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Old 23rd August 2011, 03:29 AM   #521
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Just a quick note. You might want to read this post splicing nearfield to farfield, does this look right? when you do your summing of the driver and port response the port response needs to be "normalized" first

The third pic where you have set the gating to 20Hz looks very good! very little in the way of reflections! I'm wondering if you can move your whole setup to the right to get away from the railings altogether, or are you relying on them to balance the mic boom? If you can get the elevation on the mic lifting the speaker a meter or two off the deck would be even better

Tony.
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Old 27th August 2011, 11:18 AM   #522
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I've come up with this idea, maybe its old, I dont know..


Sound energy reflections are minimized by the rotating wall, made from triangular wedges as seen on video..

Rotunda - YouTube
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Old 27th August 2011, 01:58 PM   #523
Loren42 is offline Loren42  United States
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Quote:
Originally Posted by JonasKarud View Post
I've come up with this idea, maybe its old, I dont know..


Sound energy reflections are minimized by the rotating wall, made from triangular wedges as seen on video..

Rotunda - YouTube
You just reinvented the Leslie Organ.

Unfortunately, it will not help measurement.
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Old 27th August 2011, 02:29 PM   #524
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Quote:
Originally Posted by Loren42 View Post
You just reinvented the Leslie Organ.
Well, that's not a bad accomplishment!
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Old 27th August 2011, 02:37 PM   #525
Loren42 is offline Loren42  United States
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Well, that's not a bad accomplishment!
That leaves you the Farfisa organ to reinvent.
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Old 27th August 2011, 03:00 PM   #526
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Gentleman, this thread is the default users manual for using HOLMimpulse.
Let's keep it useful and uncluttered.

Thanks

Last edited by WithTarragon; 27th August 2011 at 03:00 PM. Reason: ...
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Old 27th August 2011, 03:47 PM   #527
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Quote:
Originally Posted by WithTarragon View Post
Gentleman, this thread is the default users manual for using HOLMimpulse.
Let's keep it useful and uncluttered.

Thanks
You surely must have missed it, but the device I'm taking up here is supposed to be used with HolmImpulse for counteracting room reflections!
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Old 27th August 2011, 09:39 PM   #528
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Default Tuning 4-way system for the Honda Ridgeline

I was looking for a cost effective way to tune my Audio system and I think the Holm impulse software is the ticket. I thought I would document my tuning process and maybe get some pointers from the experts along the way.

Here's my equipment list:

Deck: Alpine IDA-X305s w/ PXA-H100 (processor)
Amp: Zed Audio 6 Channel
4 way system: 1" tweeters, 3" midrange, 6.5" midbass, 10" sub

The goal is to use HolmImpulse to help w/ the following:
  1. Verify x over settings
  2. Set xover slopes
  3. Set db levels for speaker and left/right at the listening position
  4. Eq (parametric ) using PXA-H100
  5. Time alignment for speakers
I plan to do this in this specific order. See pic for equipment. The PXA-H100 is sitting on the floor for the time being.

I've taken some initial measurements. This will be my baseline.

Sub : LP 60hz
Midbass : Band passed 80 Hz & 250 hz
3" midrange: Band passed 315 Hz & 4.2 Khz
Tweeter: 4.2 Khz on up

The green curve is mid-range + tweeter, red is mid bass, and purple is the sub. The second picture is a measurement combined w/ all speakers. This is for the "right" side only.

It seems a lot folks on this forum focus on home audio, it may be interesting to see this car audio project. I've heard that car audio has its own unique challenges. I 'll post again after taking more measurements.

Any comments are greatly appreciated. My initial observations is that I may want to work on increasing the xover slopes. thx.
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Last edited by bginvestor; 27th August 2011 at 09:59 PM. Reason: typo
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Old 30th August 2011, 01:22 AM   #529
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Default Polarity check...

This is interesting... I checked my baseline plots and it appears that both left and right mid-bass channels are connected in negative polarity (if I'm interpreting the impulse time histories correctly). I'll correct this. I made sure that the sound card calibration showed the impulse in the correct positive axis.

On a different note, if I wanted to time align the various speakers (sub,midbass,mid+tweet), which signal generator is most appropriate? If using a sine sweep , I would expect speakers to respond in time differently depending on speaker "size".

My guess is the square noise. It sounds like pink noise to me and it should excite all the frequencies. What does the term "square" mean? thx.
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Old 30th August 2011, 01:33 AM   #530
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Sweep or MLS will give you the same impulse, or close enough. Yes, they well respond differently because they are filtered high and low. Even without a crossover they still roll off top and bottom. If you lock the time in Holm you'll be able to see that.
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