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March Audio Sointuva

ctrl

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Genelec etc can have better measurements coming from waveguided tweeter, but, if Sointuva was voiced well, it can actually sound better.
Agreed! Reasonably tuned, this can sound good (whether better as other speaker brands, I dare not predict). The drivers themselves are very good.

Except for a narrowing in the radiation in the range 800-2000Hz, the radiation can be very even.
The non-normalized sonogram could look something like this:
1630094092851.png 1630094114038.png
 

restorer-john

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March’s website says the crossover frequency is 1.5kHz.

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

1630104332455.png


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.

1630105893370.png
 
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Zvu

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As it is basically 6"+1" on flat baffle, crossover could be 2nd order midwoofer and 3rd order tweeter. That is standard solution, resulting quite often in wider directivity above crossover..

This is BliEsma T34B
 

Rick Sykora

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Will also be interesting to see how Sointuva compares to the Selah Purezza too. Assuming Selah stays in business, the Purezza is under $3000 in the US. I priced Sointuva to ship to me and it was over $4000. Admittedly March used better PRs, but the rest is probably a wash (if it reviews well).

Even if it reviewed well, would not be worth the price premium to me.:confused:
 

muad

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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
Isn't the 250w rating based on the entire speaker, including power required for the low end, which arguable account for the majority of the power usage? What SPL would 250 watts equate to? And what power is required for the tweeter to reach that spl in isolation?
 

restorer-john

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Isn't the 250w rating based on the entire speaker, including power required for the low end, which arguable account for the majority of the power usage? What SPL would 250 watts equate to? And what power is required for the tweeter to reach that spl in isolation?

Look, until the speaker is tested for long term power handling, according to the IEC spec he advertises, I'm going stay out of it, as he cannot defend himself.

If @hardisj is going to properly review this speaker at some stage, I would expect he would be confirming the 250W rating for at least the 28min IEC long term test (33% duty cycle) with shaped pink noise. I'm sure Alan will put up a replacement tweeter if it fails. ;)
 

Duke

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


I understand that it certainly looks that way at first glance, but in this case I think the claimed power handling is realistic, as far as the tweeter is concerned. This is assuming the same yardstick ("music program", "continuous", "IEC whatever", "AES whatever") is being used for the tweeter's wattage rating as for the system's wattage rating.

[EDIT: My assumption about the same yardstick being used for the tweeter as for the system was INCORRECT. I left the rest of the post up but with my initial assumption being incorrect, so is my conclusion.]

You see, there is a non-obvious factor which comes into play: The power distribution of music is nowhere near uniform across the spectrum. It goes down as we go up in frequency.

The ballpark rule of thumb I go by is that the wattage a speaker system can expect to see is equally divided at about 400 Hz, and is halved for every octave north of 400 Hz (it's more complicated south of 400 Hz. Anyway I've had less than 1% tweeter failures using this rule of thumb... but to be fair, I always err on the side of having at least some safety margin).

So if the crossover is at 400 Hz and the speaker is seeing 250 watts, roughly half of that will go north of 400 Hz and the other half south of 400 Hz.

The 1.5 kHz crossover of the Sointuva is approximately 2 octaves north of 400 Hz, so I'd expect the tweeter to see approximately 125/4 = 31.25 watts. (I'm using that 31.25 watt figure because it makes the math easy - as you will soon see, a few watts either way at this step won't matter.)

And now let's pad the tweeter down by 11 decibels, taking its 96 dB sensitivity down to 85 dB, and taking our 31.25 watts down to 2.5 watts.

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.

(It is theoretically possible for excursion to limit the power handling, but not in this case: The unusually large 3 mm peak-to-peak excursion of this 34mm diameter tweeter translates to almost 800 watts excursion-limited power handling at 1500 Hz.)

So I think March Audio is on safe ground with their claim... unless somebody hard-clips their amp.

[EDIT: 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.]

(It can be scary to trust the math this much. I make a bass guitar cab rated at 500 watts whose tweeter is rated at only 20 watts. Using 200 Hz instead of 400 Hz as the "equal power dividing line" for electric bass, the math predicted the tweeter would have enough power handling but with little safety margin. Over the past twelve years I've sold hundreds of these cabs and only had ONE tweeter fail.)
 
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Ultrasonic

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Having a nose at the product website I discovered two things not obvious from the discussion above. Firstly, the cabinet has two passive radiators on the rear. Looking for a picture to post here I then came across this other thread here on the subject, with more pictures and discussion:

https://www.audiosciencereview.com/forum/index.php?threads/march-audio-sointuva-speaker.17162/

The second thing on the website that I wasn't expecting was that apparenly the crossovers have an inductor that weighs 1.6 kg. I had no idea anything like that would ever be considered for a loudspeaker crossover!
 

Rick Sykora

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Am pretty pragmatic when it comes to speaker power ratings but if claimed (as March does) to a standard, it should meet or exceed the claim. As for much else…
  1. I suggest that few customers really give the speaker power rating much consideration as long as it seems reasonable.
  2. Unless you try to push this smallish speaker to pressurize a larger room, your likely to run encounter your threshold for pain before hitting the max power handling. Even if you do not…
  3. Few have any true ability to measure the exact power going into their speaker. So seems low risk that March or many other manufacturers are going to be challenged to prove their power rating. Most folks are more concerned that they have sufficient amplifier power and not whether the speaker can handle.
  4. Even if they could measure, even fewer fully understand what the power handling rating means.
So from a practical standpoint, the more factors that can be applied, the lower the probability anyone will challenge a given equipment spec is pretty low. Am pretty sure Alan understands the managed risk here in any case. :)
 
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Ultrasonic

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@Zvu Not sure if it's an issue my end but I see no text in your post above but when I clicked on reply to ask what the picture was of it showed you'd written saying it was the crossover going into the bottom of a Tidal Akira. Anyway, a rather larger loudspeaker but I take your point :).
 

Zvu

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@Ultrasonic It's me. I posted the pic and realized it kinda sucks not defining what i've posted :)

Since Purifi has rather low sensitivity the coil in series must be lowest possible Rdc and if you want to do it with air coil, you get to a 2kg coil pretty fast.
 

MZKM

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Will also be interesting to see how Sointuva compares to the Selah Purezza too. Assuming Selah stays in business, the Purezza is under $3000 in the US. I priced Sointuva to ship to me and it was over $4000. Admittedly March used better PRs, but the rest is probably a wash (if it reviews well).

Even if it reviewed well, would not be worth the price premium to me.:confused:
Is Selah not a one man operation? If so, I sadly don’t see how it could continue.
 

Rick Sykora

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@Ultrasonic It's me. I posted the pic and realized it kinda sucks not defining what i've posted :)

Since Purifi has rather low sensitivity the coil in series must be lowest possible Rdc and if you want to do it with air coil, you get to a 2kg coil pretty fast.

see if this helps a bit more…

The foil woofer coil in the Purifi SPK 5 is around a kilogram. Would not take too many other inductors to push the weight even higher. Weight would not be my metric of crossover performance, but am sure it explains some of the higher cost.:cool:
 

Rick Sykora

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Is Selah not a one man operation? If so, I sadly don’t see how it could continue.

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

dualazmak

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Zvu

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......The foil woofer coil in the Purifi SPK 5 is around a kilogram. Would not take too many other inductors to push the weight even higher. Weight would not be my metric of crossover performance, but am sure it explains some of the higher cost.:cool:

Weight is perfect metric in air coil performance if it's applied across the same class/range of products. If your foil coil in SPK5 is 2mH and weighs 1kg, use 2mH foil coil of larger weight made by same manufacturer and performance goes up :) (Rdc goes down).
 

Rick Sykora

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Weight is perfect metric in air coil performance if it's applied across the same class/range of products. If your foil coil in SPK5 is 2mH and weighs 1kg, use 2mH foil coil of larger weight made by same manufacturer and performance goes up :) (Rdc goes down).

Yes, but quickly gets to a point of diminishing returns too. May be a bit more attentive to weight as it is easy for some too forget that it adds to the shipping cost too.

However, I forgot to mention that a full blown amp with DSP weighs not much more and would have more benefits (granted with a bit more added cost as well). Imo, an active version would be really make it much more interesting in this price range.
 
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Mutsu

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This is one of the reasons I have refrained posting anything about my pair, which I've had since earlier this year. It displaced my Dynaudio C1s (which have been moved to rear surround duties.) Looking forward to third party measurements / reviews!

When I did a Google search for the Sointuva I think you were the only person that I saw (on another forum) mention that you have them.

I’d love to hear your opinion, if you’d prefer not to share publicly feel free to shoot me a PM. Thanks!
 
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