just investigating some claims... 
Thursday, February 14, 2019, 21:34
Posted by Anders
I just wanted to understand if I can see the similarity between a ROAR design, simplified description (2. below), and a claim made that it is similar to what is popularly referenced as a "bass cannon", the closest reference to this I could find is the Bose wave canon, see simplified description (3.) below.

I'm sorry to say I cant really see the similarities between them, but it should be said that I may have gotten something wrong here in the case of the bass canon reference, and I'm willing to change my mind if a sufficient explanation should arise.

For reference I also put in a traditional Tapped Pipe (1.) in order to try and explain how this forms one part of the ROAR design, I also attempted to describe the bose acoustimass cannon (4.), what I believe to be a Helmholtz coupled version of (3.)

Again, I may very well be wrong here, it's just a fun exercise, not a thesis, so no claims from my side as to the validity of this :)
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ROAR15 at home 
Thursday, October 25, 2018, 16:54
Posted by Anders
Just a quick post of what is going on :)

RTA low level pink noise at the mouth LPF 500Hz (no additional signal processing):

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the old and the new 
Sunday, September 9, 2018, 19:25
Posted by Anders
I figured that it was time to modernize my transducer inventory and seeing as I recently sold my Precision Devices pdn.2450's I thought I'd scale down the size a bit in the process.


That's right, it's a pair of B&C 15SW115.

Just to give an idea of just how tiny these 15SW115 really are...

And that's it, my pdn.2450's waiting to be picked up and the new small 15SW115 taking their place.

The enclosures intended for the 15SW115's are currently being manufactured by a local company, they should be ready for pickup in early November.

Right nOw I cAnnot Reveal what they are (15) ;)

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hornloaded linsource thoughts 
Monday, July 30, 2018, 08:43
Posted by Anders
What would happen if you where to hornload a linesource? this is the question that's on everybody's mind these days right, or maybe it's just me.

On the surface this seems simple enough, but when considering the inherit dispersion pattern of a linesource (wide horizontal, narrow vertical) and the way the hornloading is implemented (in this case) it becomes a bit more interesting.

What type of hornloading would the middle four drivers see as they are free in the vertical, there are no walls to guide the sound, but since this is a linesource would the driver coupling still dictate this?

Adding to that, the hornloading is frequency dependent, meaning the the highest frequencies will be less influenced by the horn, but is this still true in the case of a linesource?

In short, will the hornloading be varying gradually but symmetrically along the vertical length of the line source?

I guess I'd better turn to the forums with this one, and I don't believe it is all that easily simulated, I hope to get some answers to this, as this would be a nice way to boost the FCAM123.
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ROAR12 testing 
Wednesday, January 10, 2018, 21:48
Posted by Anders
We managed to arrange a quick test and evaluation of the ROAR12 at a local sound contractor, the test was successful and gave us both the opportunity to measure and listen together with professionals.

We got a Digam Powersoft K10 to power the ROAR 12, processing was handled by my own trusty old DBX Driverack 260.

The Top system used for comparison came from Prophon, really nice tops, the warehouse we resided in was 150m2 and the ROAR12 was positioned ~4m from from any wall (as closest distance).

Measurement at 1m was conducted without any processing, i.e. no equalization or filtering before amp.

Raw sweep capture using REW and Umic.

(ripple in the response shows influences from room acoustics).



Same conditions but with EQ applied, maximum gain at 31Hz was +8dB, at 40 +6dB, 60 +3dB, 70 +1.5dB, note that the response raise is almost 1:1.

This was interesting as the lower tuning knee acc. to simulations is approx. 45Hz, below which EQ'n should not go 1:1 with the response, but it does, this means the design loads the driver far lower then we expected.

(ripple in the response shows influences from room acoustics).

The maximum power we tested in this case was ~1kW without any HP filtering, LPF was set at 121Hz 48dB/Oct LR, the character was not noticeably changed up to the stated power levels and the driver maximum excursion was estimated to +/- 5mm, xmax for the 12PS100 is 8mm.

The design seems to couple the driver very well, and the smell of heated voice coil was at times noticeable (not unusual with a fresh driver), the design does indeed seem limit more thermally then mechanically (excursion).

A very interesting test and I'm very pleased with the results, the professionals present was indeed impressed with the design, a lot of questions, nodding, and positive statements.

Smoothed response measurements will be added shortly.
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