Hi,
I just fitted the Omnes L8 to a sheet of MDF, 600x1200x16.
Driven by Bryston powerpac 120's, Audionote kit pre, and a Keces usb dac from the pc.
The sound was very ordinary to start with, but with some tweaking of the EQ in J. River, I was able to get the sound really good.
I had to turn up the lower frequencies and this made everything click.
I've added a Infinity emit tweeter with a 7uf cap in line to it.
Nothing special to look at, I'll sort that out once I've got it sounding spot on.
I'm after some help on what woofers to fit. From what I've seen using the Eminence 15" alpha is a great choice, but these aren't available to me in Australia (I can't find anyone that has it), I can get the Beta's at $350 for 4, but these would probably need more work in regards to amplifying.
Or I can get some cheap chinese 12" drivers $35 each, specs -
Paper Cone.
Foam Surround.
Z 8W (9.2Wdc)
Freq. 27®3KHz
Fo 36Hz
Sens’ 90dB
Magnet 13 Oz
Voice 32mm
Power 50W nom.
Qms 4.39
Qes 2.07
Qts 1.40
Vas 276.77L
Any help would be appreciated.
I just fitted the Omnes L8 to a sheet of MDF, 600x1200x16.
Driven by Bryston powerpac 120's, Audionote kit pre, and a Keces usb dac from the pc.
The sound was very ordinary to start with, but with some tweaking of the EQ in J. River, I was able to get the sound really good.
I had to turn up the lower frequencies and this made everything click.
I've added a Infinity emit tweeter with a 7uf cap in line to it.
Nothing special to look at, I'll sort that out once I've got it sounding spot on.
I'm after some help on what woofers to fit. From what I've seen using the Eminence 15" alpha is a great choice, but these aren't available to me in Australia (I can't find anyone that has it), I can get the Beta's at $350 for 4, but these would probably need more work in regards to amplifying.
Or I can get some cheap chinese 12" drivers $35 each, specs -
Paper Cone.
Foam Surround.
Z 8W (9.2Wdc)
Freq. 27®3KHz
Fo 36Hz
Sens’ 90dB
Magnet 13 Oz
Voice 32mm
Power 50W nom.
Qms 4.39
Qes 2.07
Qts 1.40
Vas 276.77L
Any help would be appreciated.
Scrappydoo
maybe you would like to look at another project with the L8. You don´t need to read it (it´s all in German). Just look at the beautiful craftsmanship. Should make you really envious.
In post #22 I show a passive filter to raise the low frequencies of the L8.
maybe you would like to look at another project with the L8. You don´t need to read it (it´s all in German). Just look at the beautiful craftsmanship. Should make you really envious.
An externally hosted image should be here but it was not working when we last tested it.
In post #22 I show a passive filter to raise the low frequencies of the L8.
Rudolf said:Scrappydoo
maybe you would like to look at another project with the L8. You don´t need to read it (it´s all in German). Just look at the beautiful craftsmanship. Should make you really envious.
An externally hosted image should be here but it was not working when we last tested it.
In post #22 I show a passive filter to raise the low frequencies of the L8.
Thanks Rudolf, all the photos have gone from excess d/l
Just an update, I grabbed the eminence drivers from gainphile (thanks).
Fitted them to the baffle and cut it down to 400mm at the top for the omnes driver and left it at 600mm for the 15" drivers.
I'm going to do active crossover and bi-amp it.
Please don't look to hard at my woodworking skills.
Fitted them to the baffle and cut it down to 400mm at the top for the omnes driver and left it at 600mm for the 15" drivers.
I'm going to do active crossover and bi-amp it.
Please don't look to hard at my woodworking skills.
Eminence Betas are eminently suited to sit in H-baffles. That will sink Fs a bit and equalize response with the choice of a suitable crossover frequency. Read MJK's excellent paper: http://www.quarter-wave.com/OBs/U_and_H_Frames.pdf .
Put two Betas in parallel in an H-frame 40(w) x 80(h) x 40(d) cm (inner measures).
Cross them over with a LR-filter 10 mH 160 uF then put the Omnes above on a separate baffle and please the magnetostat above it. Crossover for the Omnes LR should be 47 uF and 9 mH and you are home. No EQ will be necessary, 30 Hz about - 5 dB, average SPL/2.83 volts 95 dB, all passive.
/Erling
Put two Betas in parallel in an H-frame 40(w) x 80(h) x 40(d) cm (inner measures).
Cross them over with a LR-filter 10 mH 160 uF then put the Omnes above on a separate baffle and please the magnetostat above it. Crossover for the Omnes LR should be 47 uF and 9 mH and you are home. No EQ will be necessary, 30 Hz about - 5 dB, average SPL/2.83 volts 95 dB, all passive.
/Erling
skorpion said:
How did you come up with those values for the Omnes? When evaluating the OB linked above, we simulated two Betas in conjunction with the L8 on a 43 cm wide OB and found this crossover to simulate best:
An externally hosted image should be here but it was not working when we last tested it.
A 9 mH coil (parallel to the L8) in place of the voltage divider looked much worse. Maybee Scrappydoo should try our approach before investing in that 9 mH coil
For the combination of L8 and Alpha 15 we found this crossover to simulate best:
An externally hosted image should be here but it was not working when we last tested it.
The 56µF cap is only necessary if the Alpha's 2 kHz peak should need further attenuation.
I read too fast, I suppose. 
If you bought Alphas from gainfile things are even easier. You could do about the same as I have with the MJAO G 098: http://www.audiocircle.com/circles/index.php?topic=65570.0 for the crossover. A simple 6 dB/octave will do with a 2 mH coil for the Alpha and a 60 uF capacitor on the L8. No EQ will be necessary. You could even cut the baffle to 40 cm width or put some small wings if you want it wider.
The Infinity Emitter seems to come in a bit low, I would aim at crossing around 8-9 kHz in the first place.
Good luck !
/Erling
If you bought Alphas from gainfile things are even easier. You could do about the same as I have with the MJAO G 098: http://www.audiocircle.com/circles/index.php?topic=65570.0 for the crossover. A simple 6 dB/octave will do with a 2 mH coil for the Alpha and a 60 uF capacitor on the L8. No EQ will be necessary. You could even cut the baffle to 40 cm width or put some small wings if you want it wider.
The Infinity Emitter seems to come in a bit low, I would aim at crossing around 8-9 kHz in the first place.
Good luck !
/Erling
Hi Rudolf,
So we are working with the same aim. I suppose Scrappydoo could be worse off.
1st for the H-baffle combo with Betas I calculated standard LR crossovers for Betas and L8. Betas crossed about 125 hZ and Omnes in the 200 - 250 range where the H will start to fall sharper. May be 47 uf and 10 mH would have been even better. I actually used K&T's measured impedance for the L8.
2nd in the Alphas case I would start mimicing my own MJAO as stated above, aiming for a common crossover region 300 - 350 Hz.
Evidently I would put crossover a bit higher than you. It is probable that L8 will need some attenuation.
/Erling
So we are working with the same aim. I suppose Scrappydoo could be worse off.
1st for the H-baffle combo with Betas I calculated standard LR crossovers for Betas and L8. Betas crossed about 125 hZ and Omnes in the 200 - 250 range where the H will start to fall sharper. May be 47 uf and 10 mH would have been even better. I actually used K&T's measured impedance for the L8.
2nd in the Alphas case I would start mimicing my own MJAO as stated above, aiming for a common crossover region 300 - 350 Hz.
Evidently I would put crossover a bit higher than you. It is probable that L8 will need some attenuation.
/Erling
Hi
Very interesting
Which Omnes L8 do you use
Breitbandlautsprecher sell two versions, one of which is with copper sleeve, custom made fore them ?
I am considering to use it with Beyma 12AG100 (100db)
But maybe the Beyma will do better on its own
Could also consider double SENON 12" or Spectrum BB250 fore midbass with the L8
New AN 15" will unfortunately be much too expencive
Expect to use a boxed 18" sub as well
Very interesting
Which Omnes L8 do you use
Breitbandlautsprecher sell two versions, one of which is with copper sleeve, custom made fore them ?
I am considering to use it with Beyma 12AG100 (100db)
But maybe the Beyma will do better on its own
Could also consider double SENON 12" or Spectrum BB250 fore midbass with the L8
New AN 15" will unfortunately be much too expencive
Expect to use a boxed 18" sub as well
skorpion said:Hi Rudolf,
So we are working with the same aim. I suppose Scrappydoo could be worse off.
My L8 data are from hifi-selbstbau.de. I was trying to get along with as few crossover parts as possible. The crossover region for the Alpha/Beta 15 combinations looks like this:
An externally hosted image should be here but it was not working when we last tested it.
Full lines are Beta, dotted lines Alpha. As you can see, the 2 kHz peak of the Alpha does not show because it is not part of the TSP. For the L8 complete frequency and impedance measurement data were taken. Please note that the FR driver has opposite polarity.
My simulations are for the standard L8 (without copper sleeve)
Scrappydoo said:
It was not my intention to annoy you
I do know that the sleeved version is only available in EU
I was approaching the EU members here, drawing attention to this copper sleeved option
You could try a small zobel across L8 terminals instead...might work too
Why a dedicated and dead serious german doesnt use the sleeved version, thats really beyond me
Or maybe I was just looking fore a plausible reason
Or could be that all L8 have a pole sleeve by now...they cost the same
Though SpectrumAudio list slightly different specs and response
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