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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ROAR12 in the livingroom... 
Sunday, August 27, 2017, 18:54
Posted by Anders
Johannes came by and dropped of the ROAR12 for me to have a listen to, a really nice experience, it quickly became clear though that the ROAR 12 is not suited for indoor duty, at all, but again that was never the intended use.

Given a corner placement in this room 30z was not a problem to reach, with a very tactile character, even at very low levels you feel it everywhere, it's not a very neighbor friendly device at all.

Crossed over at 153Hz (24dB/Oct LR) it blended nicely with the FCAM's even though it took some crossover and gain tuning to get it to not dominate the reproduction, it is indeed very efficient.

Bare in mind that these are indoor low level usage impressions and the room contributes a lot, both good and bad.

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ROAR prototype build 
Tuesday, March 14, 2017, 17:44
Posted by Anders
Prototype build pictures courtesy of Johannes Rodin who also designed and built it, this is a 2x12" TPQWR (or 6:th order series tuned bandpass) loaded with Beyma 12P80Nd :

The result spurred us to get the ROAR designs finalized and published, although still purely theoretical they all follow the same basic premise and theory as the prototype shown above but with a lot more iterations and careful tuning to get the best result out of each driver size.
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ROAR family overview 
Thursday, March 2, 2017, 18:02
Posted by Anders

The ROAR designs are all made up of a constant area tapped system coupled with a quarter wave resonator, the TPQWR abbreviation aims to describe this as Tapped Pipe (constant area segment) + Quarter Wave Resonator (another constant area segment).

In theory this results in the passband range of a tapped constant area system (wider then its corresponding TH) with a in passband efficiency grater then that of their corresponding TH equivalent.

Regarding the naming, putting together a name based on the design principles involved proved to be an impossible task, so we opted for Johannes Rodin's surname initials and something that described the prototype build characteristics.... ROAR! :)

ROAR15 and ROAR18 is IPAL compatible!

With only minor adjustments to the original design the ROAR15 is 18IPAL compatible, as is ROAR18 with the 21IPAL, according to simulations, the adjustments required is limited to adapting the driver cut out, adding some additional rear panel bracing and in the case of ROAR15 an upward offset of the mouth brace by approx. 20mm.

Please note that the only ROAR design that has been built so far is the ROAR12, and it shows a lot of promise, you can find pictures in the ROAR12 link below, courtesy of Johannes Rodin.

Links to ROAR design proposals intended for professional use :

370x550x750mm (WxHxD)
152,6dm3 external volume

450x640x800mm (WxHxD)
230,4dm3 external volume

580x820x820mm (WxHxD)
390dm3 external volume

600x960x960mm (WxHxD)
553dm3 external volume

Prototype build pictures :

ROAR prototype build

size comparioson :

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