3 Way Tri Active design help

[SoundLogic]

Hello!

This is my first post
I am embarking on a new project ,trying to design a 3 way tri active (tri amped,active crossover) system.All ye audio gurus please give your valuable suggestions.

So here it is (per channel)

For the low section
2 x 12 inch Hertz DS300 (car audio I know) (in series ,each driver handles 150 watt and is 4ohm so 300 watt 8 ohm total)
170 litre Sealed (refrigerators ,I know!)

http://www.hertzaudiovideo.it/Doc/pdf_ds300.pdf

Mid/bass Xover 150-200 hz
1 x 8 inch B&C 8 PS21 or 1 x 8 inch Rcf L8s800 (170 watts nominal)
No idea how to load them (this is where I could use some help,I was thinking open backed box or something along the lines of a "boffle" )

B&C SPEAKERS

http://www.rcf.it/en_US/c/document_l...=DLFE-2195.pdf

Upper mid/treble 2.2-2.5 khz
1 x LCY 130 (ribbon tweeter)
These will be housed in their own individual 8 inch Dia turned wooded ,round enclosures.

LCY-130 Ribbon Tweeter 130 mm Round from Madisound

Amplification

Nad C355BEE doing duty as preamp for the whole setup and as power amp for the tweeters (power section can be isolated from the pre)

Crown XLS 602 (for the mids P.A.! I know,but they are cheap)

Crown XLS 802 (for the low)

Crossover

DBX 234XL



Whaddaya think? deal or no deal?

(Ps please ignore the thin cables in the pictures )

[DougL]

You will like tri-amping. You still need measuring capabilities to get the most from it, however.

Here are the issues as I see them.
One, the 8" woofer will start to beam around the proposed 2k+ crossover point.
This is not a bad thing if you are crossing over to a wave guide / compression driver.
If your tweeter is omnidirectional at that frequency. it is not the best for the power response.

HTH

Doug

[Loren42]

I would really ditch the two twelves and get something designed for HiFi.

Your choices are either a pair of twelves or I tend to lean toward a single 15". I would seriously consider the Acoustic Elegance TD15X.

The crossover frequency is too low. Change it to 400 to 500 Hz to get it out of the middle of the bass spectrum.

You need to determine if the polar responses for each driver match well with the next. This is hard because you really need to take your own on and off-axis responses of each driver (as well as taking your own Thiele-Small parameters).

The bass box should be designed around the woofers you select in the final design.

You may also want to consider the Behringer DCX2496. That's the Swiss army knife of active crossovers. It has a lot more versatility compared to the DBX unit for a similar price.

[doug20]

You may also want to consider the Behringer DCX2496. That's the Swiss army knife of active crossovers. It has a lot more versatility compared to the DBX unit for a similar price.

I agree, I have both and the DCX is superior in so many ways. There isnt much in terms of SQ difference between them either.

[SoundLogic]

Hi,
Thanks for your suggestion,I have considered changing those 12s,only problem is that nothing decent is available in my country save for professional drivers, importing AE's etc are going to be a whole new headache, the only reason why I went for these 12s are because they give a decent down to about 23hz and consume low power.The max I can push them to is about 200 hz on the top end.However there are a couple of brands that are available here are Fane,RCF,Eminence,B&C and I could try to source some Beymas but that might be a stretch.
Has anyone used any of the above brands? I cant seem to find a 15/18 incher that will get me much below 40hz that consumes about 400-700 watts (id like to reserve some power for headroom) ,im not taking into account in room gain/bass boost(should I?,if I do how low can I go? approximately?).

One of the reasons I am thinking of not using the DCX is that it adds another AD/DA conversion in my chain,although im not sure how good or bad these units sound ,but I feel that the non digital Xovers might offer better acoustic performance (less noise,more transparency,forgive me if I am wrong) albeit with much less flexibility,however I am not opposed to using a pro audio 30 band graph eq in the chain.
Anyone used Crown Power in home audio? are they good?

Thanks for your time guys,really appreciate the help.

[event horizon]

Hi SoundLogic

I wouldn't recommend you use those drivers in a 176L sealed coffin. The reason being is that you'll not be able to stick very much power into them bass wise before they run out of excursion

I modelled the thing earlier & wasn't very impressed tbh (I modelled a single driver in 88L.). Each driver (assuming the 92Db sensitivity is correct - though it might be 92Db/2.83V) will accept a maximum of approximately 33W before exceeding it's excursion limit. The low frequency rolloff will be 48Hz -3Db which is nothing to get excited about either

However, if you are prepared to get slightly more involved you'll be able to improve the possible performance of those drivers no end. I modelled the same driver (i only used one in each session) in a 60L reflex tuned to 30Hz. Now you'll get a bit of a peak in the response but with electronics this can be gotten rid of. What i did find was a much higher power input (as the port damps the driver & reduces excursion) & i managed to get a -3Db frequency below 30Hz.

All that in a smaller enclosure Now you might not like reflex enclosures, but what is little known is that if you stick a driver in a much smaller reflex enclosure than it's VAS it'll roll off very similar to a sealed box & as long as you correct for any peaks it'll have a similar transient response.

Up to you fella, i honestly wouldn't use them in a sealed box though

[Loren42]

Originally Posted by SoundLogic

Hi,
Thanks for your suggestion,I have considered changing those 12s,only problem is that nothing decent is available in my country save for professional drivers, importing AE's etc are going to be a whole new headache, the only reason why I went for these 12s are because they give a decent down to about 23hz and consume low power.The max I can push them to is about 200 hz on the top end.However there are a couple of brands that are available here are Fane,RCF,Eminence,B&C and I could try to source some Beymas but that might be a stretch.
Has anyone used any of the above brands? I cant seem to find a 15/18 incher that will get me much below 40hz that consumes about 400-700 watts (id like to reserve some power for headroom) ,im not taking into account in room gain/bass boost(should I?,if I do how low can I go? approximately?).

One of the reasons I am thinking of not using the DCX is that it adds another AD/DA conversion in my chain,although im not sure how good or bad these units sound ,but I feel that the non digital Xovers might offer better acoustic performance (less noise,more transparency,forgive me if I am wrong) albeit with much less flexibility,however I am not opposed to using a pro audio 30 band graph eq in the chain.
Anyone used Crown Power in home audio? are they good?

Thanks for your time guys,really appreciate the help.

I didn't see any frequency plots for those drivers, so I have no idea if or where the cone breaks up. You have to measure them.

You don't need drivers with ultra high power handling. That is a useless figure. It only tells you the voice coil will not vaporize at some posted limit, but has nothing to do with the amount of SPL that a driver can produce without distortion. That is the real story.

High efficiency drivers like 93 dB/W/m means you get 93 dB at one meter with one watt. So, extrapolating upward:
2W = 96 dB
4W = 99 dB
8W - 102 dB
16 W = 105 dB
32 W = 108 dB
64 W = 112 dB
128 W = 115 dB
256 W = 118 dB
512 W = 121 dB or hearing damage.

Additionally, you don't have those types of numbers on a continuous basis, it is where music peaks. There is much, much more to selecting a woofer than its Fs and power handling capacity.

Can you get B&C woofers like 15TBX100? This woofer has an SPL of 96 dB and will produce the above SPL with half the wattage that a 93 dB woofer can produce.

The benefits of the DCX2496 outweigh the disadvantage of digital.

[SoundLogic]

I can get my hands on the Beyma 12B100/R ,any suggestions?