3 way design help with bi amp bass section

djwhog

Member
2008-02-17 8:29 pm
I have owned these Dynaudio drivers new in the boxes for a few years now.

Bottom line I am looking at a Eton 12" driver or am open to buying another well matched 12" driver or use 2 24W100 per cabinet that I laso have for the bass section.

I need a crossover design for the 3 way section, and a design for the bass driver too dependant on the driver for the bass chosen. The bass will be a single board bi-amped and the top end section will be a 3 way design.

Ok here is what I have and want to build.

Cabinet is:

A Tower 15”x15”x47” internal size ( it can will be sub-divided for the 7" woofer and a lower 12" driver too)

I have these Dynaudio drivers listed below and would need to purchase a good matched bass 12” driver for the lower end. I was going to do a 4 way design, but I think a 3 way is better matched and make the bass not a sub woofer but rather a bi-amped section so that overall I have a more defined faster bass section that a typical sub woofer.

Have Dynaudio drivers all rated 8 ohms and power handling D21af 600 watt range, D54 in the 600 watt range, and 17w75 150, 24W100 180 and all have Transient power rating near 1000 watts. These drivers all have large voice coils.

I know from other 2 way designs I have with a D28af and same 17w75 for one pair I own, and I also have a 15w75 D28af set, that they are very sweet sounding and do require a fair amount of power which I am OK with.

On the 3 way section here are the drivers I have. I would also like the Midrange to be a little more laid back and not to forward. I prefer a slightly more open clean louder top end.

My take is like sitting in a concert, I don’t want to be in rows 1-15, I prefer the mid range more subdued like being maybe 60% back from the sound stage.

I decided to add the D54 however since I think it will help make the vocals a little more clearly present than just using the D21af which is brighter than a D28af and in combination with the 17w75. I think using 3 drivers instead of two would allow each driver to be crossed over in a range that would not being stretching the driver as much. I think the added mid range helps in cutting off the D21af somewhere in the 2500-5000hz range bottom, the D54 in the 1000-1200 on the lower end and somewhere in the 3500-4500 top end, the 17w75 in the bottom 50-2000hz top ranges


I think too that adding the lower bass end that maybe the 17w75 should roll off maybe near 60-80hz to allow better power handling and let the 12” woofer take over from 150hz and down.

I would like to use this driver an Eton 12" HEXACONE Woofer 12-680/62 Hex for the lower end bass and can run it bi-amped in a separate internal divided section within this tower. Or could I use 2 24W100 per cabinet to get the job done?

These are specs from the Dynaudio sheets with their recommendations as a bass line listings. I have more specs from all the sheets if needed?


D21af ¾” dome tweeter
QMS=.82
QES=1.21
QT=.41
FS=1300 Hz
SPL=89db
Recommended frequency response 1500-45000


D54 2” done mid
QMS=1.00
QES=0.56
QT=0.36
FS=350 Hz
SPL=89db
Recommended frequency response 800-7000


17w75 7” mid woofer
QM=2.8
QES=1.1
QT=0.8
FS=40 Hz
SPL=89db
Recommended frequency response 40-3000

Possible bass Section options

Eton 12-680/62hex 12" woofer
QM= 2.87
QES= .33
QT= .29
FS=23 Hz
SPL=91db
Recommended frequency response 25-500


24W100 10" woofer(2)
QM= 1.54
QES= .35
QT= .28
FS=25 Hz
SPL=91db ??
Recommended frequency response 25-3000

I need some help on the crossover design for these drivers. I recall Dynaudio most times only needs a simple 6 db crossover. But if something better needs to be done to match with the smoothness better and the bass driver that is fine. I would like the design with the best parts within reason. I will be driving the top end with a 300 watt per ch McIntosh Amp, the lower end bi-amped with a 350 watt per channel Parasound amp.


Thanks for the help! :)
 
What you need is something similar to the DYNAUDIO Compound 4.
Dynaudio - Authentic Fidelity
I think this has double drivers:
Compound-system: a 2-chamber enclosure in which an inner driver creates the effect of an infinite air space behind the external bass driver

Here some information on the DYNAUDIO Compound 5 xover, not for your case.
Tuning einer DYNAUDIO Compound 5: Teil 1

Without checking, you should be fine with something like this Visatons, for your idea, unless you want to press for 1order.
Visaton - Lautsprecher und Zubehör, Loudspeakers and Accessories
If I was you, I would take this as a good/serious starting point for the final speakers and start enjoying them very fast. Of course, overall, they need to be adjusted, but that would be small details, like frequency curves/output, SPL level/attenuation (resistor Lpads)...
http://www.visaton.com/bilder/weichen/gross/casablanca_iii_w.gif
Now djwhog, study this last (Visaton) speaker I give you well, and you end up with a good idea of your final speaker system.;)
 

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thanks will look at this too.

What would you do for just the crossover network for the 3 dynaudio drivers?
What do you mean... Is that your first question (post #1)?

As another starting point, you can start by using two (4 for the pair) variable L-pads on the xovers for the mids and tweeters, in conjunction with the "final" xover and instead of the (L-pads) resistors. And measure them in a later time, for final values of the resistors, as we do here in diyAudio.
http://www.parts-express.com/wizard...AT&srchCat=196&CFID=12012162&CFTOKEN=49046834
 
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