12" OS zvukovody

[MaBat]

BTW, this is my last measurement of the raw WG (DE250), 5ms window, no additional smoothing (Holm can't do gated smoothing. Xover now can, but I'm lazy):




(blue = Abbey's, red = mine, ~30deg)

12LW1400, cca 4ms window (need more free space, maybe at our local gym soon):


12LW1400, nearfield, 1/9oct:


I was a bit surprised by the amount of woofer's energy up to 4-5kHz. 12TBX100 falls like a stone above 1kHz or so, which is probably a good thing. Anyway, my aim is 24dB/oct crossover so that is quickly inaudible.


Woofer and "tweeter" sensitivity comparsion (with plug installed, which is about -2dB):



Impedances:


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Eminence DL-II 2512 (I had a bit more time then and a turntable working):

[jzagaja]

Our aim is 24dB/oct passive or active? I did several calibrated impedance measurements with line and head out and there's no important difference. Also in my room levels are ok. Lowering parallel resistor will lead to low impedance at HF. Below is level difference revisited.

[MaBat]

I will use miniDSP, so 24db/oct digital, along with all the necessary equalization and delay - that's the idea. Only if I didn't want to connect CD directly to an amplifier output, I would add some passive components (capacitor + compensation).

I listened to miniDSP today and I'm satisfied with the sound. Nothing to complain about.

[jzagaja]

Do you have miniAMP too? I realized only one Mummy is louder. Crossover seems alright.

[MaBat]

Some inconsistency with STX drivers?

- No, only DSP+digi.

[jzagaja]

Drivers are consistent. Below with 4,7uF.

[MaBat]

12TBX100:



What was the problem then, Jack? Do you know yet?

[MethMan]

MaBate to je opravdu dobrý měření. WG je učebnicový. I 18sound vypadá velice dobře. 12TBX má těžší membránu a asi líp tlumený okraj závěsu. Nemyslím, že by to měl být problém.

jzagaja - what are the woofers? Seems broken or very bad to me. Drivers are also not so good.

[MaBat]

12TBX je každopádně špičková volba. Zvlášť do pasivní výhybky. Opět ale jenom předpokládám, že tohle je samotnej reprák bez výhybky (což je, nebo aspoň dřív byl v reálu 2.řád, L a RC). Ukazuju to totiž tak, jak jsem to dostal, a to bylo bez podrobnějšího popisu...

[jzagaja]

MethMan - why do you think they are bad?

http://www.stx.pl/gdn-30-400-8-se.html
http://www.stx.pl/d-800-8-ti.html

[MethMan]

Circa 10dB deviation in driver's passband or means it's bad or broken. How can you get 6dB difference between L/R? Mess in the crossover? I don't buy manufacturer specs unless otherwise proven, sorry.

[jzagaja]

After careful examination of the crossover I've found first capacitor unconnected (it is FR4 laminate). That was a reason of unbalanced sound. This week we have AES symposium and I will give it to lab room on loan:

http://www.ntiav2010.zut.edu.pl/

[jzagaja]

First run-up with miniDSP/DIGI/AMP/STREAMER. Very positive - in BTL mode miniAMP is able to drive 15" woofer with 10dB boost at 50Hz. Zero noise and soft start. Power supply Speedlink 120W universal notebook power adapter set to 22V.

[jzagaja]

Pictures from Audioshow 2010.

[MaBat]

So? Any impressions?

Those are subs on the first picture? Maybe I'd like it black better.

[jzagaja]

4th order bandpass sub (12"). Deep bass but too much power required. Have feeling TL is better - more tight and only 10W needed. As always room is a key. White is our standard color. Stone, popart is now possible. "Rockets" - large horn setup is smoother than Mummies thanks to BMS ringradiator and Monacor KU-516 midrange. You can play insanely loud without aggressive sound. We had guys who travel for 5 years to different shows with "Sepultura" CD and told me both are the only one that can cope with heavy metal. They were compared to Avantgarde, MBL101 and Steinway-Lyngdorf. Next year when we take gallery room like MBL we will play live concerts. Please note "Rockets" were adjusted with miniDSP very roughly by using ear. Interestingly room was much crowded when we was playing RAP music or metal. Next stop High End Praha 2010. Rockets will be taken by Voxativ. BTW: their horn loaded fullranges are really good.

[MaBat]

High End Praha 2011? We shall meet there. Looking forward to hear all of those.
I guess Mummies could be improved by better transducers. With subs, you definitely need volume for sensitive low end, that's for sure.

I only hope I'll be ready for audition of my finished pair in spring, when you are in Praha

- BTW have you made any changes to Mummies's crossover since your post 104? What is in #104 still looks a bit "shouty" to me...

[jzagaja]

No crossover change since #104. Better sold as is and start new project with BMS4538 (old was a bit smaller than 1").

[jzagaja]

A family of elliptical OS waveguides.

[MaBat]

Hi Jack,

What are the dimensions? To not loose directivity control down to crossover frequency, it'd need to be as tall as a round 12" WG, I'm afraid. Otherwise it will be much wider in vertical beam than the woofer around the crossover. This all makes it pretty big.

Well, I'm curious about the result - you probably gain something by smaller center-center distance (if you make it vertically smaller) and maybe get rid of the axial hole but overall I'd be a little afraid of the crossover region...

Anyway, we probably could (or should) have made our 12" WG eliptical a bit. Next time