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March Audio Sointuva Speaker

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LearningToSmile

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Very nice aesthetic, I personally like the "rough" look of the purifi woofers.

Out of curiosity, what is the cabinet material? Standard MDF/HDF or something fancier?
 

waynel

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This has been teased for a while now, we decided to put it on hold at the start of covid but are now ready for release.

The Sointuva (Finnish for musical harmony) is based on the Purifi Ptt6.5W04 woofer, PTT6.5 PR passive radiators and the Bliesma T34B-4 Beryllium tweeter. Im not going to go into a lot of detail in this post but just wanted to show some pictures and of course a measurement.

How does it sound? Well its exceptionally low distortion and clean. Equally it is a warm sound with very deep bass extension, particularly for its size. The high frequencies are sweet, extended, fantastically detailed and not a hint of harshness.

Prototype pics

View attachment 90468

View attachment 90469

View attachment 90470

Semi free field measurement. Ignore below 100Hz, its not accurate. More measurement will be coming later.

On axis and listening window.

View attachment 90471
I’m surprised to see no waveguide. Can you talk about your thoughts on that?
 

MZKM

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I’m surprised to see no waveguide. Can you talk about your thoughts on that?
While waiting on his response, my speculation is thus:

1) Waveguides on tweeters are to shape the off-axis response and increase the lower-end sensitivity to allow a lower crossover point.
2) This tweeter’s measurements show it already has a great off-axis and can easily cross at the chosen 1500Hz. So, no need.

This thus avoids a con of waveguides, which is reduced dispersion at those lower treble frequencies towards the rear of the speaker, reducing the size of the soundstage.
 

q3cpma

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While waiting on his response, my speculation is thus:

1) Waveguides on tweeters are to shape the off-axis response and increase the lower-end sensitivity to allow a lower crossover point.
2) This tweeter’s measurements show it already has a great off-axis and can easily cross at the chosen 1500Hz. So, no need.

This thus avoids a con of waveguides, which is reduced dispersion at those lower treble frequencies towards the rear of the speaker, reducing the size of the soundstage.
The real point of waveguides is to match driver directivity at the crossover point. Fortunately, by using such a low crossover frequency and big tweeter, the problem is almost non existent; see these HiFiCompass off-axis FR:
t34b-4_315mm_offaxis_0.png

ptt6.5w04-01a_offaxis.png


I'm also quite skeptical about the claim that all waveguides inherently narrow the HF response (claim that you didn't make, but that I often hear, same myth as "true ribbons are always wider").
 
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ctrl

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1) Waveguides on tweeters are to shape the off-axis response and increase the lower-end sensitivity to allow a lower crossover point.
2) This tweeter’s measurements show it already has a great off-axis and can easily cross at the chosen 1500Hz. So, no need.

The tweeter measures itself fantastically on an infinite baffle, but since it has no directivity control whatsoever (the dome half-shell of the tweeter is level with the baffle), the edge diffraction of the cabinet has a very strong effects.

In a German speaking forum I helped a little bit with some simulations to develop a 2-way loudspeaker with a 34mm Bliesma tweeter - it wasn't easy and ended up with a very flat waveguide to better control the directivity of the tweeter, although the project should explicitly do without WG.

The horizontal directivity of the sointuva-speaker should be anything but optimal, which of course doesn't mean that the speaker can't sound very good with good crossover tuning.

If you like you can use this link to browse a little bit through the pictures of the simulations, in most cases they should be self-explanatory (even without knowledge of German).
 

q3cpma

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The tweeter measures itself fantastically on an infinite baffle, but since it has no directivity control whatsoever (the dome half-shell of the tweeter is level with the baffle), the edge diffraction of the cabinet has a very strong effects.

In a German speaking forum I helped a little bit with some simulations to develop a 2-way loudspeaker with a 34mm Bliesma tweeter - it wasn't easy and ended up with a very flat waveguide to better control the directivity of the tweeter, although the project should explicitly do without WG.

The horizontal directivity of the sointuva-speaker should be anything but optimal, which of course doesn't mean that the speaker can't sound very good with good crossover tuning.

If you like you can use this link to browse a little bit through the pictures of the simulations, in most cases they should be self-explanatory (even without knowledge of German).
Interesting, didn't know the effect of diffraction could be that radical.
 

gr-e

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Interesting, didn't know the effect of diffraction could be that radical.
You can actually see some diffraction between 2500-3500Hz in the posted measurement (where the listening window is louder than the on-axis response)
 

q3cpma

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This has been teased for a while now, we decided to put it on hold at the start of covid but are now ready for release.

The Sointuva (Finnish for musical harmony) is based on the Purifi Ptt6.5W04 woofer, PTT6.5 PR passive radiators and the Bliesma T34B-4 Beryllium tweeter. Im not going to go into a lot of detail in this post but just wanted to show some pictures and of course a measurement.

How does it sound? Well its exceptionally low distortion and clean. Equally it is a warm sound with very deep bass extension, particularly for its size. The high frequencies are sweet, extended, fantastically detailed and not a hint of harshness.

Prototype pics

View attachment 90468

View attachment 90469

View attachment 90470

Semi free field measurement. Ignore below 100Hz, its not accurate. More measurement will be coming later.

On axis and listening window.

View attachment 90471
Really like the cabinet, but I feel these were a design inspiration:
000167379_5.jpg
 

MZKM

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The real point of waveguides is to match driver directivity at the crossover point.
avoids a con of waveguides, which is reduced dispersion at those lower treble frequencies
A con can also be a pro :)

But, you ideally would crossover before the woofer starts to beam, so both should have very wide dispersion at the crossover point.

The modest roundover is helping keeping diffraction minimal. A more extreme physical method would be to have a curved baffle. My Wharfedale Jade towers have a curved baffle and rounded side walls (which meet together, so no rear panel), sadly the baffle edges aren’t really rounded, not sure why they didn’t add a roundover.
 
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Chromatischism

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While waiting on his response, my speculation is thus:

1) Waveguides on tweeters are to shape the off-axis response and increase the lower-end sensitivity to allow a lower crossover point.
2) This tweeter’s measurements show it already has a great off-axis and can easily cross at the chosen 1500Hz. So, no need.

This thus avoids a con of waveguides, which is reduced dispersion at those lower treble frequencies towards the rear of the speaker, reducing the size of the soundstage.
I've never heard that, but I for one don't want my tweeter firing backwards at the front wall so I would consider that a benefit.

But even if you can match the crossover really well, the problem with large tweeter + no waveguide is you will have narrowing directivity at higher frequencies, reducing the size of the "sweet spot", the field in which the sound doesn't change and has a similar spectral mix. It's all about what tradeoffs you're willing to make.
 

VeerK

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Very attractive, I remember you teasing this a while back. What are the dimensions?
 
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March Audio

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Really like the cabinet, but I feel these were a design inspiration:
000167379_5.jpg
Like ;)

It will be available in any colour you like. They will be made to order As the cabinets are made by local craftsmen we can also accommodate specific finishes (wood instead of painted) by arrangement.
 

Emlin

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Like ;)

It will be available in any colour you like. They will be made to order As the cabinets are made by local craftsmen we can also accommodate specific finishes (wood instead of painted) by arrangement.

That's a bit sexist, surely.
 
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March Audio

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That's a bit sexist, surely.
Not at all. I knew someone was going to pick me up on that :) but no worries.

My view is that I dont like political correctness. The people that make the cabinets for us are men. Its a simple statement of fact without any assumed or implied gender discrimination. I just dont feel the need, and I dont think we should generally, keep having to point out "Im not sexist" wherever it has potential be misconstrued as such.

Just for interest my wife is a civil engineer. Designed and built roads and bridges. She has worked in the nuclear industry, mining industry etc. Male dominated industries and has dealt with and managed some misogynistic attitudes towards her, so I would seriously be a dead man if I exhibited any such tendencies ;) . However even she has a sort of "FFS" attitude however to "unnecessary"political correctness.
 
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March Audio

March Audio

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I've never heard that, but I for one don't want my tweeter firing backwards at the front wall so I would consider that a benefit.

But even if you can match the crossover really well, the problem with large tweeter + no waveguide is you will have narrowing directivity at higher frequencies, reducing the size of the "sweet spot", the field in which the sound doesn't change and has a similar spectral mix. It's all about what tradeoffs you're willing to make.

It is indeed about the tradeoffs and compromises. All speaker designs are compromises and hopefully the designer can manage to decide on the least negatively impactful choices.

As an example we started with the T34A tweeter. It actually is better off axis than the T34B above about 10kHz. However in the listening test that were conducted most preferrred the T34B. As mentioned earlier we managed a better crossover integration with the B.
 

AudioJester

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Alan, so how low will this design go? What is the F3?
 

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March Audio

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Alan, so how low will this design go? What is the F3?
I would like to do some further testing before committing to that number, but from early box size modelling and measurements it should be in the region of 50Hz and F6 at 40Hz.
 
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