[KurtW]

The HeadRoom and the Jan Meier crossfeed do have some differences, so I can understand that some people may prefer one over the other although I'm a little puzzled by the big difference that kwkarth hears. But to be clear, the Porta-Corda's crossfeed is much more than simple blending of the channels.

I wondered if maybe the PC was different than the Corda, so I measured the frequency dependant time delays of the PC, and they are very similar to the ones in Jan's article on the Corda. At 100 Hz there is a 300 uS time delay, which, according to HeadRoom's article, corresponds to a 30 degree off axis response which they are also trying to simulate. I measured 220 uS at 500 Hz, 160 uS at 1KHz and 100 uS at 2 KHz. Of course the amount of crossfeed, like in the HeadRoom units, varied with frequency as well.

 

[kwkarth]

Some of the differences that I hear may be due to differences in source, interconnects or the soundstaging of the amps themselves. After all, I was making a real apples to oranges comparison. The Max fed with an HDCD-CDP through M950i IC's vs an 18v Porta Corda fed with a Sony DFJ61 PCDP. Not really a fair comparison. Although the sound of the PC is not unpleasant by itself, I just do not care for the "effect" or lack thereof of it's crossfeed whereas the crossfeed on the Max is absolutely wonderful in what it does to the soundstage of most material.

 

[M Rael]

If you want crossfeed facts, go to Headwize

One of the main differences between the two crossfeed approaches is in the way they treat mono information (information that the left and right channels have in common.) Meier prides himself that his crossfeed does not disturb the mono signal (the 'center' image in your head), while HeadRoom figures their method sounds more like a loudspeaker effect, on headphones. Meier describes his process as slightly lessening the perceived bass, while HeadRooms process gives an obvious perceived boost.

I erased all my previous content on this sad thread, because all the information exists at Headwize. There was no need for me to have approached this as a bonanza for opinions. From now on I'll start with Headwize before coming here. Sorry for the confusion Spad; this was a big waste of time and energy for me (too.)

 

[jude]

Quote:

Originally posted by M Rael ...And if you're reading this and its the year 2003, then it means you're doing a search on crossfeed and you finally found us. Hi there! And it also means Jude never did implement any kind of data base....

What do you mean by this, M Rael? Are you upset because I didn't do your research?

 

[KR...]

Quote:

There was no need for me to have approached this as a bonanza for opinions. From now on I'll start with Headwize before coming here.

 

[KurtW]

kwkarth, I think you're right. The Porta Corda is good competition for the Total Airhead but not in the same ballpark as the Max, as expected.

 

[M Rael]

Headphone reproduction isnt stereo.

'Stereophonic' by definition reqires a mixing of the left and right channels in space, so that the ear/head/brain combination can work together to produce the stereo effect.
Headphone listening is more correctly termed 'Biphonic.' Biphonic is what you get when two separate pickup channels are transmitted directly to each ear, as with headphones.

This relates directly to artificial crosstalk, obviously. True, crosstalk doesnt 'work' in the sense of equaling stereophonic reproduction, but it at least tries. I'm glad both HeadRoom and Meier are trying.

 

[Spad]

Quote:

Originally posted by KurtW kwkarth, I think you're right. The Porta Corda is good competition for the Total Airhead but not in the same ballpark as the Max, as expected.

Nor is the Porta Corda in the same league as the Corda HA-1, I think you'll agree.

 

[MacDEF]

I concur with Jude and kwkarth -- I can't listen to my Max without HeadRoom's processor. It just adds so much to the music, making it seem so much more "real."

I recently had the opportunity to compare the PortaCorda's crossfeed, and I have to agree with kwkarth. It's just not as natural-sounding; it doesn't make the music sound as lifelike or real as the Max's crossfeed does. Granted, the PortaCorda isn't in the same league as the Max, but given that the PortaCorda and Corda use similar circuitry for crossfeed (the Corda just has a switchable level), I think the PC is probably a pretty good representation of Jan's crossfeed circuitry. (I used the same source and headphones on both amps, BTW.)

 

[kwkarth]

Hey Mac, where'd the robot go on vacation? Florida?
cheers!

 

[KurtW]

Actually, I can listen to a majority of music without crossfeed, but there are certain CDs that I will not even bother to listen to with headphones without crossfeed.

MacDEF, you're using the same source and CDs to compare crossfeeds, which is good, but I agree with kwkarth that the amps themselves make a big difference. As Spad says, the Porta-Corda isn't in the same league as the Corda, let alone the Max. I think you had both one of the airheads as well as the PC at some point, MacDEF, did you compare the crossfeed circuits of these two amps? That's a much more fair comparison.

By the way, the Meier crossfeed can be used passively between a CD player and an amp, although the results depend a bit on the impedances of each. Ideally the CD player should have quite low output impedance (most portables aren't that low) and the amp have pretty high impedance. I have a little box that contains the components (3 resistors, 2 caps) that I can use with any amp. Of course, HeadRoom also sells a box that can be used between any CD player and amp just to add their "processor" crossfeed circuit. It's more expensive since it's an active circuit rather than passive, but should work equally well with any components. One could build a active Meier crossfeed box as well, which would be pretty much what the Corda is but with different connectors. You could use a Corda for this purpose. Of course the problem with active circuits, and even passive circuits to a lesser degree, is that they can degrade the sound to some auguable extent. Good ones, as in the HeadRoom and Meier boxes, don't degrade it much, but when people are worried about wires degrading the sound, you can imagine what resistors, capacitors and ICs do to the sound in comparison.

 

[kwkarth]

I can tell you that at this point, I cannot discern an audible degradation from having the Max between my source and the SAC. 1600 bux is sort of steep for a processor, but hey, it came with a free state of the art head amp!!

 

[MacDEF]

Quote:

Originally posted by KurtW MacDEF, you're using the same source and CDs to compare crossfeeds, which is good, but I agree with kwkarth that the amps themselves make a big difference.

I agree

Quote:

I think you had both one of the airheads as well as the PC at some point, MacDEF, did you compare the crossfeed circuits of these two amps? That's a much more fair comparison.

Unfortunately, I never had the two at the same time (the PC and the Airhead). However, I will say that -- from memory -- I preferred the PCs tonal balance to the Airhead, but I preferred the crossfeed on the Airhead to the PCs crossfeed.

 

[MacDEF]

Quote:

Originally posted by kwkarth Hey Mac, where'd the robot go on vacation? Florida?

After the strenous activity in the "Vote for the avatar" competition, he needed a vacation

He'd got a bit of a sunburn now (either that, or that's his best Andy Warhol picture).

 

[kwkarth]

Your robot is definitely one of the best all time avatars! Although my grandaughter is prettier!