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Old 21st November 2010, 05:32 PM   #1451
Mark Kravchenko --- www.kravchenko-audio.com
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Default Houston I think we have a Problem

I have been recently working on a car subhorn design. The falling response is to complement the rising response in a car environment. Pretty close to the transfer function found in my vehicle.

The figures calculated for the B&C set of drivers seem to make sense as they are a baseline efficiency of 97db/m

The figures for the MCM drivers have me wondering what is going on. I have a driver with a baseline efficiency of 87db. And the resulting 1 watt SPL in Hornresp is almost the same. A horn cannot come up with 20 db of gain.

Or I'm really missing something stupidly simple.

So if it's me I'm all ears. If it is the calculations then ....

Me thinks I have found a problem.

I have a request for the Master McBean.

Is there or has there ever been a request for a rudimentary fold engine? One where we the user could manipulate a segment or so to make a horn folding a little easier.

Maybe I'm asking for two much. But no ask no get right?

Mark
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Old 21st November 2010, 07:36 PM   #1452
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Are you simulating everything in eighth space? That can account for a lot right there.
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Old 21st November 2010, 10:54 PM   #1453
bjorno is offline bjorno  Sweden
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Quote:
Originally Posted by a_rabid_monkey View Post
....That can account for a lot right there...
No, I don't think so, have a look at this:

b
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Old 22nd November 2010, 12:46 AM   #1454
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That is about normal compared to some of mine.
An AV15-H in the same sealed volume, one with a horn, one without, there is a uniform 10 to 15 db of gain.
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Old 22nd November 2010, 07:47 AM   #1455
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Hi Mark,

Quote:
Originally Posted by mwmkravchenko View Post
The figures for the MCM drivers have me wondering what is going on. I have a driver with a baseline efficiency of 87db.
Your MCM example shows two drivers connected in parallel, horn-loaded with a compression ratio of 5.03 : 1 and propagating into eighth-space via a relatively long, very low flaring rate horn - operating conditions quite different to those under which the 87dB single-driver "baseline efficiency" figure would have been obtained. The Hornresp results seem quite reasonable to me :-).

Quote:
Originally Posted by mwmkravchenko View Post
Is there or has there ever been a request for a rudimentary fold engine? One where we the user could manipulate a segment or so to make a horn folding a little easier. Maybe I'm asking for two much. But no ask no get right?
I think that in this case you might be asking just a little too much :-). Building a useful (and robust) horn fold engine would be a rather challenging task, I expect.

Kind regards,

David
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Old 24th November 2010, 03:30 AM   #1456
Mark Kravchenko --- www.kravchenko-audio.com
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Well thanks for the reply David.

Sometimes I need a bit of a look over the shoulder to check if things are all still working correctly.

I knew that was a real big ask.

But when I asked for the slider in the Horn wizard you went way above and beyond. I still thank you from the bottom of my heart for those little tools. They are my favorite part of the program.

I have been working on some recent designs. I thought that the following would be a good assurance of your programming abilities.

Measured by a colleague of mine :

The red line is the simulation the other lines are live measurements taken indoors 18 inches off of the floor swept sine wave. Not gated.

Mark
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Old 24th November 2010, 04:22 AM   #1457
tb46 is offline tb46  United States
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Default Locking Variables.

Hi David,

As Mark just brought up the Wizard :-).

Would it be possible to add an S4 slider to the Wizard for the tapped horn, or is the slider space completely taken up? Many times when I try to model a tapped horn I find a major improvement by increasing the size of S5 beyond what a standard "straight" taper would call for. Another way for that kind of functionality would be to provide a lock button (or buttons) for the S values as we have right now with the "Horn - S2 Fixed" condition window.

Come to think of it, "Lock Buttons" - or a lock function - similar to the lock function in a spreadsheet (e.g.: right click on a variable and select Lock) on all variables would greatly enhance the functionality, and possibly reduce errors, particularly if the "Lock" is transferred when hitting the Add button.

I also want to join Mark in thanking again for your effort, it is highly appreciated.

Regards,
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Old 24th November 2010, 07:31 AM   #1458
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Quote:
Originally Posted by mwmkravchenko View Post
The red line is the simulation the other lines are live measurements taken indoors 18 inches off of the floor swept sine wave.
Hi Mark,

Thanks for the thanks, and for posting the "measured vs predicted" comparison results.

Kind regards,

David
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Old 24th November 2010, 07:51 AM   #1459
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Hi Oliver,

Thanks for the thanks, to you also :-).

Quote:
Originally Posted by tb46 View Post
Would it be possible to add an S4 slider to the Wizard for the tapped horn?
So far I have managed to resist the temptation to undertake any further development of the Tapped Horn Wizard. The work required to implement enhancements such as you suggest, would be considerable indeed. I am struggling to justify the effort involved, considering the limited benefit to be gained. Nevertheless, I will take on board your comments, and keep them in mind for the future - I am not promising anything, though... :-).

Kind regards,

David
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Old 24th November 2010, 01:11 PM   #1460
tb46 is offline tb46  United States
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Hi David,

Thank you for considering. I can only begin to imagine how many man-hours you have put into this effort. Thanks.

Regards,
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