My project is simple, no active EQ or compensation, just a large sealed box system with a lowish overall system 'Q' approx 0.5 - 0.6 about 200 litres, a fairly rigid brief though.

I have built several of these before but not above 8" based and around 50 - 70 litres.

I have now broadened this project brief to consider other drivers and have found two 13" units from SB acoustics which look ideal for this project, one providing an ideal system Q ~ 0.5 in a box of 150 litres.

This 13" model will provide near 20Hz extension in room -3dbs (-6dbs @ 30Hz raw response) with some rear wall boundary assistance, I could EQ to get deeper but from plenty of experiments I have made from my teenage years to about 5 years ago I have never been truly happy with any equalised alignments I have tried, and I have tried about a dozen.

The 15" SB acoustics driver is the best I have found thus far but one of the other models from SB acoustics and provides very close to 20 Hz -3dbs with higher output but in 230 litres.

It appears that excepting the audiotech drivers which can be customised at a price but alas are priced outside of this brief; that there are few suitable 15" drivers with the raw parameters that match my design brief around.

This thread was just asking simply has anyone had experience or knows of a suitable 15" driver suitable for a box around 200 litres and so mounted in such an enclosure with a resultant system Q approx 0.5 - 0.6

Edited by user 03 November 2013 15:06:54(UTC)  | Reason: Not specified

Yes the DBL used an ATC unit IIRC they are good but as you say not easy to get hold of.

Considered Isobaric loading as I have 4 Focal 13V7511 drivers not used so that is a possibility.

Fs only goes down by rt2 as the suspension stiffness becomes completely negligible compared with the cabinet stiffness. You'll get somewhere in between nothing at all (free air or infinite cabinet) and rt2 (infinitely compliant suspension).

2 x 10" Seas L26RFX/P units can provide 20Hz in room in around 200 litres, this is a large enclosure but would likely time quite well.

With a load tolerant amp and suitable backup I have decided on three of the Seas 10" drivers some vol stuffing in a 250 litre sealed enclosure for a serious project for 14.

I have revelator mids and a few tweeters to play with as well; Birch or HDF is the next question?

Perhaps I'll write up the iterative process I have gone through in arriving at where I am and the design process as it is progressed next year

One large low 'Q' sealed enclosure is envisaged the drivers that will likely be used for my project are totally unsuitable for OB use.

Great drivers for OB use include a model from Eminence

I was only thinking of the mid and top to be OB for this project

Like it was an idea I was going to try on a future project but could easily adapt this one to suit series parallel means I can retain an 'easy' load; the Seas units are amenable to this meaning I could create a really solid enclosure with this arrangement together with some fancy coupling and system/cabinet wall tunability as well.

Could play with theoretical modelling to see how varying mass load will affect other parameters before I commit to actual mass loading requirements.

14 could be a fun year

I remembered this from somewhere. Look how the idea develops rather than specifics.

cyclop

That looks similar to the construction method recommended by Ken and others. Two layers of ply with a lossy layer. But having it prebuilt will make everything about 100 times easier.

Do you know what thickness each layer is?