[JaZZ]

Quote:

Originally Posted by drarthurwells The effect of crossfeed on multiple tones playing simultaneously is an expanded soundstage but with more congestion and merging of instruments into one mass. Some people like the soundstage expanded.

I guess you're talking of HeadRoom's crossfeed (which I don't know). In any event that's not how the Meier crossfeed works, which is how I have explained: a simple monophonization of low frequencies.

 

[rickcr42]

I have available and at times use a crossfeed when it seems a better course to follow than the left/right channels played straight through.Reasoning ?

Some early stereo recordings are no more than two mono channels sent to either the left or the right side with no "middle" content at all.Why ?
Lack of stereo recording technique by the recording engineer in the early stages of the transfer from mono to stereo and actual transferrence of mono recordings to a "psuedo stereo" format.What you get is individual instruments or vocals grouped into one ear or the other and this is very unnatural.

The second reason is all about the actual theory of what "Stereo" is and what /how it is meant to be recorded and played back.When doing a live recording the microphones are set up with the end use in mind.If that end use is playback over stereo loudspeakers then it is known in advance there will be "leakage" from the left channel to the right and the right channel to the left in the actual listening room due to the two channels not being isolated.Knowing there will be a natural "mix" the mics are placed accordingly for the best overall stereo image when played back on speakers.Not headphones.
For headphone other miking techniques are used but this does not translate well when used for loudspeaker monitoriung so a decision is made up front what the intended end use will be for that recording and anything else will be a comprimise.
This comprimise is not so extreme that it takes away from musical enjoymernt of the recording if played back other than as intenede but will not be optimal either so as in most things a "fix" is devised by some deep thinker somewhere As far as I can see it was Linkwitz to bring the crossfeed to general view but i have crossed paths with a French site that has earlier references to a crossfeed device.Being scans I could not use an online translator to read the text but i weasled out enough words on my own combined with the schematic to know what I was seeing.
what the crossfeed attempts to do electronically is what a loudspeaker does naturally.bleed some left channel signal to the righ and right channel signal to the left which in theory will give a "center" to what would otherwise be isolated left and right signals when played back on headphones.the "hole in the head" effect where unbless you head is hollow and the sound goes in one ear and out the other the left can not reach the right and visa versa.
Done right it adds to the music rather than takes away and makes the soundfield more diffues and "there" than it otherwise would be.

Chu moy took the original Linkwitz model and tweaked it a bit for better performance and Jan Meier took this to the next step but it is Headroom that had the forewsight to actually add this to a commercial product and put the word "crossfeed" into the audio jargon and make a fringe device mainstream and socially acceptable.for reasons I won't go into it is my beleif they get it more right than anyone else but that is just a subjective opinion.Other companies seeing the potential for the technolgy liscenced this from Headrom for use in their own products.Audio Alchemy included it in their headphone amp (a nice amp if you can find one) and XXXXX (forgot the company name-Canadian).Stax even had a similiar stand alone device once.As far as I know off hand the only commercially available headphone-crossfeed devices are the Headroom models and from Meier Audio :

http://www.meier-audio.homepage.t-online.de/

where a really extensive explanation of the crossfeed is available AND what is to me the best DIY based solution which is a complete crossfeed device plus a frequency compensation network to tailer the overall response of the device making it very flexable :

http://www.meier-audio.homepage.t-on...sivefilter.htm

Other headphone crossfeeed examples are the original Linkwitz filter
http://www.linkwitzlab.com/images/graphics/hdphon1.gif

and http://www.linkwitzlab.com/images/graphics/hdphon2.gif,

The original Chu Moy "variant" from the Headwize Library http://headwize.com/projects/showfil...=cmoy1_prj.htm,

the Chester Simpson Linkwitz Variant
http://headwize.com/projects/showfil...mpson2_prj.htm,

the original Jan Meier circuits from the Headwize Library
http://headwize.com/projects/showfil...=meier_prj.htm and http://headwize.com/projects/showfil...meier2_prj.htm,

Ohman variant http://headwize.com/projects/showfil...mhagen_prj.htm

finally John Connover's offering
http://<br /> http://www.johncon.co...Amp/index.html

Kinda a long winded response even for me but basically my take on the Headphone Crossfeed is they have merit and the science makes sense plus they do no harm by having them available for those times when not having one is a real disadvantage if having a good stereo image is important to the user.

As always YMMV and probably will

 

[Dick Danger]

I don't really give a rat about the why's, where's, and how's, I own a Corda Cross and I LOVE it.

 

[brianknewbie]

Quote:

Originally Posted by drarthurwells Listen to a single tone on crossfeed and the repeat without crossfeed. Notice with crossfeed the tone is slightly larger in space - expanded. Howver its edges are blurred. It also has slightly more volume. Without crossfeed the image is more focused with more clearly defined boundaries within empty space. The effect of crossfeed on multiple tones playing simultaneously is an expanded soundstage but with more congestion and merging of instruments into one mass. Some people like the soundstage expanded.

This is a very good description of what crossfeed is like, for me at least.

I was fortunate to be able to spend some time with the HeadRoom Millet Hybrid amp and played with crossfeed on/off. I found that the result was subtle but I did prefer crossfeed enabled for the older recordings that I was listening to at the time.

 

[drarthurwells]

Quote:

Originally Posted by JaZZ I guess you're talking of HeadRoom's crossfeed (which I don't know). In any event that's not how the Meier crossfeed works, which is how I have explained: a simple monophonization of low frequencies.

Yes, I am talking Headroom crossfeed and don't know how the Meier works. Does it leave frequencies above 200 hz alone? Below 200 Hz crossfeed would have litle effect on imaging, but why would you restrict crossfeed in this way (assuming it only affects bass)?

 

[dariusf]

I have been using crassfeed most of the time for a few years and I find it having a major effect on how long I can listen to music. With out it with alot of recording I experience listing fatigue after time.

PinkFloyd used to make an awesome little crossfeed he called x-feed that I purchased from him a few years back. I would contact him to see if he can make/sell you one.

 

[Skylab]

Yeah, I also really prefer to use crossfeed, it sounds MUCH more natural to me. I have stuck with Headroom amps mostly for that reason mainly (although I am drooling over the Meier Audio PreHead MkIII...)

 

[dariusf]

I forgot to mention that the nice thing about PinkFloyd's x-feed was that it was I think around $50 if memory serves me right.

 

[JaZZ]

Quote:

Originally Posted by drarthurwells Yes, I am talking Headroom crossfeed and don't know how the Meier works. Does it leave frequencies above 200 hz alone? Below 200 Hz crossfeed would have litle effect on imaging, but why would you restrict crossfeed in this way (assuming it only affects bass)?

I guess 200 Hz is still slightly affected, but I don't have any data about it. Well, that's just a different approach to leave the rest of the frequency spectrum unaffected. And it really works, because ping-pong stereophony is much less annoying when only mids and highs are concerned than it is with low frequencies. And it also somewhat resembles the natural crossfeed in this characteristic, the more so as it implies a corresponding phase shift simulating the time offset between the ears.

 

[rickcr42]

Does it leave frequencies above 200 hz alone? Below 200 Hz crossfeed would have litle effect on imaging, but why would you restrict crossfeed in this way (assuming it only affects bass)?

Crossing over too high would destroy and stero imaging because of the non-selective blend and if the blend were full badwidth it would in essence be no more than a mono control.Far easier to implement with a couple of resistors alone.Too low and you would never notice the effect.The goal is selective mixing to remove the shading effects added to the music by the human head (something accounted for at the recording stage for binaural playback which is a headphone specific recording technique that would sound as unnatural over loudspeakers as stereo can with headphones)

 

[JaZZ]

Quote:

Originally Posted by rickcr42 Does it leave frequencies above 200 hz alone? Below 200 Hz crossfeed would have litle effect on imaging, but why would you restrict crossfeed in this way (assuming it only affects bass)?

Why not? Why would you want to have other things affected? I think frequencies above 200 Hz are affected too, but to a diminishing degree.


Quote:

Crossing over too high would destroy the stereo imaging because of the non-selective blend and if the blend were full bandwidth it would in essence be no more than a mono control.

As mentioned, (just) the low-frequency range is monophonized, the rest should be unaffected, but of course there's a large transition zone (reaching up to approximately 1 kHz or even higher). Yes, there's an audible corruption of the stereo image, but it's tolerable and in some cases -- those which crossfeed is meant for -- highly preferable to a one-sided bass tone. Luckily there's a stereo switch for deactivating crossfeed when it's not needed, thus with most (modern) recordings.

 

[bowlofjokes]

Well,, I'm learning.......Thanks for all contribution to thread

 

[drarthurwells]

Quote:

Art: Does it leave frequencies above 200 hz alone? Below 200 Hz crossfeed would have litle effect on imaging, but why would you restrict crossfeed in this way (assuming it only affects bass)? rickcr42: Crossing over too high would destroy any stero imaging because of the non-selective blend and if the blend were full badwidth it would in essence be no more than a mono control.Far easier to implement with a couple of resistors alone.Too low and you would never notice the effect.The goal is selective mixing to remove the shading effects added to the music by the human head (something accounted for at the recording stage for binaural playback which is a headphone specific recording technique that would sound as unnatural over loudspeakers as stereo can with headphones)

Art: I assume that the shading effects of the head are the head's blocking out sound between headphone drivers, wher esome such sound crosses over in the room with speakers. And yes, recordings tend to count on this speakers-in-room effect in the way they record. Headphones nullify this effect and give sound tha tis isolated in specific space - sometimes allowing vast holes in the middle and sound far in space to one side or the other. Crossfeed expands the instrument space - spreading it out in space - a single horn note can occupy 50% of the soundstage under crossfeed. Thus, tones are smeared and mudied, and inner detail in complex passages is lost with crossfeed.

Add to the problem of crossfeed is that it adds electronics in the signal path, just as equalization does, and this has to degrade the signal, however slightly.

No doubt the bigger and more filled-in soundstage is often desirable when inner detail is not important to the listener. There is no free lunch - either crossfeed or no crossfeed has its good points and it bad.

 

[drarthurwells]

Quote:

Originally Posted by JaZZ I guess 200 Hz is still slightly affected, but I don't have any data about it. Well, that's just a different approach to leave the rest of the frequency spectrum unaffected. And it really works, because ping-pong stereophony is much less annoying when only mids and highs are concerned than it is with low frequencies. And it also somewhat resembles the natural crossfeed in this characteristic, the more so as it implies a corresponding phase shift simulating the time offset between the ears.

You have made some excellent points. Crossfeed limited to 200 HZ or below would be somewhat meaningless since bass notes have such large waveforms - they are already widespread - expanded - and need no further expansion - not that some crossfeed wouldn't enhance the bass effect - it would, but it is just not as important as expanding the soundstage localization of treble notes with a much smaller waveform.

 

[gpalmer]

Quote:

Originally Posted by dariusf PinkFloyd used to make an awesome little crossfeed he called x-feed that I purchased from him a few years back. I would contact him to see if he can make/sell you one.

He doesn't sell that anymore...