March Audio Sointuva

[Holmz]

Erin measured an older version of the Sointuva (meanwhile there are several versions of the LS). The sensitivity of the version Erin measured is 82.6dB (avg. 100Hz-1kHz for 2.83V measured at 1m) with an f3/f6 of 43.9/36.6Hz - see spinorama.org data section of the speaker.

Since the new version is tuned lower, its sensitivity is lower. According to the measurements published here in the thread rather at 81-82dB (avg. [email protected]@1m).
View attachment 307759
But it is perfectly normal that such a low-tuned LS with only one 6.5'' woofer has a low sensitivity - for this you don't need a subwoofer at low SPL.
If you don't have a need for very high sound pressure levels, then you get a SOTA speaker.

Only for the use as near field monitor one should wait until the vertical frequency response measurements are published, because to achieve the linear SP and PIR response in the range of the crossover frequency one has to use some kind of "constant power filter" (typical would be Butterworth 3rd order or not so typical a Linkwitz-Riley 4th order (LR4) allpass filter with shifted phase,...), which usually leads to somewhat wavier vertical frequency responses around the crossover frequency than with typical allpass filters like LR4.
In simple terms, the vertical frequency responses are "all over the place" in the crossover frequency range, but provide relatively linear vertical sound power on average.

@ctrl or @Rick Sykora

Sirs,
How would changing the XO to be first order affect things?
(Assuming I using something the Octo DAC8 to get the time <and phase> alignment.)

 

[Rick Sykora]

@ctrl or @Rick Sykora

Sirs,
How would changing the XO to be first order affect things?
(Assuming I using something the Octo DAC8 to get the time <and phase> alignment.)

I recall @ctrl has a thread that speaks to crossover orders elsewhere here, but do not recall if it talks much to 1st order slopes. Trying to keep OT in this thread, suppose you should ask Alan March. That said, there are a couple of considerations to keep the discussion focused:

1. What is your goal in specifying a first order network?
2. Can the goal be achieved with the Sointuva?

Once you answer #1, can discuss why Sointuva (and most comparable 2-way designs) would be (at best) questionable candidates to crossover using 1st order slopes.

 

[restorer-john]

I recall @ctrl has a thread that speaks to crossover orders elsewhere here, but do not recall if it talks much to 1st order slopes. trying to keep OT in this thread, suppose you should ask Alan March. That said, there are a couple of considerations to keep the discussion focused:

1. What is your goal in specifying a first order network?
2. Can the goal be achieved with the Sointuva?

Once you answer #1, can discuss why Sointuva (and most comparable 2-way designs) would be (at best) questionable candidates to crossover using 1st order slopes.

I would consider that Alan has busted his proverbial butt to produce a loudspeaker that can exhibit the performance it does. It really doesn't need "re-imagining", but some people just can't leave stuff alone.

With efficiencies as low as they appear to be, overall system performance can be maintained due to residual noise from attached amplification being mostly rendered unimportant, as long as there is enough power on tap. Perfectly valid approach IMO.

I'd really like to hear and experience his new version of the Sointuva. Pity he's, like, 4300km away (8600km round trip). LOL.

 

[Holmz]

I recall @ctrl has a thread that speaks to crossover orders elsewhere here, but do not recall if it talks much to 1st order slopes. Trying to keep OT in this thread, suppose you should ask Alan March.

Well - he is about 20km away, but…

That said, there are a couple of considerations to keep the discussion focused:

1. What is your goal in specifying a first order network?

I would like to use with existing HT speakers which are 1st order.
And despite Toole et. al. Saying that the phase does not matter, there is something attractive about the pressure waveform coming out of the speaker looking the same as what the microphone recorded. O flip it around Willy-nilly, seems to go against what makes sense.

1. Can the goal be achieved with the Sointuva?

Well I got a piece of Myrtle so have a set and an agreement with Alan, but then it went sideways.

Once you answer #1, can discuss why Sointuva (and most comparable 2-way designs) would be (at best) questionable candidates to crossover using 1st order slopes.

Thanks!

 

[Holmz]

I would consider that Alan has busted his proverbial butt to produce a loudspeaker that can exhibit the performance it does. It really doesn't need "re-imagining", but some people just can't leave stuff alone.

With efficiencies as low as they appear to be, overall system performance can be maintained due to residual noise from attached amplification being mostly rendered unimportant, as long as there is enough power on tap. Perfectly valid approach IMO.

I'd really like to hear and experience his new version of the Sointuva. Pity he's, like, 4300km away (8600km round trip). LOL.

View attachment 307958

It is a long way across the Nullabor. But they do have the worlds longest gold course, so that is attractive if one is a golfer.

 

[AudioJester]

I would consider that Alan has busted his proverbial butt to produce a loudspeaker that can exhibit the performance it does. It really doesn't need "re-imagining", but some people just can't leave stuff alone.

With efficiencies as low as they appear to be, overall system performance can be maintained due to residual noise from attached amplification being mostly rendered unimportant, as long as there is enough power on tap. Perfectly valid approach IMO.

I'd really like to hear and experience his new version of the Sointuva. Pity he's, like, 4300km away (8600km round trip). LOL.

View attachment 307958

Brisbane to Perth is an easy flight.
Go to the Melbourne hifi Show if you want closer. Actually not sure if he is presenting there?
His bigger speaker looked and sounded sensational at the Sydney show.

 

[Rick Sykora]

Well - he is about 20km away, but…


I would like to use with existing HT speakers which are 1st order.
And despite Toole et. al. Saying that the phase does not matter, there is something attractive about the pressure waveform coming out of the speaker looking the same as what the microphone recorded. O flip it around Willy-nilly, seems to go against what makes sense.


Well I got a piece of Myrtle so have a set and an agreement with Alan, but then it went sideways.



Thanks!

I am very sure Dr. Toole was not talking about the phase matching of 2 drivers in a loudspeaker. The phase of one loudspeaker relative to another at frequencies above the room modes is another matter…

What speaker are you trying to match and what does it claim to achieve with a first order crossover?

 

[Matias]

From Alan:

"I have recoded a quick video showing a pair playing whilst monitoring the SPL on a Bruel and Kjaer SLM.

Ignore the sound quality as it's just a mobile phone mic. It was uncomfortably loud to my ears! They will stay cleaner and go as loud as anything of a comparable size, in the region of 108dB pk"

 

[Sokel]

From Alan:

"I have recoded a quick video showing a pair playing whilst monitoring the SPL on a Bruel and Kjaer SLM.

Ignore the sound quality as it's just a mobile phone mic. It was uncomfortably loud to my ears! They will stay cleaner and go as loud as anything of a comparable size, in the region of 108dB pk"

108db (A) (or is C weighed,can't tell) peaks at 3 meters is respectable considering the size!

 

[Holmz]

I am very sure Dr. Toole was not talking about the phase matching of 2 drivers in a loudspeaker. The phase of one loudspeaker relative to another at frequencies above the room modes is another matter…

What speaker are you trying to match and what does it claim to achieve with a first order crossover?

Here is Erin’s step response measurement:

https://dl.dropboxusercontent.com/s/ffbrs9v80in1yfj/March%20Audio%20Sointuva%20Step%20Response.png?dl=0

But the

Are here is the step function response of a Vandersteen VCC5 (from ASR):

However these are not quite the same measurement.

I thought that the phase of the middle driver (In a 3-way) was flipped in in things LP4, or maybe it was the butterworth?

 

[Holmz]

From Alan:

"I have recoded a quick video showing a pair playing whilst monitoring the SPL on a Bruel and Kjaer SLM.

Ignore the sound quality as it's just a mobile phone mic. It was uncomfortably loud to my ears!

I would not say that my listening to them was uncomfortably loud.
It is odd when you hear a speaker and it sounds good, and then try to hold a conversation and realise that the things are way louder than one suspected.
I busted out the phone and it was 100+ dB(A)…

That almost never happens when the distortion is high, as they sound loud with high distortion.
And speakers generally do not sound loud when the distortion is low.

They will stay cleaner and go as loud as anything of a comparable size, in the region of 108dB pk"
…

They were certainly loud enough for anything sensible.
And they were in a typical sized room.

 

[Ra1zel]

From Alan:

"I have recoded a quick video showing a pair playing whilst monitoring the SPL on a Bruel and Kjaer SLM.

Ignore the sound quality as it's just a mobile phone mic. It was uncomfortably loud to my ears! They will stay cleaner and go as loud as anything of a comparable size, in the region of 108dB pk"

Nice way to show how to produce specific results that work for your favor, the speakers are positioned close to rear wall, one is in a corner, the room is completely untreated, in other words he is getting about ~6dB of room gain to help the speakers

I guess you can still get good levels with little room gain if you are fine with needing 500W of power

 

[JohnnyNG]

Wow! Would love to see the full measurement suite.

I'd imagine these would be a decent step up from my Revel M106, and that my Audiophonics 1ET400A mono amps would provide sufficient power. I'd high-pass to a sub.

 

[ctrl]

Ignore the sound quality as it's just a mobile phone mic. It was uncomfortably loud to my ears! They will stay cleaner and go as loud as anything of a comparable size, in the region of 108dB pk"

Nice way to show how to produce specific results that work for your favor, the speakers are positioned close to rear wall, one is in a corner, the room is completely untreated, in other words he is getting about ~6dB of room gain to help the speakers

Theoretically the room gain for the left LS in the corner is up to 18dB for the right LS up to 12dB.
For small to medium rooms with normal listening requirements, such LS are sufficient in any case.

But one should always say where the limits are and what can be problematic. If someone drives these speakers in a 50m² listening room with a large distance to reflective surfaces at a listening distance of 3m to 108-110dB, there is a risk of destroying the LS.

Assuming that in the low frequency range the signals are always coherent (which is not guaranteed), the sum of two LS provides 3-6dB more SPL (depending on the distance of the speaker to each other), the floor increases the SPL by another 5-6dB or so.
At a distance of 3m the sound pressure level is reduced by about 10dB.
So for very rough 108dB SPL at the listening position, each individual LS would have to deliver roughly at least 107dB SPL in the free field.

Thanks to VCAD, one can simulate the entire loudspeaker with both PR in the free field (4pi) in a few minutes and see, for example, what excursions would be necessary for only 100dB SPL.
At 26Hz the excursion would already be over 20mm (Xmax woofer is 10mm, mechanical max PR + woofer 15mm). Modern music plays up to 20Hz with full level.
So already at 100dB there is a risk that the LS is damaged using music with low frequency content.


Only if a protective high pass is set with DSP, for example second order high pass at 30Hz, the LS can safely deliver 100dB SPL without too much loss of low bass.


Possibly nothing will happen at 100dB yet, as the speaker already shows a significant amount of instantaneous compression below 50Hz at SPL above 96dB, perhaps limiting the excursion. But a loudspeaker doesn't have to fulfill superlatives in all areas.

 

[Matias]

For maximum SPL and low bass there are the towers, Ukkonen. Or high pass and add subs, of course. To me the Sointuva alone should be enough, let's see in October when mine should arrive.

 

[Rick Sykora]

Here is Erin’s step response measurement:

https://dl.dropboxusercontent.com/s/ffbrs9v80in1yfj/March%20Audio%20Sointuva%20Step%20Response.png?dl=0

But the

Are here is the step function response of a Vandersteen VCC5 (from ASR):

However these are not quite the same measurement.

I thought that the phase of the middle driver (In a 3-way) was flipped in in things LP4, or maybe it was the butterworth?

Without significant modeling, these drivers are barely overlap enough to support 1st order slopes. They would have to cross around 3 kHz (more than twice the current crossover point) and so would likely have a major impact to Sointuva’s directivity. Not worth it for just being able to claim minimum phase response in a narrow window...

Even if you found this acceptable, any automated room correction would add delays as it tries to compensate for differences in phase and amplitude response between speakers. Can discuss more offline if you feel a need for further elaboration but rather not offroad too much on this thread.

 

[Holmz]

For maximum SPL and low bass there are the towers, Ukkonen. Or high pass and add subs, of course. To me the Sointuva alone should be enough, let's see in October when mine should arrive.

When I heard them, they had a surprising amount to bass.
A sub would not hurt, however I doubt you will need one.
I would suggest that you should not have an expectation to use a sub, and see how you go when they arrive.

 

[Matias]

While I wait for my pair to be produced, not anxious at all as you can imagine, I found below 2 reviews of the drivers individually.

TL/DR: they are among the best in the market today.

SB Acoustics Satori TW29BNWG-4 beryllium tweeter in a waveguide

Satori TW29BNWG-4 | HiFiCompass

What is on the test bench? Another one novelty from Sinar Baja Electric has appeared in the Satori line - an unusual tweeter with a beryllium membrane TW29BNWG-4. Its singularity is that, as far as I know, at the moment it is the first and only beryllium tweeter in the world, which is a factory...

hificompass.com

Purifi PTT6.5X04-NAA-08 6.5" aluminum midwoofer

Purifi PTT6.5X04-NAA-08 6.5" Alu midwoofer | HiFiCompass

What is on the test bench? The Danish company PURIFI continues very confidently march to the Olympus of High-End speakers and seems has squeezed everything out of its line of 6.5" speakers with paper cones, bringing them to perfection. First, the company has produced PTT6.5X04-NFA -01...

hificompass.com

 

[witwald]

...they are among the best in the market today....

Purifi PTT6.5X04-NAA-08 6.5" aluminum midwoofer

Purifi PTT6.5X04-NAA-08 6.5" Alu midwoofer | HiFiCompass

What is on the test bench? The Danish company PURIFI continues very confidently march to the Olympus of High-End speakers and seems has squeezed everything out of its line of 6.5" speakers with paper cones, bringing them to perfection. First, the company has produced PTT6.5X04-NFA -01...

hificompass.com

The woofer, although quite good in its intrinsic frequency response performance levels, does seem to have some quite strong resonances in its upper frequency range. These are no less than 10dB peaks, located at about 5.2kHz and 9.8kHz. A lesser peak, of about 5dB or so is located a bit further up the frequency range. It would appear that the aluminum cone resonances could do with some additional taming through judicious application of a suitable damping treatment. That would easily elevate the performance of this driver even further.

In addition, the available frequency response curves seem to be quite smooth, but the data sheet doesn't include the amount of smoothing that was used (e.g., 1/6 octave, 1/12 octave, or 1/24 octave). It would have been nice to know this parameter, which can affect the published frequency response data.

 

[Rick Sykora]

The woofer, although quite good in its intrinsic frequency response performance levels, does seem to have some quite strong resonances in its upper frequency range. These are no less than 10dB peaks, located at about 5.2kHz and 9.8kHz. A lesser peak, of about 5dB or so is located a bit further up the frequency range. It would appear that the aluminum cone resonances could do with some additional taming through judicious application of a suitable damping treatment. That would easily elevate the performance of this driver even further.

In addition, the available frequency response curves seem to be quite smooth, but the data sheet doesn't include the amount of smoothing that was used (e.g., 1/6 octave, 1/12 octave, or 1/24 octave). It would have been nice to know this parameter, which can affect the published frequency response data.

Purifi acknowledged these resonances and offers remediation in the form of additional filtering. See here:

Low Distortion Filter for PTT6.5X04-NAA

purifi-audio.com

Their proposed fixes add significant cost to an already pricey driver, but at least Purifi is offering a solution.