Advice for FAST with alpair 7

Veggiel · 18th June 2011, 09:44 AM

I want to build a FAST system using the Alpair 7 and Minidsp, the design would be quite similar to the B&W 802 diamond.
In the thread of the Blanda speakers Ikea spherical speakers, first build done. there where some interesting ideas of how to make the droplet like B&W does.

Now my question is would it be possible to use the 20cm Blanda bowls or do I have to use the 28cm ones? I will most likely cross them at 300hz.
So I was thinking that the smaller size bowls should still be ok if the don't have to go that low.

For the bass drivers I was thinking of using two CSS TRIO8 drivers per speaker, would these be good drivers for this purpose or are there better alternatives?

DYNABLASTERTUNERS · 18th June 2011, 09:56 AM

Instructions on making a spherical enclosure(it's german but you will get the idea)

YouTube - ‪WERKANLEITUNG BETONKUGEL‬&rlm;

Veggiel · 19th June 2011, 04:38 PM

That's an interesting way of building a bowl, but I think I will stick to the Blanda bowls for now.

So the question is can I go to Ikea and get a couple of 20cm Blanda bowls to use with the Alpair 7.
If I put this project in Winisd with a box of 3,5l everything seems fine, but perhaps there is something that I'm missing in order to make a good sounding speaker.
So every help is much appreciated.

planet10 · 19th June 2011, 06:02 PM

The A7 can be used in quite a small box if you aren't concerned about the bass. If too small you will get a bump at the bottom of the pass-band but this will be crossed out. The biggest concern with a very small box is that of internal reflections coming back thru the cone. This will be less an issue if you make an actual teardrop for the backhalf... if needed you can leave the skinny end open and make it into an aperiodic mid-TL.

Another issue with the smaller bowls is that more of the bowl has to be cut away to get the driver rebated. A quick sketch shows no mecahnical issues, but it will decrease your volume.

dave

Veggiel · 19th June 2011, 06:17 PM

Thanks for the informative answer, I will be making the actual teardrop shape like B&W so hopefully I won't have to much problem with internal reflection.

About the bass driver are the TRIO8's a good match for the alpair 7 or are there better alternatives?

planet10 · 19th June 2011, 06:31 PM

If you can find some Trio8s, they are an excellent woofer with good extention.

dave

18th June 2011, 09:44 AM	#1
Veggiel diyAudio Member Join Date: Jun 2010	Advice for FAST with alpair 7 I want to build a FAST system using the Alpair 7 and Minidsp, the design would be quite similar to the B&W 802 diamond. In the thread of the Blanda speakers Ikea spherical speakers, first build done. there where some interesting ideas of how to make the droplet like B&W does. Now my question is would it be possible to use the 20cm Blanda bowls or do I have to use the 28cm ones? I will most likely cross them at 300hz. So I was thinking that the smaller size bowls should still be ok if the don't have to go that low. For the bass drivers I was thinking of using two CSS TRIO8 drivers per speaker, would these be good drivers for this purpose or are there better alternatives?

18th June 2011, 09:56 AM	#2
DYNABLASTERTUNERS diyAudio Member Join Date: Nov 2009	Instructions on making a spherical enclosure(it's german but you will get the idea) YouTube - ‪WERKANLEITUNG BETONKUGEL‬&rlm; __________________ some of my Designs www.dynablaster.deviantart.com/gallery

19th June 2011, 06:31 PM	#6
planet10 frugal-phile(tm) diyAudio Moderator Join Date: Oct 2001 Location: Victoria, BC, NA, Sol III Blog Entries: 4	If you can find some Trio8s, they are an excellent woofer with good extention. dave __________________ community sites t-linespeakers.org, frugal-horn.com ........ commercial site planet10-HiFi p10-hifi forum here at diyA

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19th June 2011, 04:38 PM	#3
Veggiel diyAudio Member Join Date: Jun 2010	That's an interesting way of building a bowl, but I think I will stick to the Blanda bowls for now. So the question is can I go to Ikea and get a couple of 20cm Blanda bowls to use with the Alpair 7. If I put this project in Winisd with a box of 3,5l everything seems fine, but perhaps there is something that I'm missing in order to make a good sounding speaker. So every help is much appreciated.

19th June 2011, 06:17 PM	#5
Veggiel diyAudio Member Join Date: Jun 2010	Thanks for the informative answer, I will be making the actual teardrop shape like B&W so hopefully I won't have to much problem with internal reflection. About the bass driver are the TRIO8's a good match for the alpair 7 or are there better alternatives?

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