Any idea what the lossy visco-elastic layer is here?

Posts have not altered in width on my iPad

Or PM's much loved PMC IB2s?

Great ideas, really looking forward to your developments........nice to see how things progress (hint hint)

Speaking of looks, a lot of what you remember is based on the drive units and surrounds with many speakers being simple rectilinear shapes. The NS1000 having their units in a b shape layout but the NS1000x and 10000 had their drive units in a line. However what I really remember is the unusual drive units and the level controls. And with 3 units in a row you gain cabinet space without having to make a deep box. The limiting factor here is your cabinet making skills

About to start construction work on one design, I will not say too much about that design at the moment

Edited by user 23 June 2014 22:28:24(UTC)  | Reason: Not specified

If I were a betting man, I would bet that you will go for option 1.

Presumably with option 2 you would need to keep the xover freq well away from the vocal region - is this a problem?

Hi,
As an update to my active transmission line speakers - i based it on the Hifi News Richard MacDonald design - but then, they are all very similar. I used the Leonard transmission line software to model.

I did not use a tapered line, but with the relevant wadding and moving the bass driver down the line, the 2nd mode can be reduced to create a near flat response. The -3dB point is at 28Hz.

I am using a three way design - Volt B2549 Bass, SB Acoustics SB17NBAC35 Mid Woofer (240Hz to 2.4kHz), SB Acoustics Satori TW29RN Tweeter.

Had the cabinet CNC work completed, and i am currently adding the foam to the panels before construction. I sealed the MDF with primer before adding the foam. I am using a combination of 40mm egg crate acoustic foam and 12mm flat acoustic foam.

The internal design is not very good for construction as a business - as it will take too long for each speaker - so this is definitely a hobby only project.

I have completed the design for the active filtering - 4th order, using op-amps as opposed to DSP. I have completed my own amplifier design - which is voltage feedback, but may use a current feedback design in the future. I am using Neutrik SpeakON connectors, so this can be a straight amplifier swap.

Once i have completed the construction for one half (before i place the other side panel) i will upload some photos.

One of the pains is cutting the foam. Although i used a scalpel - there are small foam bits everywhere - so had a lot of work to clear those up, and the finish is rather coarse.

I was also surprised at the total cost for the foam - £120 total - and just about enough. Still have to buy the wadding.

Regards,
Shadders.

My own project has evolved somewhat to a modular approach with separate decoupled mod and treble enclosures which will be positionable to gain some time alignment.

Sealed box for the bass.

DM :)

12" Bass drivers are under consideration, just finding the right units. 15" or even 18" units are not an issue either as I am happy to house necessary sealed enclosures of Q=0.5 - 0.6)

I am still looking at using the 8" Seas FR unit with a tweeter in waveguide to cover the upper range, why not a pair of the 8" units per side either side of the tweeter/waveguide?

These 8" units look excellent as a upper bass / mid firstly Seas CA22RNY

Or from Jantzen a custom Seas JA 8008

Bass units remain the problem. At low cost but they have a decent set of parameters are these from BK Electronics AD 12-300? they model well in a Q=0.5 enclosure and could be used in multiples.

you mention 9dB gain at the lowest desired frequency but it rarely hits that spot
due to losses from the finite rigidity of the room boundaries
Colloms