Anything new with digital room correction?

Rives-

Your post makes it sound like Sashav and others would need new equipment which is totally false. Almost every high end CD player allows the D/A conversion to be bypassed so no one has to buy new equipment to use the Lyngdorf room correction equipment. This is no more complicated than using a digital out from your CD player which is usually toslink or digital RCA and occassionally XLR.

Sashav, a digital box like the DEQX can do a number of things that can not be done in the analogue domain. Well, some of these things CAN be done, but not without a lot of experimentation and a lot of extra circuitry in the box. If you compare a product like the DEQX with a Marchand XM144 crossover, these are the advantages of the DEQX:

- steep crossover slopes, up to 100dB/oct. Marchand can only do 24dB/oct and introduces phase issues. The Marchand's x-over point and slope can be adjusted by purchasing a card ($10) compared to a few clicks of a mouse button with the DEQX.

- group delay. Both products implement this, DEQX via your laptop and Marchand via a drop in card.

- room correction. DEQX can correct a near infinite number of frequencies. Marchand attenuates or boosts selected frequencies via insertion of notch filters.

On the face of it the DEQX is more flexible and easier to tune. However (as I have said many times) the problem with the DEQX is that it drags the overall quality of your system down. I have heard a DEQX with a high quality analogue source. It makes the turntable sound like a cheap CD player.

The biggest problem is (as you say) it robs the sound of dynamics and subtlety. The frequencies that suffer the most are the midrange and treble. If you could think of a way to use the DEQX only in the most problematic frequencies - 200Hz and below - you would have the best of both worlds.

I recently experienced an audio epiphany with the DEQX. I now recognize that room correction alone provides some benefit, but is nothing compared to correction of phase and group delay.

The other gotcha - DEQX is very system dependent. On my system it brought obvious benefits along with obvious losses. I would have to give up some things (transparency, dynamics, resolution) to gain others (coherency, accuracy). How much YOU benefit would depend on the balance of faults and strengths of your system. So I would shy away from making an endorsement of this product, or any other product.

Mmike: It's true most CD players have digital out--but in that case where will you do the D/A. Most Cd players do not have a digital input. Some very high end ones do, but most don't. And I'm also considering the possibility of analog sources such as a turntable or tuner. I did not mean to imply "you have to buy new equipment." I was only trying to point out some potential caveats. That's to say there is one and only one way to accomplish the goal. It's more a matter of helping those reading this post to define their goal and then what approach might work best. Obviously, it's not the same answer for everyone.

Rives-

I was assuming Sashav has a preamp with phono or if not, and he needs it, he could add a separate phono stage. Your last post says most CD players don't have a digital in but I think you meant out which I don't agree with. Most high end one box CD players do have a digital out, and a high end transport would work even better. While it's true the D/A conversion has to happen somewhere but in the case of the Lyngdorf room perfect system the unit has an excellent D/A in it.

Thanks for clarifying though (and responding to my post!) as I felt your first post suggested Sashav would need new equipment and should abandon digital correction which may not the case. In the end I strongly suggest keeping an analog or digital source as far as possible. Thanks for clarifying. I think we're both making useful suggestions so Sashav can make the best improvements he can. :)

Sahav says, "Yes, I have a couple of nulls above 100Hz, but not exceeding 3-4dB."

How do you know this? How do you know what is happening in the lower freq (20hz to 100hz)? Just curious.

Bob