Some Ambiguities, Zaph ZRT

[Creddy]

Greetings!

I’m not that good in the technical parts of building speakers (yet ;D), but not that bad in wood working.
I have been drooling over the Zaph revelator towers 2.5 (Zaph|Audio - ZRT - Revelator Tower) for a long time now, and I’m looking for someone that wants to clarify some things to get me closer to my dream. ^^,

First ambiguity:
Should I make these 2.5 way speakers with separate equal sized chambers for each woofer?
Aren’t the ZRT a bad construction by not being in that way?…
My point is that, when the .5 woofer are not “playing”, the other woofer is “playing” in a twice as big chamber that it is designed for?

Second ambiguity:
It is hard to get the correct values for the crossover parts in Europe.
How important is the values, how much can it differ?
Have I interpret the crossover properly ? (see attached pdf-file)


I think this is as close as i can get:



https://www.dropbox.com/s/h3fappgf3u...0Crossover.pdf
0.5 woofer is after the L14 coil, right?

Parts list:
http://i45.tinypic.com/dyxa1d.png


The parts i did find on Europe-audio.com
Original one:
http://zaphaudio.com/ZRT-2.5way-crossover.gif




Third ambiguity:
Do you like the looks of the custom enclosure? ;D
http://i46.tinypic.com/qppl68.jpg
a bit dark for some screens tho ;P


Best regards!

/Grateful Swede

[sreten]

Hi, Zaph|Audio, rgds, sreten.

[6L6]

Originally Posted by Creddy

First ambiguity:
Should I make these 2.5 way speakers with separate equal sized chambers for each woofer?
Aren’t the ZRT a bad construction by not being in that way?…
My point is that, when the .5 woofer are not “playing”, the other woofer is “playing” in a twice as big chamber that it is designed for?

If you emulate as closely as possible the origonal cabinet, the chamber is designed properly for the intended use of the second woofer.

If the second woofer was a different driver, would you doubt the different size of the enclosure?

Remember that the second woofer is playing a limited range compared to the other one, and is there to compensate and equalize for some physical dips in the frequency response caused by the enclosure itself. This is not an MTM design.

Second ambiguity:
It is hard to get the correct values for the crossover parts in Europe.
How important is the values, how much can it differ?

If you are really worried about it, just order the crossover parts from Madisound, they will have the exact pieces. That way you won't have to doubt that you have the 'proper' crossover...

However, If you can get as close as possible with the parts you can easily get, that will be fine also.

Third ambiguity:
Do you like the looks of the custom enclosure?

Yes, Very much!!

[dumptruck]

Originally Posted by Creddy

My point is that, when the .5 woofer are not “playing”, the other woofer is “playing” in a twice as big chamber that it is designed for?

That doesn't happen. See the individual responses (green and pink):

[oneplustwo]

I worry about the recess of the drivers. That might impact directivity and BSC in a negative way. Perhaps also phasing/coherency? Also, it would be ideal to have a 3/4" roundover on the front baffle although folks debate whether that is actually audible?

[dumptruck]

If it's the same recess on everything, the phase would be fine. Unnecessary chance of diffraction, though.

P.S. Are these to two you can't find?
- 15uF, you could add 1uF in parallel if you can't find 16
- 82uF instead of 80 is okay

[pski]

I built the Madisound kit (+ crossover upgrade.)

https://www.facebook.com/media/set/?...1248869&type=1

These are the 65L design found on the Zaph site made of full 1" MDF. (expanded by .5 inches to account for the difference in the 3/4" design. I made my braces to accommodate a #20 biscuit. This reduced the volume by about 1.5 liters.

I would not risk separate woofer enclosures. The speakers sound great as built. My only caution is that the "stuffing" shown in the design proved very excessive in my build. I counter sunk the woofers to the start of the chamfer and the tweeters to flush mounted. The 3/4" quarter-round was done on the inside of the baffles around the woofers (per Zaph's recommendation.) Also, if you build, note using the measures shown for the ports caused my braces to interfere so I had to cut the inner lip of the "horn" to get them to seat properly.

These speakers are very strong and will be best in a larger room with plenty of separation from the walls. (Everyone who has heard them asks where I've hidden the sub-woofer.)

The Adcom 2x100 GFA-545 is sufficient to run you out of the house but depending on the program material, you can make the amp go to speaker protection. I usually listen at a little less than have volume on the active GFP-565.

P

[Creddy]

Originally Posted by dumptruck

If it's the same recess on everything, the phase would be fine. Unnecessary chance of diffraction, though.

P.S. Are these to two you can't find?
- 15uF, you could add 1uF in parallel if you can't find 16
- 82uF instead of 80 is okay

Yeah those are the ones ; ) ofc, its only simple addition! bit tired.. ;D

About the recess, dont think it is much deeper then the Magico Q7,
so maybe the diffraction is ok ? is it possible to make that parable?


If the recess would make any difference it would make the soundwaves "spread" more, or what would be the audible difference?

[xjr100]

Originally Posted by Creddy

It is hard to get the correct values for the crossover parts in Europe.
How important is the values, how much can it differ?

R0, 2.2Ohm
Mundorf MOX MR10-2,2

C1, 16uF
Make it from Mundorf Supremes: 15+1
Sup8-15 and Sup8-1

L2, 0.25mH 0.15Ohm
You can use CFC16-0,27, it is 0.16Ohm - it will add about +0.3db in area at 1.5 to 2.5db, what I think is not bad

C4, 80uF
You can safely use 1 x 82uf MCap250
This capacitor is not very important, you can use electrolytics here to save the costs.

L5, 1mH 4.7Ohm
l100-1 0.49ohm
and 2 pcs in parallel MR5-8,2Ohm

L8, 0.5mH 0.22Ohm
l140-0,47 - 0.19Ohm - I think it will work
If not - take 0.56mH and unwind it to 0.5mH

C10, 30uF
MCap250-15 2pcs
C11, 60uF
MCap250-15, 4pcs

L14, 3mH, 0.185
H140-3 0.18Ohm
If you go for aircore coils you need something really big (and expensive!) like L250-3.0 0.24Ohm and 3kg
L140-3,0 0.55Ohm will give -0.3db in area upto 200Hz.
It will be almost onnoticable, but if it is used in combination with changes of L2 (+0.3dB in 1.5...2.5kHz)), than listening picture can be different.

So, all the project will be 363EUR = ~3100SEK with free shipping

[giralfino]

For the 80uF cap you can parallel 33 and 47 uF caps if you want the exact value, but I doubt that using a 82uF cap would make a difference (80-82 is a 2.5% difference). I wouldn't use a bipolar because they change over time.

For the L5 R6 couple I would use a 1mm wire 1mH coil (resistance about 0,4 Ohm) and add a 4R3 resistor (you can find one with the Superes).

For the 0,25 and 0,5 mH coils I would chose the more cheaper wire version, just keep the appropriate resistance (e.g. 1,2 or 1,4mm wire for the 0,5 mH coil).

For the 3mH coil just use a cored one (e.g. JANTZEN-5012).

For the enclosure I strongly suggest you use the same exactly baffle as the Zaph one - no recesses. On the tweeter it could (and probably will) change directivity.

Ralf