[OZZIOZZI]

Has anyone tried using one or more small distributed mode loudspeakers fullrange or limited to ~100-200 Hz upwards plus helper bass driver on OB? Ie run DML panels fullrange plus helper bass? Or Crossed over active or passive, biamped or not. Any comments would be appreciated. Does putting these panels IN a larger baffle improve their bass performance. I am doing experiments at present, but wondered if anyone else has tried this approach. Think Goebels speakers for what I mean.

Ozziozzi

[Bendingwave]

Are you talking about a Sub/Sat system? If so yes I have as I had the small panels crossed over at 200hz while the sub handled everything below 200hz. Oh and I am talking about a DML Subwoofer although I have used the standard traditional cone type subs as well but IMO a DML sub blends better with the DML sat. panels.

[OZZIOZZI]

Hi Bendingwave, yes I am talking about a sub/sat system although with stereo subs.

Crossover like MJKs OB Eminence alpha plus FE103

I planned to use cone woofers, but I am interested in what you used for  sub DML panel, XO details etc as the two DML panels should be easier to "blend" at the XO point having similar sensitivies and sound fields. What size and material sub panels did you use and how did you drive them? I have Dayton 24W exciters with the four metal mounting tabs on the magnet side.

Any info would be appreciated as most DML fans seem determined to achieve a fullrange panel rather than what you described. I am just trying to avoid bass panels the size of fridges.
Thanks for your reply. Sorry I took so long to answer. I have been ill and then off air for awhile.

Cheers

Ozziozzi

[Bendingwave]

This is what I used for my sub panel its very simple.

1. DAEX30HESF-4 Exciter 40watts rms.....The DAEX25 is good also as it has the mounts to mount it on a spline/brace.

2. Panel material is Ultimate grade EPS 1inch think and 16inchesX24inches not by choice but by what was available from that company.

3. Driven by a 50 watt sub plate amp with variable crossover.

4. Exciter needs to be mounted to a spline attached to a brace to hold the exciter as well as the panel in place for high excursion out puts.

All my DML designs mimic Bertagni speakers including the sub but if you are not familiar with Bertagni speakers you may get a better idea of what I am talking about with BMR technologies designs which is basically the same type of design as Bertagni speakers.

[OZZIOZZI]

Hi Bendingwave, I am familiar with the various Bertagni models from pictures on the web, but have never heard them live. I dont think they got out to Australia in quantity 
I wonder if you could reproduce their design ideas by making a mold and filling it with self-expanding foam? Just a thought. BES seem to follow same principles as NXT with their dampening (wax or silicone?) and ridges/valleys around edges of panels which I suspect act like a flexible surround that is also damped critically.
I have always believed that the NXT design software would make life easier for DIY  panel makers providing they could get or measure the parameters of the panel material such as mass/unit area, stiffness, bending moments. All these things are available if you purchase high tech materials as they are important to manufacturers. The DIYer relies a lot on guesswork and experimentation, which can take forever 
By ultimate grade EPS do you mean the blueboard type of material that is much harder to dent than normal EPS? I have seen something like that in a hobby shop and hardware store where it is sold for making wings or fuselage for gliders. It's very stiff, light and stronger with a finer "grain" than the white EPS.

Do you bother rounding corners and edges and how do you support it at the edges. A few pictures would be
great. I will look around for the better EPS. While I wait for your reply.

Thanks for the info so far.
Is this what you mean for EPS?



Ozziozzi

[Bendingwave]

Hey OZZ.... that does sound like a possibility as I believe Bertagni used a type of mold to make his EPS panels from.


It took me 2 and a half years of experimenting with my designs anywhere from 1- 5 days a week at times it was very frustrating but I finally perfected the sound to where I am satisfied.

No, Blue board is XPS(Extruded Polystyrene), usually the colored boards are XPS while the white boards are usually EPS (Expanded Polystyrene)....I do not like the sound of XPS and prefer the warmer tones of EPS.

With EPS the place I buy it from has 5 different grades.
Low density
Standard density
High density
Extra high density
Ultra high density

I use either the Extra or the Ultra high density as those two have the best accuracy....the lower softer densities grades muddy the sound.

Yes I round the edges....the edges of my panel are supported by a 3/4 inch foam by frost king attaching the panel to the frame.

I have posted some links in the other NXT rubbish thread showing the design of Bertagni speakers as my panels mimic them a lot so reading those links can show you a glimpse of how my panels are designed.

[OZZIOZZI]

Hi BW my local suppier of XPS sells three grades,
SL =  ordinary insulation type, 13 kg/ cubic metre
M/HD  = 19kg/ cubic metre
H = = 24kg/cubic metre

I have inquired about availability, sizes etc

A$8.10 for 600 X 1200mm sheet 25mm thick, only other thickness in H is 15mm
This grade is normally used for XPS signage, cutout figures etc.

For non-metric countries  that translates to:
2ft X 4ft  X 1" thick  24kg/m^3  = 1.5 pound/ft^3  $1.10 per cut is good value too if you want nice clean cuts.

Did your supplier have any figures for density of the XPS that you used. I think 15mm would be too thin?
I like the look of their hot-wire cutter too. Must make one !!!!! Someone told me that piano wire or steel guitar strings are good for that job.

Ozziozzi

[Bendingwave]

Hey OZZ....I would go with the higher grades as the stiffer harder grades sound more accurate to me....2X4ftX1inch is a good size to experiment on with the DAEX25he exciter.......15mm is alright to use also that is around 1/2inch.

The place where I order my EPS panels from is on Ebay, he is called Mr.Polystyrene.....the only down fall is they only come in one set size, only the thickness and grades are adjustable but the size is 600X400.


http://www.ebay.co.uk/itm/EXPANDED-POLYSTYRENE-SHEETS-FOAM-PACKING-VARIOUS-THICKNESS-AND-GRADES/201604023608?_trksid=p2047675.c100011.m1850&_trkparms=aid%3D222007%26algo%3DSIC.MBE%26ao%3D1%26asc%3D20140107083358%26meid%3D955371309a124fbaa587e739dbc51540%26pid%3D100011%26rk%3D1%26rkt%3D6%26mehot%3Dpp%26sd%3D200991844997