Subs come to Quad ESL

Simon visited last weekend with a pile of experimental equipment in tow.
A spare pair of Audiosmile 3/6 prototype cabinets fited with a new baffle and very high performance 10" subwoofer driver. Sealed cabinet.

We also had the Audiosmile version of the DCX digital crossover and amidst the rapidly growing pile of beer bottles began experimenting with integrating the subs with the 63s.
The subs were positioned immediately behind each 63 directly onto the floor and close to the side wall, firing through the ESL63 open stands.

After some initial measurements Simon got them dialled in pretty quickly with impressive results. Quads rolling off at 80hz 24db/oct and the subs rolling in at 60hz, also 24db/oct. Output to the 63s was delayed to align with the subs.
A little PEQ also to tame the dominant room mode at a little above 40hz.

Got to say it works far better than I would have imagined.
So many tales of difficulties marrying 'slow' box subs with 'fast' open statics but I can honestly say the join here felt seamless. You just get the fundamental sound of a Quad ESL but with the kick and extension of a really good MC box loaded system.
The key is undoubtedly due to three things. Good phase alignment, rolling in steep and low, and relieving the ESL of dealing with <80hz signal which is where input transformer limitations start coming into play.

ESL63s are pretty insensitive at anything between 83-85dB depending on who's measurement criteria you use. The subs naturally have a good 3-4dB advantage, which in combination with the gain from boundary positioning allowed for some EQ at the very bottom without undue stress on the amplifier. We actually got -3dB at 20hz and the 405-2 on the subs has never run cooler! - it ran at around idling temperature most of the time even when cranked, a benefit of high overall impedance from a sealed cabinet sub operating over a limited range.

Some pics. I'll take some in room plots in a few days and add them:



IMG_0784 by trebor1966, on Flickr


IMG_0783 by trebor1966, on Flickr


IMG_0782 by trebor1966, on Flickr


IMG_0778 by trebor1966, on Flickr

 

How are you getting on Rob, still using it this way or been seduced by the lure of vintage dials again?

 

I have both on the shelf - it's easy just to switch over

I'm in the middle of fixing up so much stuff at the moment that there are too many changes. In the run up to christmas I'll settle things down and just do some relaxed listening.

 

Yeah I know that feeling. Once you start working with audio kit your system never remains static. A few days ago I had a ReVox CD player in my system

 

Never played with one but those look very nice.
Are they as solidly built as they look?

 

Not super solid, plastic end caps and draw, folded steel chassis. Better than budget players today but not like the fully cast case of a Cyrus. Nice TDA1541 chip inside and not without output filtering!