Open Aire Aktiv build thread

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jimbones

Re: Open Aire Aktiv build thread
« Reply #60 on: 2 Sep 2017, 08:41 pm »
You may need to work with the phase control to get them to sum at the crossover point and create a flat response.

Make sure the amp controls for the low pass are in the EXT/12 position.

You can also work with the gain control to increase overall output (thus increasing the crossover point) and see where that gets you.

Be sure you are measuring only one side at a time. If you try to measure both channels at the same time then you will get a cancellation and peak somewhere.

Try different measuring distances to see if it room related.

If you can post the measurements of the woofers, the upper, and the sum of the two.

Danny,

I will try the phase control again, but I believe I tried that and it didnt help much. I omly have one speaker on at a time. Confirmed I am in the AVR position. As far as the gain, if I bring it up then it will be too loud compared to the toppers. But I will give it a go. I was measuring at about 1 meter from the baffle. I'll measure from the listening position. But I did want to confirm that the amp does not go much higher than 150 hz, correct?



mid only




woofer only

I'll try to get the sum of the two so you can see.


bdp24

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Re: Open Aire Aktiv build thread
« Reply #61 on: 3 Sep 2017, 02:16 am »
Just to confirm the obvious Jim, your Rythmik A370 plate amps are the OB/Dipole version, with the shelving circuit built in?

jimbones

Re: Open Aire Aktiv build thread
« Reply #62 on: 3 Sep 2017, 02:18 pm »
Damn, I hope so I bought them from Danny for the H Frames and bought them together with the woofers. How would I tell by looking at them??

Danny Richie

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Re: Open Aire Aktiv build thread
« Reply #63 on: 3 Sep 2017, 07:37 pm »
Quote
I was measuring at about 1 meter from the baffle.

Ah, there's your problem. 1 meter away is too close for measuring below 200Hz. You'll have to back off to the listening position for ranges below 200Hz.

jimbones

Re: Open Aire Aktiv build thread
« Reply #64 on: 3 Sep 2017, 10:32 pm »
OK ill back up to about 8-10 ft. Danny, I sent you an email. I was able to wire up the servo 2 ways and it seems to work either way but something tells me only one way is correct. you'll see in the diagrams i sent. Thanks.

jimbones

Re: Open Aire Aktiv build thread
« Reply #65 on: 6 Sep 2017, 06:53 pm »
So Ive been doing some  listening and measuring. I have tweaked the crossover as the proper values are quite a bit different from the theoretical or the ones recommended using the software modelling program.
Question: How far from the wall is the recommended spacing? Thanks.

Danny Richie

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Re: Open Aire Aktiv build thread
« Reply #66 on: 6 Sep 2017, 07:15 pm »
So Ive been doing some  listening and measuring. I have tweaked the crossover as the proper values are quite a bit different from the theoretical or the ones recommended using the software modelling program.
Question: How far from the wall is the recommended spacing? Thanks.

Typically the crossover modeling software is a shot in the dark. Rarely are they close especially if using electrical parameters.

You will need to have any open baffle speaker pulled out at least 3 feet or more from the front wall.

jimbones

Re: Open Aire Aktiv build thread
« Reply #67 on: 6 Sep 2017, 11:50 pm »
OK so I am working on the XO and very interesting, I am using a 2 way 12db/oct and the system measures better with both drivers in phase! OK so what could I be doing wrong.




The other issue is a crappy looking impulse (tweeter only)



Danny Richie

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Re: Open Aire Aktiv build thread
« Reply #68 on: 7 Sep 2017, 08:51 pm »
I take it that is your upper section?

First of all I can tell by the impulse response that you are way too close. Back off to 39". Then set the start time on the impulse response to about 2.75ms and stop it at 6.75ms. That will give you a good clean time window of 4ms without room related reflections. And be sure that the speaker is not sitting close to a side wall for the measurement. And start off with the response on the tweeter axis.

When looking at a 1 meter gated time window you can crop everything below 200Hz because you really won't be measuring or catching anything below that.

And with that type of crossover they may very well measure better with both drivers in phase.

Shoot the mid individually and tweeter individually then overlay the response of the two together. That will tell you more.

And to see how well they are in phase, be sure to check vertical off axis responses. I stay with the 1 watt/1 meter reference and than move the mic up 4" per measurement.

jimbones

Re: Open Aire Aktiv build thread
« Reply #69 on: 8 Sep 2017, 12:41 pm »
I use OmniMic V2 so I will have to see if I can set start-end on gating. I know i can set end but not sure if I can gate the start.

Interesting, I did some more measurements of the Tops and the measured dipole peak and the results of a sim using Edge came out almost exactly the same. I like when that happens (as you can tell I am a newbie :) )
So I have the first dipole peak at about 450/500 hz I need to tamp down about 6 db. I used an online calculator for a RLC notch. got my values 68uf,8  ohm, 1.5mh.  Havent tried it yet but I assume this get installed after the XO in series with the Mid. Anyone have experience/luck with this?

Danny Richie

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Re: Open Aire Aktiv build thread
« Reply #70 on: 8 Sep 2017, 05:34 pm »
I use OmniMic V2 so I will have to see if I can set start-end on gating. I know i can set end but not sure if I can gate the start.

Interesting, I did some more measurements of the Tops and the measured dipole peak and the results of a sim using Edge came out almost exactly the same. I like when that happens (as you can tell I am a newbie :) )
So I have the first dipole peak at about 450/500 hz I need to tamp down about 6 db. I used an online calculator for a RLC notch. got my values 68uf,8  ohm, 1.5mh.  Havent tried it yet but I assume this get installed after the XO in series with the Mid. Anyone have experience/luck with this?

You can adjust or shift the peak with the lengths of the side wings. This is why I do so much measuring and testing of the side wing lengths. Ideally you can create a flat response with no need for notch filters.

jimbones

Re: Open Aire Aktiv build thread
« Reply #71 on: 8 Sep 2017, 10:09 pm »
Danny, I modeled it to shift the peak, but keep in mind the trade off is I also raise my cutoff frequency so it doesn't meet the woofers. Thats why the higher cutoff frequency for the woofer was critical in this particular application. Unless I go with a larger driver but then its more cabinet work  :duh:.

Danny Richie

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Re: Open Aire Aktiv build thread
« Reply #72 on: 11 Sep 2017, 02:41 pm »
A longer side wing should shift the peak further down and help them reach the lower woofers.

jimbones

Re: Open Aire Aktiv build thread
« Reply #73 on: 12 Sep 2017, 12:09 am »
OK so rather than mess with my current physical build and XO i decided to insert my minidsp into the line and play with that. Settings are as follows:150hz +2db Q=1.6 (This improves integration with the H Frame)
450hz -3db Q=2.8 (removes peakiness in the Mid) Sounds better.




Ignore hump in the low bass around 25hz. I fixed it, Ill post a new Fr.

Now I will spend some time listening to it and fine tuning. I am not used to leaving the minidsp in the loop so I don't know how "pure" sounding it is. But it does smooth out the Fr. Thanks ALL

EDIT: Forgot to mention XO HP is 90hz for the toppers 24db/oct

Danny Richie

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Re: Open Aire Aktiv build thread
« Reply #74 on: 12 Sep 2017, 04:01 pm »
Now I will spend some time listening to it and fine tuning. I am not used to leaving the minidsp in the loop so I don't know how "pure" sounding it is. But it does smooth out the Fr. Thanks ALL

My experience is that it will suck a lot of the life out of the music. The sound stage will flatten out. Depth goes away. Detail is lost. And it can be a bit harsh.

If you can take care of the response issue passively and use a good quality DAC instead then things should improve significantly.

jimbones

Re: Open Aire Aktiv build thread
« Reply #75 on: 12 Sep 2017, 04:48 pm »
Danny, my expectations match your findings, I will need to spend more time listening to it. My other equipment is more than decent (at least in my eyes) Modwright electronics, VPI  Classic 2 table, MicroBenz cart, Burson Conductor Dac, Wywires, Emotiva transport, etc.