Cheap and FAST OB, Literally

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#81
Toaster said:
That's a really creative use of low cost components and materials xrk. Very clever indeed!
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Thanks, Toaster!

I recently discovered an 8 inch polycone woofer from PE made by GRS that has Qts of 1.15 with 3mm xmax for $10 ea in qnty of 4 or more. I think running 8 of those per side in a slot loaded woofer will give 97dB at 4 ohms with 2.87v input. That opens up capability of pairing with open back pleated mid/tweeter or higher efficiency fullrange like a 91 dB Faital Pro 4FE35.

Hmm....
 
#82
GRS 4FR-8 4.5 inch full range driver for $8.20?

Has anyone tried one of these budget full range drivers from PE? I just ran across this for the first time. It has 91dB efficiency and Qts of 0.82 - perfect for OB top driver above 200 Hz. The xmax is obly 1 mm but that isn't a problem if used as the 200 Hz and above top in either an OB, or maybe even a Nautaloss monitor.

GRS 4FR-8 Full-Range 4-1/2" Speaker Pioneer Type A11EC80-02F | 292-434

An externally hosted image should be here but it was not working when we last tested it.
 
#85
#86
The GRS 12PR-8 in qnty 1 still does not have enough surface area for a balanced amount of bass with the Vifa. If you want to use a single woofer go with a 15 in GRS - which is what the Manzanita uses. You need 6 x 6.5 in drivers, or 4 x 8 in drivers, or 2 x 12 in drivers, or 1 x 15 in driver.

You should get this driver if you want to keep it simple to pair with the Vifa Tc9fd. GRS 15PF-8 15" Paper Cone Foam Surround Woofer | 292-415
 
#87
xrk971 said:
The GRS 12PR-8 in qnty 1 still does not have enough surface area for a balanced amount of bass with the Vifa. If you want to use a single woofer go with a 15 in GRS - which is what the Manzanita uses. You need 6 x 6.5 in drivers, or 4 x 8 in drivers, or 2 x 12 in drivers, or 1 x 15 in driver.

You should get this driver if you want to keep it simple to pair with the Vifa Tc9fd. GRS 15PF-8 15" Paper Cone Foam Surround Woofer | 292-415
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So, 2 twelves may be an option, hmmmm

I am planning on the Mazanita (original w/ with the Peerless 12), but was thinking of trying something on the cheap in the mean time. Maybe I'll check the mounting diameter of the Peerless and see if I can find an inexpensive 12" with the the same cut out to drop in for now - since the Peerless in OOS.

Thank you for helping me bench race.
 
#88
BeauB said:
So, 2 twelves may be an option, hmmmm

I am planning on the Mazanita (original w/ with the Peerless 12), but was thinking of trying something on the cheap in the mean time. Maybe I'll check the mounting diameter of the Peerless and see if I can find an inexpensive 12" with the the same cut out to drop in for now - since the Peerless in OOS.

Thank you for helping me bench race.
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The latest Manzanita design uses the GRS15 I thought.
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#89
xrk971 said:
The latest Manzanita design uses the GRS15 I thought.
image.php
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There are two versions. The original Mazanita uses the Peerless 12" coupled with the Vifa 3.5".

The designer later came out with a lower cost targeted model (referred to as the Ultra - for ultra low cost) that uses the GRS 15 coupled with the Vifa 3.5".

I am told that although the Ultra sounds great, the original design sounds much nicer - and the difference in baffle size between the two is significant (the Ultra using a MUCH larger baffle).
 
#90
Would this work in Open Baffle?

I have two 12 inch per side and a pair of monacor full range 8 inch 200X/4

Seems like it would fit on a sheet of foam core 🙂

Thinking of a skeletal rear to hold the drive units made from spare chipboard loft boarding cut with a jig saw...
 

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#91
jonnoshore said:
I have two 12 inch per side and a pair of monacor full range 8 inch 200X/4

Seems like it would fit on a sheet of foam core 🙂

Thinking of a skeletal rear to hold the drive units made from spare chipboard loft boarding cut with a jig saw...
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That looks like a very nice combination actually since the Monacor SP200X/4 is 94 dB efficient and has a large Qts of 0.97 - perfect for OB.

I am not sure which Beta 12 you have - looks like it may be the coaxial? The Eminence Beta 12's (depending on variety CX, A, or LTA) are all about 0.5 Qts which is a moderate Qts that can work with some EQ'ing given that the xmax is 3.5mm. Since they are 8 ohms putting them in parallel will give you 4 ohms to match the 4 ohm Monacor top and boost the efficiency to ~102dB at 2.83V - providing lots of room to EQ down to match the Monacor.

These are all pretty heavy drivers - you will need that chip board to support the weight - or maybe 3 or 4 layes + double layer cardboard backing.

With DSP and bi-amping you should be able to tweak the EQ and XO to work out pretty nicely. It will probably take some EQ boost in the 40 to 50 Hz range to get bass out of it.

Good luck!
 
#93
Inspiring stuff again...

I've not yet heard an open baffle speaker in action and reading this thread, plus a few of the other resent cheap OB projects, I'm in the mood to try it out for myself... Also, having the miniSharc means I can now play about a little more 🙂

Most UK stockists only have the more expensive range of drivers, so I'm going to turn to Conrad UK for a 3" FR and 8" woofer... budget of £60 should cover everything I need... be interesting to hear how they perform in the near/mid field position.

Paul
 
#94
BuildMeSomething said:
Inspiring stuff again...

I've not yet heard an open baffle speaker in action and reading this thread, plus a few of the other resent cheap OB projects, I'm in the mood to try it out for myself... Also, having the miniSharc means I can now play about a little more 🙂 l
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Did you listen to the sound clips? Now you can hear an OB in action 🙂 The miniSHARC (or miniDSP in my case) has really made it so easy to try out 2-way systems and FAST implementations.

http://www.diyaudio.com/forums/full-range/249984-cheap-fast-ob-literally-8.html#post3807593

Good luck on your hunt for budget drivers. I think you can get Vifa TC9FD's in Europe easily enough. Great driver - very low distortion with great smooth mids and enough high end sparkle.
 
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