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8 Pi speakers [message #44702] Wed, 02 June 2004 22:21 Go to next message
wasteh202 is currently offline  wasteh202
Messages: 137
Registered: May 2009
Master
Wayne

I have not followed closly the creation of the 8 Pi speaker, but I must say that it looks interesting.
I have searched the forum and read the material there, but I am still lacking in some information.

Are you packaging the Kits yet, are you shiping out the plans yet ?

Also, do you have any posted specs on the speakers ?

Thanks, Rodney

Re: 8 Pi speakers [message #44703 is a reply to message #44702] Thu, 03 June 2004 01:15 Go to previous messageGo to next message
Wayne Parham is currently offline  Wayne Parham
Messages: 18786
Registered: January 2001
Illuminati (33rd Degree)
Nope, no and nope. But soon.

Actually, a prototype was built that proved the point and as you probably saw, other people are already building them from preliminary information. The first one out of the gate was Duncan McBride, who built an excellent looking pair.

Kits are available now, inasmuch as the crossovers are worked out and cables assemblies have been put together, so that's all nailed down. We maintain stock of the speaker drivers and most of the crossover electronics, so that part is ready. We're still waiting for inventory on one of the coils. But I still haven't finished the drawings to make the plans. I worked on them today, so it shouldn't be long before I have distribution copies of the plans available.

Re: 8 Pi speakers [message #44704 is a reply to message #44703] Thu, 03 June 2004 08:31 Go to previous messageGo to next message
Wasteh2202 is currently offline  Wasteh2202
Messages: 2
Registered: May 2009
Esquire
Wayne

Thanks for the info. I will watch for the info to hit your website and this forum. After building two pairs of 2Pi Towers I am in not hurry to build another pair of boxes right now. However, I am anxious to hear this combination of drivers in the enclosure that you have disigned.

Got any specs you can give on the sensivity and the frequency range ? Also the cab size ? Thanks !

Re: 8 Pi speakers [message #44705 is a reply to message #44704] Thu, 03 June 2004 13:38 Go to previous messageGo to next message
Wayne Parham is currently offline  Wayne Parham
Messages: 18786
Registered: January 2001
Illuminati (33rd Degree)
It's 5.5ft3 and 97dB/W/M from 35Hz to 16kHz when placed in corners or against the wall.

Re: 8 Pi speakers [message #44706 is a reply to message #44705] Thu, 03 June 2004 14:24 Go to previous messageGo to next message
Matts is currently offline  Matts
Messages: 359
Registered: May 2009
Grand Master
Wayne,

Any plans to design a similar cab for a 12" or 15" woofer? Do the mids from the 10" make it better for this type of design?

Matts

Re: 8 Pi speakers [message #44709 is a reply to message #44705] Thu, 03 June 2004 19:21 Go to previous messageGo to next message
wasteh202 is currently offline  wasteh202
Messages: 137
Registered: May 2009
Master
thanks Wayne...

I was hoping that it would be a bit more senstive than 97db. I guess the increase in sensitivity from the PSD2002 is reduced by the addition of an XO ... No ?

I'm still interested, my ears are still good... so I really don't need much more than 1 watt.

Re: 8 Pi speakers [message #44711 is a reply to message #44709] Thu, 03 June 2004 23:49 Go to previous messageGo to next message
Wayne Parham is currently offline  Wayne Parham
Messages: 18786
Registered: January 2001
Illuminati (33rd Degree)
The midrange and treble is reduced in efficiency to the level of the bass below 100Hz. Not only is the region below 100Hz augmented but also the region above 8kHz. This passive compensation EQ reduces sensitivity about 10dB but increased dynamic range provided by horn loading is retained. Said another way, maximum output is about 10dB higher because of horn loading.

Some might wonder what is gained by using a horn to increase acoustic output by 10dB when electrical energy is reduced by 10dB. On first glance, it would appear that the net result is no change. But distortion is decreased, and dynamic range is increased. The system sensitivity remains the same in an implementation like this, but maximum output is increased and distortion is reduced.

Re: 8 Pi speakers [message #44712 is a reply to message #44706] Fri, 04 June 2004 00:01 Go to previous messageGo to next message
Wayne Parham is currently offline  Wayne Parham
Messages: 18786
Registered: January 2001
Illuminati (33rd Degree)
I hadn't really considered it but I also wouldn't rule it out. Something like a Magnum 12 in a cabinet like this using a larger horn and a 2" compression horn might make a good system. One problem that would need to be solved is that 2" compression drivers usually don't reach beyond 10kHz, so an additional tweeter would probably be desired. Another is finding a 12" midwoofer that would perform well through the midrange and be suitable for a woofer in a reasonably large vented back chamber.

Most of the midwoofers that come to mind are tuned so that they work best in small vented cabinets having fairly high cutoff. They could be put in a larger cabinet to yield an EBS alignment, but the shelved response resulting from the lack of horn loading in the bass plus additional reduction in bass from an EBS alignment in the vented rear chamber would probably yield too little bass to be really useable. In short, most of the good 12" drivers I'm thinking of are better used as midrange drivers than for something like this.

What we really need is to sweet talk Eminence into a driver tuned like the Alpha 10 but with a powerful motor having a shorting ring. Sort of a Magnum 10 with tuning like the Alpha 10. Eminence loves to be sweet talked like this, especially with a purchase order in hand. We'd need to commit to a hundred units and they'd be happy to make 'em for us. That's something to think about. A 400 watt Magnum 10.

Re: 8 Pi speakers [message #44714 is a reply to message #44711] Fri, 04 June 2004 00:10 Go to previous messageGo to next message
wasteh202 is currently offline  wasteh202
Messages: 137
Registered: May 2009
Master
That helps me alot. Wayne, thank for the great explanation on how this works.

I really think the cabs for the Thermonic 8 will challange my woodworking skills. Perhaps I can find a craftsperson to build them for me.

Anyway... I'll be looking for the plans when they are available.

Thanks

Listening to Pi 8s yet? [message #44717 is a reply to message #44702] Sat, 05 June 2004 07:28 Go to previous messageGo to previous message
GarlandGarland is currently offline  GarlandGarland
Messages: 60
Registered: May 2009
Viscount
Has Duncan finished and listened to his 8s yet?

Garland

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