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Multi-Way Conventional loudspeakers with crossovers

Mini-Synergy Horn Experiment
Mini-Synergy Horn Experiment
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Old 28th November 2015, 05:41 AM   #11
chrapladm is offline chrapladm  Australia
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Yay!! Nate is finally tackling a SH.
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Old 28th November 2015, 06:17 AM   #12
AllenB is online now AllenB  Australia
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Nate, where all paths along the walls represent a radius of a sphere where at the centre is a point source, the waves can propagate along them regardless of the cross section that the combined radii form.

Of course horns have other means of action. In some respects square or rectangular has advantages.
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Old 28th November 2015, 03:27 PM   #13
gedlee is offline gedlee  United States
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I am with Nate that the round device is a better match to the compression driver. A square throat with a round CD on it is not ideal. You could go from round to rectangle if done slowly, just like round to elliptical - just nothing abrupt.

Nate - my software can handle any free field time, but of course, as with any software the more time you have the better the LF data will be. But in this case we are not so interested in the LF data anyways.

I am quite interested in the phase response of this design. Of course any design can have flat phase with some DSP added, but it is nice to have it inherently flat.
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Last edited by gedlee; 28th November 2015 at 03:30 PM.
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Old 28th November 2015, 05:03 PM   #14
natehansen66 is offline natehansen66  United States
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Earl - I know we've spoken about this before but just to be clear with my PC setup and the way I have to process audio I cannot get time-lock to work in Holm. You have data posted in your sw of a speaker of mine that was done with no time lock. That is how you would get the data.

I'm not "there" yet with the phase. I had something quite close to linear phase through the xo last night but it required that the compression driver run lower than I wanted to. I'm working on some changes to the mid port/chambers that will hopefully extend mid response and give me a little more room to work with. Of course it would be easy to just do an FIR correction, and the cool thing about the Synergy is it should hold up over all angles.
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Old 28th November 2015, 05:59 PM   #15
gedlee is offline gedlee  United States
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If the time base does not move too much it can be all right, but if it moves a lot then problems will ensue. Send me some data and I'll see what I get.

I only recently started to look at phase in my speakers and I was pleasantly surprised that it was fairly well controlled without doing anything special. Over the bandwidth of 700 - 7000 Hz - the critical range for phase - it varies less than 60 degrees. That's pretty good considering it just happened that way. I have always been conscious of a compact impulse response and the phase shift has to be minimal for that to occur, so perhaps I was forcing a flat phase without even doing it deliberately.
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Old 28th November 2015, 07:49 PM   #16
weltersys is offline weltersys  United States
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Quote:
Originally Posted by Patrick Bateman View Post
Neat!

Here's some things to try to take it to "the next level."
2) Measure the distance from the throat to the midrange taps. Now set the lowpass on the midranges to achieve an acoustic lowpass that's about 3rd or 4th order. The idea is to introduce a delay that's enough to keep the midranges from radiating until the tweeter "catches up"
The band pass mids are acoustically delayed from the HF, and may not require any delay, the opposite may be true.

The HF is physically further from mic but measures .62 millesecond closer in my SynTripP.

The screen shot below shows the combined raw response of the (ported, Fb 81 Hz) cone drivers and the HF driver, note how smooth the phase response is with no delay applied.
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File Type: png SynTripP Raw LF+HF.png (142.0 KB, 691 views)
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Old 29th November 2015, 01:40 AM   #17
AllenB is online now AllenB  Australia
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Quote:
Originally Posted by gedlee View Post
That's pretty good considering it just happened that way.
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Originally Posted by gedlee View Post
I am quite interested in the phase response of this design.
A few years ago I designed a synergy on paper (Akabak) and the response came out like a single wide band source, using only simple filters.
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Old 29th November 2015, 03:30 PM   #18
gedlee is offline gedlee  United States
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Using two diaphragms on a single horn is not so new, BMS has been doing this for a long time (also see Adamson). In those designs it is always easy to find the crossover point between the two diaphragms in both the FR and the polar response - its never ideal. Perhaps it is the very low frequency of the crossover in the synergy that helps this problem.
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Old 29th November 2015, 10:57 PM   #19
AllenB is online now AllenB  Australia
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The blending I saw was uncanny. If Akabak wasn't an arbitrary simulator I'd have assumed there was a mistake somewhere.

Quote:
Originally Posted by gedlee View Post
Perhaps it is the very low frequency of the crossover in the synergy that helps this problem.
Not sure I follow. The designs I was reading about at the time were using the mids to cover the octave below 1500Hz and I didn't see the point in doing that, especially with the assumed disadvantages.

I wouldn't be keen on a design that wrapped the throat around coaxial cones.
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Old 4th December 2015, 11:51 PM   #20
natehansen66 is offline natehansen66  United States
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I made some changes to the port configuration which I'll detail later. For now here's a new xo I worked up. Acoustically it's at about 1.2khz. It could use some more work but not bad really! I don't have as much overlap on the hf and mr that I thought I'd need but I think that phase looks pretty good for a first crack. Didn't take me long to arrive at that.

I also have some open cell throat plugs made for this wg that I use in my main system. My hope was that the foam might "clean up" some of the reflections from the ports (not that I'm seeing much in the way of reflections) due to the longer distance traveled through the foam vs the main wave. Measurements out to 70 didn't show any change other than the normal attenuation.

I just might drag this thing outside this weekend for some better measurements. Sunday looks like 40's with little to no wind.
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File Type: png eoswg synergy phase.png (48.2 KB, 542 views)
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