planet10 said:
I like the FR and extra couple dB sensitivity of the 126. However, I was wondering about the low Q and thinking it may be a tad bright.
The 127 has a couple more peaks and dips, but shielding makes it more versatile.
I will be happy with either one.
The 127 is about $1 more than the 126 so price difference does not really matter.
It looks like we are leaning towards the FE127E.
I say we move on to selecting an enclosure.
I like the idea of a slim rectangular ported box with the driver located about 36" off the ground.
My reasoning, slim is attactive and would likelky pass a wife test. Rectangular is easy to build, and 36" seems like a reasonable ear height when sitting.
I also think we should try cover as much of the sound spectrum as possible so a bipole would enable us to increase the low end.
Regards,
Gio.
Josephjcole said:127 does seem like a good choice. My friend has asked me to build her a set of speakers, so she might just get a pair of 127's. Although just to add my two cents, I would prefer not to go bi-pole since this would double the cost. Maybe I'm just a cheapskate thou'
Joe
Initially, I had the same thoughts. However, a BSC complicates the project significantly. I have the feeling that the BSC would be amplifier dependent with SS amps requiring higher resistance than a tube amp. In that case, you can argue that it may not be a reference project.
The bipole does a couple of things. It gives more low end and increases the SPL making the project tube friendly.
Anyway, my 2 cents.
Gio.
Now that it appears we have a driver, maybe we should all post links to projects that use the 127 or similar fullrange driver, and think about them. There is no reason we have to do only one design. In fact I propose we first do 2 designs- a bipole, and one with a single driver. Maybe they are basically the same design - one with BSC filter, one with 2 drivers and a bigger box. Or maybe each completely different
Here is v0.1 drawing of Tim's suggested ML-TL. Since it has the driver a 50% this could be elegantly folded -- particularily interesting for the monopole version... i'll have to dig out Denson's paper and do it mathematically proper instead of the usual guess & by golly method.
dave
dave
Attachments
Monkey-works time!
Why not use a combination of an omni with direct raditor? This way you could get a LOT more bass at less cost WITH-OUT a crossover - allowing 16 ohm or 4 ohm impeadance (assuming both drivers are 8 ohms). Additionally you'll be able to use the BEST driver for the money for your upper-mids and tweets and perhaps even shape the rear of this driver for better sound.
Why not use a combination of an omni with direct raditor? This way you could get a LOT more bass at less cost WITH-OUT a crossover - allowing 16 ohm or 4 ohm impeadance (assuming both drivers are 8 ohms). Additionally you'll be able to use the BEST driver for the money for your upper-mids and tweets and perhaps even shape the rear of this driver for better sound.
planet10 said:
Hi Dave,
Have you compared a bipole version( 2 opposite drivers in phase) vs dipole(2 opposite drivers out of phase). Friends and I just put together a 2 pairs of Coral Flat 8 in a BR box and the result was most interesting. The bipole had good bass and midrange was a wee bit cloudy and slight boxiness. In the dipole, wow huge soundstage but centre fill wasn't that good. Maybe because of the almost isobarik type loading the clarity and highs also improved quite a bit. We then tried reducing the high frequency from the rear driver, the centre fill did improve quite a bit and btw the dipole version had less bass.Still experimenting but dipole with subwoofer seems like a good solution.
BTW, Help me understand you. Could the effects you noted be remnants of the cancellation inherent in dipole speakers in general? I'm sure I don't understand, but my first thought is that this is exactly the opposite of what we're trying to do by going bipole in regard to BSC, and the effect you liked (soundstage) is what the OB rage is about.
Scott, Come again? This time for us dummies. Please?
Dave, "Elegantly folded"? I like the sound of that. What sort of bass are we expecting? I'm imagining a rather deep, narrow box that's only about 18-24" tall sitting on it's own matching sub for a stand. Go ahead, tell me the sub won't be necessary.
Scott, Come again? This time for us dummies. Please?
Dave, "Elegantly folded"? I like the sound of that. What sort of bass are we expecting? I'm imagining a rather deep, narrow box that's only about 18-24" tall sitting on it's own matching sub for a stand. Go ahead, tell me the sub won't be necessary.
x. onasis said:
Yes, I think the big soundstage effect is due to the dipole, "open baffle" type effect. The speaker box we did had 2 pair of terminals each so we could try bipole, dipole, 4 ohm, 16 ohm,... connections etc. We did some swaping around and dipole consistently gives biggest soundstage with least bass and sure does sound very OB like. Actually we were quite surprised by the dipole result, our orginal idea was to see how much the bipole would eliminate the baffle step problem. The dipole arrangenent was done just for kicks and were we surprised.
