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Old 22nd June 2013, 05:32 PM   #21
DrDyna is online now DrDyna  United States
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AH, ok. It's at 26" right now, I can scoot it out a bit if I need to. Going to run up and get some more gator clips, I seem to have run out!

Testing will resume shortly.

Thanks for all the help guys, I need to name these things after all of you, right now I've only been referring to them as "the grumpy cats".
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Old 22nd June 2013, 10:21 PM   #22
puppet is offline puppet  United States
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Originally Posted by picowallspeaker View Post
You said that you don't like resonances, but I see all the drivers attached by the baskets.
Why don't you suspend 'em with rubber bands ?
Really only one driver is attached by it's basket ... the 12", the 15" is resting on a concrete slab with a simple magnet clamp, the 5" is suspended off the heil, heil is suspended off the frame.. ... but as you said I'd like to try suspending all of them a bit differently
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Old 23rd June 2013, 05:44 PM   #23
DrDyna is online now DrDyna  United States
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What values do you guys use for tweeter protection caps, if you use any at all? Do you think 12uF is good enough?
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Old 23rd June 2013, 06:15 PM   #24
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Originally Posted by puppet View Post
Really only one driver is attached by it's basket ... the 12", the 15" is resting on a concrete slab with a simple magnet clamp, the 5" is suspended off the heil, heil is suspended off the frame.. ... but as you said I'd like to try suspending all of them a bit differently
The torque on the frame will be immense if he's only holding by the lateral holes.

EDIT: I see he is daisy-chaining holes. He'll have to build compliance into the structure due to tolerance stack-up.

Last edited by 454Casull; 23rd June 2013 at 06:24 PM.
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Old 23rd June 2013, 06:21 PM   #25
Rudolf is online now Rudolf  Germany
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We used 10 µF, 0.12 mH and 22 µF as a third order HP for the Neo3. 12 µ is ok as a 1st order cap.
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Last edited by Rudolf; 23rd June 2013 at 06:31 PM. Reason: Got the direction of increasing/reducing the value wrong
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Old 24th June 2013, 02:52 PM   #26
DrDyna is online now DrDyna  United States
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Well, this is certainly an interesting effect. Currently with a very terrible passive crossover (I haven't obtained my second miniDSP yet, I'm on the fence about ordering another one or ordering a DCX2496) they have a really neat ability to defy their position. I flopped down on a chair that's pretty much in line with the left channel, yet I didn't really get any image leaning that I'd normally expect..and walking around in the room doesn't really "warp" the FR like I'm used to with box speakers.

They do seem a little thin sounding, but that's probably my hodgepodge passive crossover at work.

I'll attach what I was able to achieve with my single MiniDSP working on just one channel.

Cost aside, what's the general opinion in DCX2496 vs 2x 2x4 MiniDSP? I understand the Behringer unit probably offers a little more output, but the flexibility seems similar.
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Old 24th June 2013, 06:32 PM   #27
DrDyna is online now DrDyna  United States
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The experiment has evolved into a hybrid of sorts, using the MiniDSP for the mid and tweeter, with an 8.5mh / 250mfd on the woofer. Measured, that rolls it off very gracefully around 12db/oct starting around 400 hz.

Is it just me or does the MiniDSP sound terrible with more than about a quarter of a volt of input?

The purchase decision is definitely swinging toward the Ultradrive.
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Old 24th June 2013, 06:35 PM   #28
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Originally Posted by DrDyna View Post
The experiment has evolved into a hybrid of sorts, using the MiniDSP for the mid and tweeter, with an 8.5mh / 250mfd on the woofer. Measured, that rolls it off very gracefully around 12db/oct starting around 400 hz.

Is it just me or does the MiniDSP sound terrible with more than about a quarter of a volt of input?

The purchase decision is definitely swinging toward the Ultradrive.
It's just you, or how you are using it. Check all levels. Internal level should never go above 0dB, so if you are applying any combination of boost or EQ that totals more than about 12dB at any frequency, then you are likely exceeding the maximum internal levels. This is why I was arguing for 10dB-20dB gain stages after the MiniDSP - so you can reduce the gain inside the MiniDSP (e.g. at the input in this case) and then get back gain in the analog domain.

-Charlie
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Old 24th June 2013, 07:57 PM   #29
Juhazi is offline Juhazi  Finland
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I've been using minidsp for 2 moths now. It starts buzzing sometimes after I save my settings (during measuring session). And you must be careful not to push it over 0dB total. It is teasingly easy to add gain in PEQ settings, but after xo settings you must be on negative values. A dipole needs lots of shelving eq which lead to lower efficiency in bot passive and digital-sp systems. Adjustable gain at analog stage is nice. I use B&O ICEpower modules 50 and 125 - this is my way of compensating this (difference perhaps 6dB)

Another issue mentioned earlier was to not use double mids in a dipole system. I don't agree! I measured my AINO today out with and without second serial high-mid. Seems like they have similar dipole behaviour in my system, but a single mid has shaper reflections and sharper reverse null - more precise phase behaviour measured with a microphone at a spesific point (I didn't try to adjust it in single version) I haven't yet listened WMT inside vs. WMTM, but outside I couln't hear a difference. We must remember that a muldtidriver dipole alwasy has deteriorating reflections on the backside from orther drivrs' bodies. It can't be avoided.

Click the image to open in full size.

Click the image to open in full size.

Here are vertical polar simulations of a MT an a MTM with 100mm distance M-T that I made for AINO (MTM looks better to me)
Click the image to open in full size. Click the image to open in full size.
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Last edited by Juhazi; 24th June 2013 at 08:13 PM.
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Old 24th June 2013, 08:21 PM   #30
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Originally Posted by Juhazi View Post
Another issue mentioned earlier was to not use double mids in a dipole system. I don't agree! I measured my AINO today out with and without second serial high-mid. Seems like they have similar dipole behaviour in my system, but a single mid has shaper reflections and sharper reverse null - more pricise phase behaviour measured with a microphone at a spesific point (I didn't try to adjust it in single version)
Thanks for posting about your experiences. It seems to me that many people experience this problem with OB systems or LT boosted subwoofers and don't know that internal (digital) levels that are pushed too high cause obvious distortion. They just think that the product sounds crappy!

I wanted to comment on what you said about dual midranges: anytime you have two drivers separated by more than about 1/4 to 1/2 wavelength the off axis response will have nulls. The transition to where this starts to happen is at a frequency that corresponds to about 1/4 wavelength, and as you go up in frequency the number of nulls increases and the "pattern" narrows. If you only measure directly on axis from a point in between the two drivers you will not see this behavior. This is because the nulls occur when the pathlengths driver-A --> listener and driver-B --> listener happen to equal 1/2 wavelength and the phase is 180 degrees different. But on axis the pathlength to each driver is the same, so interference is not observed. Besides being "box less", the open baffle should radiate power into the room evenly because you are hearing more sound reflected by the room in an OB speaker, so you don't want off-axis nulls. In general this is always a bad thing IMHO, but if you only listen on axis and the speakers sound OK in your particular listening environment the "problem" may sufficiently benign to be ignored. But in general it's a good practice to avoid it.

-Charlie
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