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Electron 25th January 2010 11:32 AM

The future for driver data
 
Is there frequency responce measruements available for Alpair 12, something like to 0, 30 and 60 degree angels?

What about distortion and stored energy?

Hi Electron and guys,
I've started this thread and migrated the posts from Alpair 12's thread. Like Human Hearing, its worth a devoted thread. Appreciate this issue has been done on other threads, but a re-visit could be worth doing.

Must dash to the studio!

Cheers

Mark.

markaudio 26th January 2010 05:28 AM

Hi Electron,
I've had no time to do the off-axis, sorry. I'll have some spare time during Chinese New Year (I hope).

You'll have to more specific by specifying the measurement methodology and data outcome for distortion and stored energy.

Mark.

planet10 26th January 2010 06:56 AM

1 Attachment(s)
Quote:

Originally Posted by Electron (Post 2060630)
Is there frequency responce measruements available for Alpair 12, something like to 0, 30 and 60 degree angels?

What about distortion and stored energy?

I've been encouraging Mark to get Floyd Toole's book. The goal being to get Mark to start doing the measures that correlate with how things sound.

If we assume that since it is a single FR, that a vertical set is the same as a horizontal set, 0-90 degrees at 10 degree intervals would be of interest.

Geddes has shown that THD distortion measures as they are currently taken have no correlation to sonics (Toole pretty much agrees with him) i'm not concerned with that, but stored energy is important to my mind. I'd like to see more sophisticated tests than the simple waterfall (which usually is shown with far to limited resolution -- and usually with a hard to interpret "time" scale. Z axis sould be in periods -- Kirchner's ATB is one of the few i've seen that does it right)

dave

Electron 26th January 2010 06:07 PM

I think the frequency responce measurements would be without so heavy smoothing. They look like 1/3 octave filthered. Could you use 1/24 ocatave smoothing. I know it looks much better as they are now but to get better understanding about quality there need to be more details in response curve..

Intermodulation distortion is what I ment by distortion measurement.

markaudio 26th January 2010 09:43 PM

Quote:

Originally Posted by Electron (Post 2062449)
I think the frequency responce measurements would be without so heavy smoothing. They look like 1/3 octave filthered. Could you use 1/24 ocatave smoothing. I know it looks much better as they are now but to get better understanding about quality there need to be more details in response curve..

Hi Electron,
I've got allot of sympathy with your position. I publish RAW data on the other threads for prototype and test drivers in this section of the forum. When I published raw data for my first batches of drivers, I was panned by some of the guys who didn't know the difference between RAW and smoothed. Their public comments caused allot of problems, I was forced to smooth in order to stay in business.

If you can persuade the rest of the industry to agree on a data presentation standard and educate those members with less knowledge, then I'm with you 100% of the way and will gladly publish RAW data for all current drivers.

Thanks

Mark.

markaudio 26th January 2010 10:03 PM

Quote:

Originally Posted by planet10 (Post 2061764)
I've been encouraging Mark to get Floyd Toole's book. The goal being to get Mark to start doing the measures that correlate with how things sound. f we assume that since it is a single FR, that a vertical set is the same as a horizontal set, 0-90 degrees at 10 degree intervals would be of interest.
Geddes has shown that THD distortion measures as they are currently taken have no correlation to sonics (Toole pretty much agrees with him) i'm not concerned with that, but stored energy is important to my mind. I'd like to see more sophisticated tests than the simple waterfall (which usually is shown with far to limited resolution -- and usually with a hard to interpret "time" scale. Z axis sould be in periods -- Kirchner's ATB is one of the few i've seen that does it right)
dave

Hi Dave,
With you on this. Time and resources are the challenges. I'm averaging 13 hour working days, this includes Saturday. I love the work so the passion keeps me moving. I'm hoping for a better year financially so I can invest in new measurement technology.

As said to Electron, if only there was an agreed test and data presentation standard throughout the whole speaker world, life would be so much better. From some makers perspective, the more data they publish, the more it gets picked apart (partly explains why Feastrex don't publish). This is OK if the guys doing the picking have sufficient knowledge to accurately interpret the data.

I personally want to gradually migrate to publish more sets of data. This includes no smoothing in the case of frequency. But it carries commercial risks as I've found to my cost in earlier times.

I'm always glad of your encouragement, you devote allot of time and passion to the hobby so many thanks for your contributions.

Cheers

Mark.

markaudio 26th January 2010 10:21 PM

Hi guys,
Ummmmph.....maybe a new thread is worth doing on the data issue. The Human Hearing thread went well. I'll try to arrange later today.

Cheers

Mark.

planet10 26th January 2010 10:41 PM

Quote:

Originally Posted by markaudio (Post 2062701)

if only there was an agreed test and data presentation standard throughout the whole speaker world, life would be so much better.

I think that part of the purpose of Floyd Toole's book was to propose just such a standard. Certainly the full set of measures is beyond most diyers. Some investigation of a useful subset needed there. With a FR driver things get simplier.

And he has research which correlates sonics to the measures.

dave

Electron 22nd February 2010 12:22 PM

Mark, have you had time to do any measurements?

My project is in hold until there is more data.:(

markaudio 22nd February 2010 12:33 PM

Hi Electron,
Remind me what specific data you\'re after and how you need to use it in your project.

Mark.


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