New project: Bliesma T34B in WG, 18WE, 32W

[PKAudio]

DSP was Octo Research DAC8 with implemented minidsp SHARC. I got this HW from the client and we planned active project around it.

I did not try bass boost, natural response proved to be enough during listening tests.

 

[jumper981]

Hi @Pida, late at the party that are impressive results!
Could I ask you how you removed the grill from the tweeter?
is the waveguide aperture exactly 34mm?

Many thanks in advance.

 

[eltomassito]

On htguide forum user Ergo posted info about removing the grille from T34B. Google for "htguide a 2.5way with SB midwoofers and a Bliesma tweeter" post number 10

 

[jumper981]

Many Thanks @eltomassito.

Now need to know the exact throat dimension of the waveguide; for the moment i choose 40mm as from measurements posted here seems 39.6mm.
Simulating with ABEC seems to perform good.

 

[augerpro]

I wasn't able to get ABEC results that matched my measurements for the T34B. The dome really needs to be close to spherical to use ABEC, and the T34B is not. T25B modeled well in ABEC.

 

[jumper981]

Thanks Augerpro for your answer

Did you modeled the tweeter source when simulating?
I use ATH4 and done my best to simulate it, but more probably something wrong.
I should try to contact Bliesma for exact measurements but I doubt that will release it.

 

[augerpro]

Yes i used the tweeter source. Exact measurements won't matter, the dome is not spherical, and ABEC only models spherical and flat sources. Unless there has been a change recently.

 

[jumper981]

I don't know if I explained correctly that was the dome source I used, not the standard flat or spherical cap.

Maybe I am pointing the same thing.

 

[augerpro]

The dome is a portion of a sphere, correct?

EDIT: now I see what you mean, ATH has an idealized sphere source. That's not what I meant. I mean the dome source, but just pointing out the shape of the dome must be spherical.

 

[jumper981]

I actually think that i tried to distort it a bit and was not properly spherical.

Posted the config of ath 4.7.0.

 

[PKAudio]

My WG has aperture diameter 39.6mm but this requires careful centering. It is better to make it 40mm, it will not make the measurements worse, profile itself is more important.

 

[jumper981]

My WG has aperture diameter 39.6mm but this requires careful centering. It is better to make it 40mm, it will not make the measurements worse, profile itself is more important.

Many thanks @Pida
I supposed to do so and done 40mm too.
Do you have some sketches of the diagram?
As me and @augerpro were pointing that simulations seems a bit unpractical.

Many Thanks in advance.

 

[PKAudio]

I do not have the dome profile. I actually did not make any sims for this WG, it is OSWG with the right diameter, angle etc kind of lucky guess. It showed to work well with scan speak domes and ring radiators, and later to fit also T34B and providing good measurements.

 

[jumper981]

@Pida did you tried both the 25B and the 34B?
if yes, which one you preferred?

Thanks

 

[fluid]

The dome is a portion of a sphere, correct?

EDIT: now I see what you mean, ATH has an idealized sphere source. That's not what I meant. I mean the dome source, but just pointing out the shape of the dome must be spherical.

Ath uses sections of arc's in the source contours file, ABEC itself can simulate whatever mesh can be created in another way. If the mesh created isn't close to reality then the simulation has no hope of being accurate.
@jumper981 the Bliesma has an inverted surround, one of the things that make it work well on a waveguide.

 

[PKAudio]

@Pida did you tried both the 25B and the 34B?
if yes, which one you preferred?

Thanks

Yes, I used both in Waveguides, and T25B also without wg.
Both are excellent and sound basically same, though T34B in WG was even more special. It is hard to describe it ... Part of the magic could also be in the midrange, 18WE.

 

[SSassen]

Quick question, did anyone try the Jantzen waveguide on the T34B? It is meant for the Seas T35C002 or the Audax TW034 tweeters which are in the same dimensional category.

 

[PKAudio]

T34B+JantzenWG could work reasonably well. Surround outer diameter is 40mm, Jantzen WG has 44mm.
I know that JantzenWG works well with TW29TXN, and with BN it will measure also fine as both versions has very flat dome profile.

If T34B availability issue persists, I will try to replace it with TW29BN+JantzenWG.
I would like to build 32W/4878T11 ported+18M+TW29BN+JantzenWG a lot.

 

[SSassen]

I've always found the T35C002 to be a very nice tweeter and by adding the Jantzen waveguide it can be crossed much lower, perhaps that's another option you may want to evaluate? Also, did you ever start selling waveguides for the T34B?

 

[PKAudio]

You are another one recommending T35 tweeter, I will think about it for my next projects.

I did not start selling T35B waveguides itself. To me it seems easier for onyone to have it printed locally without additional shipment cost and repacking on my side. I can offer STL of the waveguide if anyone asks via email, for 5-10eur. I like beer and good wine .