S.E.X. + Paramounts + Lambda Unitys and TD15Xs

[keto]

Okay, I've really got to improve my source!

[xcortes]

Could you tell us your crossover points, slopes and implementation?

You're using the Paramounts on the Lambda's and the Sex above, right?

Yes, you do need a better source. The BH Dac will be fantastic for you.

[Grainger49]

Very cool!  You know you have big speakers when they need casters under them.

You really need a turntable!

We should have a sub folder here called Member's Systems.

[keto]

As 3-ways, they have a 2nd-order LP on the woofers @ 300hz, a 1st-order 300-1200hz bandbass on the mids (plus acoustic roll-offs), and a kind of complex time-alignment and CD-compensating HP @ 1200hz for the B&C DE-25s. Earphone-out (ouch) of the Macbook feeds a Marchand 2nd/1st-order XM46 @ 300hz, 300B Paramounts below and S.E.X. above. I've inverted phase on the woofers, since the 300hz XO is (very) approximately 2nd/2nd-order, acoustically. The bass bins used about 5 sheets of 3/4" material each, have an internal volume of about 12 ft3 and are tuned to 20hz with a 14"-long 8"-dia port. At first I regretted having designed such an over-damped box with so much LF extension, the latter because when I was running test tones the only apparent activity below 30hz seemed to be threatening all the windows in my apartment building. Well, the SET's low damping factor compensates (perfectly, on paper) in the bass and sounds great, and with music playing the big windows are actually NOT in danger.

[xcortes]

Grainger, I agree: Keto needs a turntable and it would be great to have a section to post and describe our systems.

Keto: so you're horn loaded from 300hz up. And not only that but also time aligned and with a single point source. It should be awesome. Come to think of it you should invite the DF gang one day. I can bring a Walkman if you're still using that Mac.

And it looks like a fantastic platform to build on with those cool tube crossovers you're building.

Can you try different compression drivers on the unitys?

[keto]

Yeah, I'll have to have the gang over. You guys listen to stuff OTT loud, ya know?

We should spin some Gilberto Santa Rosa to stay in the good graces of my Cuban neighbors.

Tom Danley recommends the BMS4550 now for his Synergy designs and I have a pair on hand -- once I get the active XO sorted out, I'll ask him about rolling those in.

I ran the test video from the Berlin Philharmonic Digital Hall site and my internet hook-up works fine on their lower-rez video option. Would the BH DAC help with such streaming audio? How would I hook that up?

[keto]

Woohoo! Less is more, this time.

The system is now reduced to a 300hz 2nd/1st order Marchand XM46, stock S.E.X. amp feeding the mids and tweets (in the pic are all the elements of the tweeter's passive speaker-level filter) and stock Paramounts on the bass bins (with their polarity reversed).

Room for improvement? Sure! But this is the best its sounded so far.

After the 1st order 300hz high-pass, the only "filter" on the mids is a 10-ohms padding resistor (7.8dB) -- and its still a little heavy in the mids. I'm guessing there's a 9dB difference between mids and tweeter, which would line up with the anecdotal 97dB and 106dB efficiency figures I remember being mentioned, years ago.

The mids are a quartet of 8 ohms drivers in parallel, so on my next S.E.X. build, I'll use the 6EM7 (which has a lower Rp than the 6DN7) and "pretend" the output autoformer is 4K:2 instead of the real 8K:4

Whew!