Adire Speaker Idea .. comments?

[kfr01]

Heya .. new to the diy speaker building. I am very interested in Adire's technology and have been impressed with their car audio products. Now I am interested in building a high quality home speaker system. I want full-range reference speakers. Hopefully I can figure out how to implement a digital 4-way stereo crossover system on my PC, because I don't want to mess with passive crossovers (is this a mistake?)

Anyway, what do you think of this configuration? Any comments? Driver details here: http://www.adireaudio.com/

2 Extremis 6 drivers and a Vifa XT ring radiator tweeter in a sealed MTM configuration at the top of the tower.
1 Koda 8 Midbass driver below.. sealed.
1 Shiva 12" sub driver below that .. sealed.

I hope to crossover like this:
Shiva .. up to 60hz
Koda 8 .. 60-200hz
Extremis 6 Drivers .. 200-2khz
Vifa Tweeter .. 2khz+

I am thinking about using a Rotal 40x8 @ 8 ohm amplifier which puts out 65x4 @ 4ohms .. which is what the impedence of these drivers is. I will probably buy a separate plate amp for the Shiva.

Please comment! This all sounds awesome in my head, but I'm a newb.

[Luke (Uof Iowa)]

If you're using the Extremis and the Shiva, I don't think you need to have the Koda8, since the Extremis should be able to play down to a reasonable level for the Shiva. Also the XT tweeters that I know of will not play to 2K as well as many other tweeters would.

I'm also confused about the electronics end. You have an 8 channel Rotel amp? I wouln't advise using your computer as a source for reference level. If you wanted to go active then maybe using a CD player and a pro crossover unit like something from Behringer would work. I don't know if there's many cheap 3-4 way crossovers. But then you would also have to have seperate inputs for each channel on the Rotel amp.

If you wait long enough, I'm sure there will be passive two-way designs using the Extremis and some tweeter.

[4real]

Originally posted by kfr01
... new to the diy speaker building...digital 4-way stereo crossover...(is this a mistake?)

Well, to be honest, I don't thinkt you should make 4-way system if you are new to DIY speaker building, and specially not with the combination of those units. Any idea of how big this monster would get?

No offence, but I would recommend doing something simple first to get some feeling for speaker DIY'ing, before plunging into such a massive project (don't underestimate a digital crossover, it is not simpler that a passive one!). Maybe a 2-way with the extremis as said above.

[morbo]

I agree with both the above posters, no need for the Koda, and a 4way is extremely complex for a first system.

[kfr01]

Thanks for the comments guys. I think I might try doing without the Koda 8. Why is the computer a bad source for reference level?

By digital crossover I meant a software + soundcard based solution. There has to be something like this out there.

One of you asked which amp I plan on using ... it is: http://www.rotel.com/products/specs/rmb1048.htm 8 channel amplifier.

[Timn8ter]

Originally posted by morbo
I agree with both the above posters, no need for the Koda, and a 4way is extremely complex for a first system.

Extremely complex, period

[Grahamt]

If you wait long enough, I'm sure there will be passive two-way designs using the Extremis and some tweeter.

Get in line behind me. I'm hoping someone comes up with a MT design when the Extremis 6 ships out. Adire will have something but I dont know when or how much the tweets will cost. Dont blame me for not trying though, I did my best with my limited knowledge.

Kfr,

If I did my maths right, you could build a 2-way with the Extremis and then build a Tumult for about the same money (not including any amps).

BTW, the BL curve for the Extremis is up now. Very flat of course.

[kfr01]

Telling me something is extremely complex doesn't really help. I have the wood working skills. I plan on skipping the passive crossover learning curve and step. Since I'm going sealed I don't think the volume will be out of control - especially if I remove the Koda 8 from the setup. Any other _real_ reasons why this won't work? I mean, thanks for warning me about the complexity .. but it would be better to give me -reasons- as to why it will be so complex or why I should not try it.

Also, one of you commented that 2khz is too low for the vifa ring radiator. http://www.d-s-t.com/vifa/data/xt25tg30-04d.htm

500hz is the resonant frequency and vifa lists 1.5-40khz as the usable frequency range. Won't 2khz by fine at 24db xo slope?

[4real]

Originally posted by kfr01
Any other _real_ reasons why this won't work? I mean, thanks for warning me about the complexity .. but it would be better to give me -reasons- as to why it will be so complex or why I should not try it.

Also, one of you commented that 2khz is too low for the vifa ring radiator. http://www.d-s-t.com/vifa/data/xt25tg30-04d.htm

500hz is the resonant frequency and vifa lists 1.5-40khz as the usable frequency range. Won't 2khz by fine at 24db xo slope?

Okay, if you really want this... Then I think I should give you reasons why you should things differently (or not)

- first of all, I would not use the extermis in a MTM design. The woofer (even if they are great) are much to big, with means you have to cross way to low (probably under 2 Khz). I would recommend two smaller 4" or 5" woofers. You can use a higher X-over frequency and the smaller woofer have a better off axis response.
- Lose the Koda, but you already knew that
- I guess the X25 will handle the 2 Khz, but you should look at the distortion at those freuqencies, too!
- Don't use amps with the same power ratings for the various uints! The tweeter will not need nearly as much power as the shiva will. I would recommend to give the shiva lots of power (300W or so), and the tweater (and mid units), a little less (I guess 100W would be more than enough).

So, a MTM with 4" or 5" woofer, with a shiva (maybe on the side), will give you a better result, and if you use a Linkwitz transform, it doesn't need to be that big.

Sill: don't underestimate the digital X-over!

I plan on skipping the passive crossover learning curve and step

You cannot skip this learing curve, since with a digital X-over, you still have the same concepts! You still have to measure the units and simulate and try the filters. The only difference is that you don't have analog components to play with. You have a some kind of software to make the filters. It might seem less work, but I don't think it will be! I hope you will use a hardware digital X-over, and not your soundcard...(note that they are expensive)

Building a X-over is actualy the most difficult part of making a speaker. If it is bad, your speaker will be bad! I recommend sending a lot of time on research on this topic. Spend lots of time with tweaking the X-over! Fortunatly with a digital X-over, you can do that without the need to spend extra money

Good luck

[morbo]

Well you can read 'extremely complex' as 'you won't likely get a good result unless you are an expert at crossover design'. There are many talented speaker designers out there who don't even attempt a 3 way until they have 5 years expeience under their belts. In short - it would be a great learning exercise, but the odds that you would get the kind of 'reference system' you expect are fairly low, at least early on. Active or passive, a 4 way system is extremly complex to design. However, with enough time and experience, I expect you could get a nice result. It just won't be a 'run a few simulations, then plug and play' type process. If you decide to go ahead , you might look at something like this:

http://www.behringer.com/DCX2496/index.cfm?lang=ENG

controlled by some easy to use software like LSPCad. This would at least allow you to hear changes in your crossover in realtime, shortening your experimentation/tweaking process greatly.