Is DEQX a game changer?

Thanks for the nice words, guys, and especially to Andrew for the kindly offer.

I'll most likely be ordering the HDP-4, together with the DEQX/Earthworks M23 calibration kit, in January or February. As a technically oriented person, I'll try to implement all of the procedures myself, at my own (slow and deliberate) pace. I suspect that will extend over at least several weeks before I either declare the profiles and settings to have been finalized, or decide that I need to take Andrew up on his kindly offer and/or utilize the DEQExpert service.

I'm planning on using the HDP-4 in place of, rather than in series with, my existing preamp (a Classe CP-60), which receives inputs from five different sources, and provides outputs to three different destinations.

My two most critical sources are CDP and phono. Pending possible revision during my listening tests, I'm planning on connecting a digital output of my Bryston CDP to the HDP-4 via AES/EBU. I'll connect the output of my phono stage (actually, the phono section of a vintage Mark Levinson ML-1 preamp, accessed via tape outs) to the HDP-4's unbalanced analog input.

For the less critical sources, I'll connect a digital output of my Squeezebox Touch (which I only use for internet radio) via Toslink. I'll connect the outputs of my vintage tuner and Tandberg cassette deck (I still have occasion now and then to play some musically and sonically excellent classical cassettes from way back when on the Connoisseur In Sync Label) to a mechanical switchbox that will select between them, with the output of the switchbox connected to the HDP-4's balanced analog input via RCA-to-XLR adapters.

I'll be connecting one of the HDP-4's three sets of outputs to my VAC power amp, one to my STAX headphone amp, and one to the cassette deck (although I can't recall the last time I ever recorded anything with it). Obviously the outputs to the Stax and the Tandberg will be configured for bypass mode.

Thanks again. Best regards,
-- Al

Don't rush to dump your preamp. The DEQX is essentially transparent, so you can use them together if you like what the preamp adds to the sound of your system.

Al,

I will stay tuned. I'm very interested in your finding as I'm sure are many here.

Not to make more work for you, but I would be very interested to understand the effects of DEQX on various speakers of various designs, in a sense as a potential objective way to measure speaker distortion, perhaps on some relative scale.

Thanks for your further comments, gentlemen.

Psag, even if I do end up removing the Classe CP-60 from the system, I don't envision selling it in the foreseeable future. It's much too good a performer, IMO, to be selling it for what I suspect it would bring. (I paid $1350 for it about 6 years ago, when I believe it was something like 8 years old). So I'd keep it as a backup, or possibly use it in a second system.

But regarding keeping it in the system along with the DEQX, my instinct is generally to have as little in the signal path as necessary. Also, as you can tell from the photos in my system description, my setup can't readily accommodate both units physically. But we'll see, of course, how the sonics work out with the DEQX installed in the configuration I described.

Best regards,
-- Al

Al, for the configuration you plan on using you won't need to worry about any manual time alignment as the 3 sets of outputs won't be feeding multiple power amps or subs (which is what they are really designed for). The only graphs you will need to interpret manually will be the in-room measurements at the listening position and that's very easy

That makes your setup much simpler as the HDP-4 will automate correction to speaker drivers driven by one power amp. It will hear your speakers as a single set of frequencies with any passive crossovers included in the signal path and adjust accordingly. You won't use the active crossover facility, just speaker correction to one stereo pair and the potential for room equalisation as you see fit

At a later date you have the opportunity to try all the other features, adding more power amps, speakers without passive crossovers, maybe subs etc. As long as you always measure with the power amps and cables linked to the drivers they will be running, you can even use different brands and wattages of amps for bass-mid-treble and DEQX calibrates and adjusts accordingly. Better to stick to one brand/rating though but it does allow you to adapt the system without needing to purchase 3 new sets of power amps in one hit

Regards Andrew