

[bigjacko]

@restorer-john I have seen people saying the tweeter power handling is very bad, just a few watts can destroy it, seems to align with what you said.

 

[restorer-john]

@restorer-john I have seen people saying the tweeter power handling is very bad, just a few watts can destroy it, seems to align with what you said.

Tweeters are only required to dissipate a small amount of power in real terms. The spectrum of typical music means there is little energy in the upper frequencies. That said, the lower in frequency, you cross the tweeter, the more power it "sees". That is the problem.

These particular speakers are unusual in that they are being crossed to the tweeter extremely low in frequency, and are being rated at a stupendous 250W long term. All we can hope for, is the excess power is being burnt up in the padding resistance prior to the tweeter. Otherwise, the rating is fantasy.

Again, as I said previously, unless they are tested, in accordance with their rated and advertised specifications, it's just conjecture, and completely unconfirmed as a specification. I tagged @hardisj hoping he would commit to testing for power handling, but it seems he is unable or unwilling to do so. Rather disappointing, especially from someone puporting to be extensively testing loudspeakers.

Power handling is more important than just about any other parameter in real terms, and yet these "reviewers" gloss over it and fail to test for it at all. Sad.

 

[q3cpma]

I tagged @hardisj hoping he would commit to testing for power handling, but it seems he is unable or unwilling to do so. Rather disappointing, especially from someone puporting to be extensively testing loudspeakers.

Power handling is more important than just about any other parameter in real terms, and yet these "reviewers" gloss over it and fail to test for it at all. Sad.

View attachment 150226

Eh? Do you buy him a new tweeter if it fails catastrophically? For active speakers with limiters, I can understand, but for passive speakers, the manufacturer can always say "you pushed it too hard", as there's rarely a proof it broke without doing so.

 

[Mutsu]

I apologise to seem strict, but can we please keep this factual unless you have real world measurements. I’m all for the search of truth, it’s part of my work in real life, but there are too many things being thrown out here as ‘bs’ without any proof.

I made this post in good faith and feel like it’s taking a turn

 

[dualazmak]

@restorer-johnn

I fully agree with you. I have never tried to, and will never try to, test my treasure Be-midrange squawkers, Be-tweeters and metal horn super-tweeters up to, or near to, the maximum spec power level since such challenges have very high possibilities of destroying these drivers. I believe the same for all of the SPs including March Audio's Sointuva.

And, even in my multichannel multi-way system where these drivers are directly driven by dedicated amplifiers, I always have low-cut (high-pass) protection capacitors for them, as recently posted here. I very carefully compared the Fq responses in SP level signal "before and after" the protection capacitors as shared here, and I fully confirmed that these protection capacitors are almost completely transparent for their actual operating Fq range.

I also configure Low-pass (high-cut) -48 dB/Oct crossover filters at 25 kHz for them in order to cut-off the (sometimes harmful) ultra-high Fq (ca. over 30 kHz) noises which very often included in improperly processed HiRes music tracks, as recently discussed here, and as I shared the actual high-cut configurations from here to here.

 

[dualazmak]

And, now.... Let's go back to info exchange on "Sointuva" itself!

 

[Phorize]

Maybe someone will get a Puri Bliss to Erin too. Would be interesting comparison to the Sointuva.

Has anyone made a puri bliss? I checked hifi compasses website and can’t see the design details have been released. For me the PB is a speaker I’m very interested in.

 

[Rick Sykora]

Has anyone made a puri bliss? I checked hifi compasses website and can’t see the design details have been released. For me the PB is a speaker I’m very interested in.

Me too, but the site admin must have bigger problems to address as (despite trying) never seem to be able to get a registration to go through.

There is more info posted on the waveguide version, but seems to be concealing design details as part of IP protection.

 

[Juhazi]

Remember to click " I'm not a robot"

Wg version looks best to me https://hificompass.com/en/projects/2-way-systems/puri-bliss-bewg