Jason you're going to run into frequency response issues between your compression driver and your mids. This is because the pathlength difference is significant. For instance, with a gap of 15 centimeters between the two diaphragms, the midrange will be one half of a wavelength "ahead" of the tweeter at 1133hz. That'll create a deep null, right where you don't need one (close to the xover frequency.)
But fear not! You have a miniDSP and you can reduce the severity of the dip by using DSP delay to line up the wavefronts.
If you really wanted to go crazy with this you could use RePhase to have a delay that varies with frequency, but even "basic" delay will make a big difference.
Also, you probably already knew all of this
But thought I'd point it out, in case you do a frequency response measurement and you see a big ol' null
But fear not! You have a miniDSP and you can reduce the severity of the dip by using DSP delay to line up the wavefronts.
If you really wanted to go crazy with this you could use RePhase to have a delay that varies with frequency, but even "basic" delay will make a big difference.
Also, you probably already knew all of this
But thought I'd point it out, in case you do a frequency response measurement and you see a big ol' null
"Basic" delay does it all when you also EQ the drivers flat first (and there is no reason not to when you're using DSP). There is that other null problem/feature discussed earlier, but no reason to keep on with estimating how that part pans out since it's happening here .
.Right on, but I hope you do a bunch of individual measurements of the waveguide and the cone drivers on just a single side first.
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"Basic" delay does it all when you also EQ the drivers flat first (and there is no reason not to when you're using DSP). There is that other null problem/feature discussed earlier, but no reason to keep on with estimating how that part pans out since it's happening here
Right on, but I hope you do a bunch of individual measurements of the waveguide and the cone drivers on just a single side first.
Does it?
I would expect that the impedance peaks in the response of the compression driver will introduce a delay.
I know that's one of the reasons we *don't* need a delay when building a Synergy Horn. The midranges lead the compression driver, but the rise in impedance that's caused by using a very small back chamber has the effect of virtually moving the midranges backwards, closer to the compression driver.
When I messed around with cardioid Synergy horns, this was one of the headaches I had to deal with; because there's no back chamber we don't have that effect of 'virtually' moving the midranges backwards.
But I don't have a really strong grasp on phase, so I may well be talking out my a ss
Also, you probably already knew all of this
Yes I did.
But it's good for those who are reading these forums that are just starting out.
So, good call!
If I'm not mistaken, this is why it took years and years and years for a Synergy horn to be released that used a single driver at the apex.
An externally hosted image should be here but it was not working when we last tested it.
It wasn't until BMS released this woofer that there was a coax that had the right combination of attributes.
Technically, there's some synergy horns that use 8" coaxes, but those horns use them in a direct radiator setup
Nice!
How are you wiring the 12 drivers? 4 series 3 parallel?
3 series, 4 parallel.
For 6 ohms nominal.
Get more power this way.
I'm not going to pretend I'm certain how all the variables in the Synergy result in what it is, but I'm guessing that was just a convoluted (to me) way of explaining that the phase shift corresponding to the response of the high-Q enclosure is affecting the phase you're starting with when you set out to juggle the driver locations and entrances and passive filter and everything to add up to a Synergy horn. Tricky business.
Here in DSP land, you can start from very wide and widely-overlapping bandwidths of flat response and correspondingly flat phase.
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Build 3 separate speakers
What's the point of building 3 seperate speakers?
If this were beneficial than it could be done with existing 5.1 systems, with the matrixing capabilites already existing in any HT reciever with dolby pro logic 2.
I thought the benefit was to have a more diffused L & R soundfield with a delayed time arrival?
I have a L R C matrixed setup in my car and it doesn't bring any magic to the table.
Improved imaging compared to 2 speaker stereo.
Yes it is a benefit, and that you will get with your plan.
However, if you wish to reproduce images from stereo panning you may need to alter something in your plan.
I have my doupts, but don't let it slow you down
What matrix is that ?
Oujes the delay of reflections will create a lack of side images. I think it can be compensated by dsp but only at frequencies above baffle step. Low freqs added delay creates weird phasing effect, which _could_ improve spaciousness even further
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