willbewill's OB Line Arrays

willbewill · « **on:** 19 Jul 2009, 03:29 pm »

The project starts

A pic of the first one - not wired yet

No crossover at all, they are wired in 4 lots of parallel which are then wired in series - brings them roughly back to impedance of one unit.
wired the first unit - and tested it as one channel in a stereo setup.

Sounds beautiful, pulls the open baffle trick of disappearing, surprised just how good the bass is (response of these drivers is 45hz-20khz), detailed and low.

Only problem is that on one of my 'test' tracks (on a Naim audio cd) a couple of the drivers are distorting...looks like I'll need to buy a few more spares

Original sensitivity is around 88-90db but I think the completed unit is about 95-96db, impedance measures 4 ohms, I'm driving it with a Trends Audio TA-10.1 class-T stereo amplifier.

They are Wharfedale units supposedly as used in Modus Cube speakers but do not say Wharfdale on them - sticker says:

103.84
49101 40311/02
6Ω 3945

Here's the inspiration for what I'm doing:

http://www.geocities.com/dmitrynizh/labaffles.htm

Finished the other speaker.

Initial impressions:

Huge sound stage that has height as well as width and depth.
A large 'sweet area' instead of a 'sweet spot'.
Great detail.
Vocals are lifelike.
Acoustic instruments appear accurate.
Bass goes surprisingly low - can be felt in stomach.
They go pretty loud even with Trends Audio T amp.
It's not like listening to a pair of speakers - no 'point source'.

I'm sure they are going to 'loosen up' and get even better.

've been listening - using a 70s Sony receiver (great sound), these speakers really appreciate the extra power. The T-amps are beautifully detailed but very 'thin' sounding compared to a higher wattage item with these stacks.

Drums are phenomenal when the system is cranked up with Blue Neon as the source using a Shure M95 cartridge with a Jico HE stylus (much better than M95HE

But the treble is very limited and I am sure is really affected by the design of the arrays - I had to turn the treble control on the Sony right up to make it listenable - so it looks like I'll be fitting some tweeters.

Edit:

It's now later and I have fitted a pair of tweeters (complete with crossovers) from Mordaunt Short Festivals - arrays are still running fullrange with only the tweeters using crossover.

What a difference

Latest setup:

Added a Yamaha YST-SW200 subwoofer - now the speaker system sounds really good. Drums are amazing, vocals very lifelike and soundstage huge

Now being used with a Pair of 10w Kerr McCosh Valve Monoblocks

Mr Content · « **Reply #1 on:** 25 Jul 2009, 11:58 pm »

Wow, very nice. is this your first OB. I have wanted to build a floor to ceiling line array for some time. What dia. are the drivers

Mr C

willbewill · « **Reply #2 on:** 27 Jul 2009, 06:19 pm »

Yes my first OBs. 4 inch drivers.

Telstar · « **Reply #3 on:** 27 Jul 2009, 10:33 pm »

Did you find any advantage using oblique wings rather than 90? ones? Besides aesthetic.
I remember to have read some stuff on John K site.

willbewill · « **Reply #4 on:** 28 Jul 2009, 07:06 pm »

Quote from: Telstar on 27 Jul 2009, 10:33 pm

Did you find any advantage using oblique wings rather than 90? ones? Besides aesthetic.
I remember to have read some stuff on John K site.

This was the inspiration for the hinged side panels:
http://www.geocities.com/dmitrynizh/labaffles.htm

Quote

...the front baffle must be narrow to avoid degradation of imaging and independently of that the sides should be facing slightly rear, not exactly sideways, to avoid "flat and shallow" soundstage.

These two factors influenced by current design featuring very narrow tall and concave front baffles and side panels opened backwards at 110...140 degrees. The angle can be adjusted as the side panels are on hinges.

Narrow front for better imaging, sides angled towards rear for deeper soundstage.