DIY 2-way with complete spinorama / CTA2034A measurements - Purifi and Scan-Speak

[tktran303]

 

[Vineeth Kumar V]

@tktran303: I like the white one on the top the most..
Wishing a belated merry Christmas too..

 

[Dmitri]

Really great stuff tktran…truthfully out of my league and knowledge base on the audio front, but I love the process…and the
build(s).
BTW…Kudos to you on your charity/plan share strategy. Your heart‘s in the right place. ; )

 

[tktran303]

Hey Dmitri,

Interestingly the post popular vote here at ASR is the aluminium cone with active crossover.

And that’s completed!

Over at DIY Audio the most popular vote is fibre cone with passive crossover.

This is very curious to me…

 

[Ra1zel]

Hey Dmitri,

Interestingly the post popular vote here at ASR is the aluminium cone with active crossover.

And that’s completed!

Over at DIY Audio the most popular vote is fibre cone with passive crossover.

This is very curious to me…

Tradition vs progress

 

[ooheadsoo]

Tradition vs progress

diyaudio is a very technically minded forum filled with competent engineers. Top contributors over there have been on the bleeding edge of audio for decades. Not sure what you're trying to say here.

If I had to guess, it would be because over there, they are more cost conscious and maybe know that they want to build more speakers later. Maybe it's easier to cycle through passive speakers than active.

 

[Citizen]

The goldiLocks sized speaker:
400 x 200 x 300mm

View attachment 240048
View attachment 240049

I think I am in love.

 

[tktran303]

@Citizen

Do you mind editing that post and removing the large video. It has it's own thread already:

Interesting new studio speaker design from present day production

A new studio speaker design from present day productions using hypex and bliesmas drivers, will be unaffordable and unnecessary for my listening at home but I’m interested in what the finished build will be like.

www.audiosciencereview.com

Measurements are why I'm here:

 

[Ra1zel]

@Citizen

Do you mind editing that post and removing the large video. It has it's own thread already:

Interesting new studio speaker design from present day production

A new studio speaker design from present day productions using hypex and bliesmas drivers, will be unaffordable and unnecessary for my listening at home but I’m interested in what the finished build will be like.

www.audiosciencereview.com

Measurements are why I'm here:

Pretty decent, just needs subs below 100hz

 

[tktran303]

I'm still gathering more data to clarify when users will most benefit from a subwoofer. In a small room eg. 10’ x 10’ x 8’ perhaps not for moderate listening levels.

At present for the P4
27cm x 13 cm x 17cm
10 1/16” x 5 1/6” x 6 11/16”
(H x W x D);
Internal volume: 3.3L

Tonality score: 5.5 (passive, No EQ, no sub)
Bass extension: 52Hz. (-6dB)

 

[Adi777]

@tktran303 You build also active speakers?

 

[tktran303]

Yes.

The XS active and Ma active and passive versions completed.
S and Mp (fibre cone) to come.
L version in planning stages...

 

[tktran303]

Here’s measurements of the Micro

 

[bigjacko]

Here’s measurements of the Micro

View attachment 334694

View attachment 334695

Nice directivity! What is the tweeter and why the directivity dip around 6kHz? Maybe baffle diffraction just above tweeter?

 

[tktran303]

@bigjacko

The tweeter is the SB19ST-C000-4

Yes you are right- the dip is diffraction related; the clue is that there is an on-axis dip, but it doesn't exist in the off axis.

As you probably know, if I were to correct for it, and completely flatten the on axis, then I'd get peaking in that 5-7 KHz area:

ie.:

5-7KHz is not really an area where one needs excess energy bouncing off walls...

 

[tktran303]

I keep getting private messages about my reference system. Unfortunately the drivers are now difficult to source worldwide, since they are over 10 years old and difficult to purchase in single units.

Apart from the jagged dip at 5KHz due to diffraction of the baffle with the tweeter, I'm quite pleased with the on-axis response.

Here's the VituixCAD2 6-pack, including the CTA2034A and "preference" rating.

But there's more to speakers than preference rating.
You see, small speakers (specifically small woofers) will have difficulty with dynamic range. A small speaker can have a good preference rating of 5-6, but doesn't mean it is capable as a much larger speaker with the same preference score.

eg. Genelec 8030C and 8050B both have same preference rating of 6.2. But one costs $700 and the other costs $1900. What gives?
Well it's in the dynamic range. The ability to play louder, more cleanly.

Here's the 8030C:

Not bad, you say.

Well here's the 8050B:

Wow! Even better.

What about the even bigger 8361A - that has a preference score of "only 7.0". But it costs US$5000 each. What gives?
It can knock out 106dB, albeit with some tweeter limitations:

Amazing. And I expect nothing less.

But I'm aiming for life-like (live) levels, so I took some distortion testing at higher THX Dominus-type levels.
It's hard to do this accurately because it needs a very quiet environment. I waited until everybody was away, in the dead of night.
Now I know that "quiet living room at night" is ~35dB. The black line marks -50dB, similar to the practice at ASR.

I didn't do the whole 120dB @1m THX Dominus thing. Maybe next year, when the family are away for the holidays...