Room Correction/Crossover


I am considering going to an active satellite/sub scheme. The subs would be active. I am absolutely sold on room and frequency/phase correction, so that's a necessity. Basically, I do not wish to give up 1) my amp (VAC Phi Beta 110i), 2) the DAC (Berkeley Alpha), or, most importantly, 3) my vinyl. The obvious choice, at least when it comes to room correction and digital crossover, is the DEQX HDP-3. Lyngdorf would also be a possibility, but it's unclear to me whether their products provide crossover capabilities.
So, my questions are, first, can anyone clear up that last bit regarding Lyngdorf, and second, do you have alternative suggestions? I would have a very strong preference for a one box solution. Thanks in advance.
curriemt11
Check out my system. It will do what you want but 2 boxes.. computer and pro audio interface.

I'm not sure about phase correction but I'm pretty sure you can get a plug in that works with Pure Music to do that. I'm currently triamping and using Fab Filter ProQ plug in for EQ.

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The TacT 2.2 series and later (which I own) and the Lyngdorf, I believe, include an amazing amount of crossover frequencies and slopes. I went from a complex cone based and stereo biamped system into a hybrid Sanders Sound System with 48 DB slope digital crossovers.

In addition, of course, are phase controls ("moving" your speakers to within 1/4" of each other), parametric eq, and their big focus, room equalization, plus the sort of crazy option for the truly obsessed of eq'ing different labels for all to common non RIAA curves: really not so crazy if you have older labels/reissues or some of the really harshly eq'd or Aphex'ed stuff.

Like most computer based stuff in the hands of older a'philes, the learning curve is steep, but good peer support is available at Yahoo and TacT groups.

For a good hi-end system, later models or MauiMOds are just a plain necessity, esp. the DACs. And yes, I hate the ADC conversion necessary from my $20+K table and Sonus Veritas Milan phono pre, but compared to a non eq'd room, I (and you) have to balance the gain/loss. I don't like a purely analog sound at reference quality (which I like to think I am getting closer to) except through my Stax phones, when any normal (even treated) room will totally screw up nearly everything sonically unless perfectly and professionally and very expensively built for audio purposes. Even then, that's only a fixed EQ
issue and doesn't address bizarre sounding (steep and real high) crossover frequencies or phase anomolies never approached by analog crossovers or by-guess and by-God phase switches and dialed phase controls (honestly, what are your chances of you, your room, your furniture layout, your reflection patterns and your best tape measure)of hitting the sweet spot regarding phase alignment in a complex system with stereo subs and satelites?)
Clarification.. if by phase you mean time alignment of the drivers then yes, Pure Vinyl will do that too.

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TacT - I had forgotten all about them. Thanks for the jar to the memory.

The audiophile purist in me says 'stay the hell away from adc/dac for my vinyl'. However, I work with digital filters all day, every day (I'm a geophysicist), and I know good and well what the relative capabilities are vs. analog types. There's no doubt in my mind that the room is not only the weakest link in any decent system, but is also the most neglected factor. I'm ready to make the sacrifice for a slight loss in the analog arena in order to reap major gains in room/phase/frequency correction.

Jeffb, thanks for your response. I can see that we're very much on the same wavelength (pun intended). DEQX seems to be a third alternative. Unfortunately, as far as I can tell, none of the three options appear to be available without the preamp functions. My single biggest concern about this is volume control. I REALLY hate the idea of running things through both an analog control (on the VAC) and a digital one (on the TacT/Lyngdorf/DEQX). It may be just lingering prejudice, but my experience has been that this is where much of the damage to a signal can occur.

Herman, this is quite interesting. Your setup seems to do pretty much what's needed, at a lower overall cost, but perhaps representing a somewhat more complex solution. I will investigate further. Thank you!
I own the Lyngdorf TDAI 2200 and can confirm that at least some of the Lyngdorf products allow users to choose among many crossover types and to choose the specific crossover frequency. I'm not sure though which of their several products have this functionality, but would think it is covered in the product descriptions on their site.

As a side note, I was wary of, but am impressed with the AD conversion that is an option on the TDAI 2200. The amp itself is wonderful as well.

Depending on how you address the crossover issue, D-Speaker's Anti Mode 8033 is a cost effective way to address time and frequency problems below 140 Hz (not sure about that cutoff but somewhere in that area).
Thanks again for the replies. I've found (and ordered) what I hope is the best answer - the Lyngdorf RP-1. It will slot in between my amp's pre out and power in jacks, and provide both crossover and room correction functions.
Hi Curriemt this comes a little late for you given that you have already ordered your unit, but I would strongly suggest that you forget about trying to correct your room electronically. I had a look at your very impressive system and it appears that you are fortunate enough to have your own "man-cave" - if you have complete freedom to do what you want with your room, it is far better to achieve room correction using room treatments.

Earlier this evening I was reading Jools' excellent write-up on his TaCT unit here on A'gon: http://forum.audiogon.com/cgi-bin/fr.pl?aamps&1006563704&&&/Opinions-on-TacT-RCS-Room-Correction-Sys

AFAIK the Lyngdorf is a rebranded TaCT.

My own experience with my DEQX leads me to agree with everything he said. I am not afraid of the learning curve, but what he said about the feeling of neurosis is very true. The feeling that you can squeeze out more performance, along with the realization that some discs sound horrible and some sound better - and the key to consistency is to go back to a simple system.

You already know about the potential performance hit from the AD conversion. I think the severity of the "hit" varies from system to system. The ideal system is one which feeds digital signal straight to the processor and the worst would be one like yours which has a high end analog rig.

But the real nail in the coffin for me came when I realized that all room correction packages only correct for problems in the frequency domain, and even then at one position only. If you walk around your room with a RTA and some pink noise, you will see that the F/R aberrations will vary quite wildly, sometimes by as little as moving the RTA 1 foot to the front or back. This means that your room correction will sound OK at the sweet spot, but horrible everywhere else.

Furthermore, room correction does nothing for time domain problems such as ringing or echoes. If you have a live sounding room, room correction will do nothing. Remember that the sound that you hear is a combination of the direct wave from the speaker, and a time delayed wave (or waves) caused by room reflection. The proportion of each will vary from room to room, and the unit will not be able to do anything about that.

Inevitably, the measurement you take will result in horrible sound and you will end up having to tweak it yourself anyway. This feeds back into the neurosis that you are not getting it right.

The real value of the unit is what you can learn from it. I can see the peaks and dips of my room, and I know what it sounds like if I get it as flat as possible. I have removed the DEQX from my system. My next step is to get a set of Helmholtz resonators made to my specifications to get rid of some nasty bass peaks which I identified with the measurements. This will not only remove the peak, it will also remove ringing.

Ultimately, the best approach is to make your room sound as neutral as possible, so that your room correction device has to do as little work as possible. I do not know what your room is like, so I do not know how much benefit you will gain from this device. If you have a really bad room, you will have to look at other solutions in place of (or in addition to) your Lyngdorf.

Good luck with it.