Re: [slim] Re: Crossfeed Plugin
That's interesting, but what we really need is a DSP guru to design an IIR (or FIR, if necessary) filter that does the same thing. Anybody? On Sep 2, 2005, at 4:57 AM, Michel Fombellida wrote: bjackson Wrote: http://headwize.com/projects/showfile.php?file=meier_prj.htm The guy who wrote this article (Jan Meier) is the father of the Corda headphone amps which are indeed well known for their crossfeed circuit. Some more info is available on his web site (look at the link crossfeed filter in the left pane): http://www.meier-audio.homepage.t-online.de/ bjackson Wrote: Maybe call it something like: Expand Soundstage (Off, Low, Middle, High) or something? And why not Crossfeed :-) Michel -- Michel Fombellida ___ Discuss mailing list Discuss@lists.slimdevices.com http://lists.slimdevices.com/lists/listinfo/discuss ___ Discuss mailing list Discuss@lists.slimdevices.com http://lists.slimdevices.com/lists/listinfo/discuss
Re: [slim] Re: Crossfeed Plugin
On 9/2/05, Michel Fombellida [EMAIL PROTECTED] wrote: And why not Crossfeed :-) I'd say that would be a bit too easy to confuse with crossfade (as in song transitions). But really, as long as it's not called SlimDSP X-TREME-HeadphoneMAGIC 2000++,(*cough*X-Fi*cough*), I won't mind. :) - Jacob ___ Discuss mailing list Discuss@lists.slimdevices.com http://lists.slimdevices.com/lists/listinfo/discuss
Re: [slim] Re: Crossfeed Plugin
seanadams wrote: A fine idea - please file a request at bugs.slimdevices.com. It's something we'd need to do in firmware, right at the end of our audio process. Actually, you could do this on the server by piping the audio stream through the appropriate processing program. What kind of delay would you want? Obviously the delay and mix levels would be configurable but I'm guessing you'd want a range of 0 to 1000uS or so? There is a whole load of research on this, but I can't find the links right now. I'll have a scout around. Also isn't there another name for this besides crossfeed that wouldn't be confused with the crossfade feature? I'm sure the work to which I refer is called something other than crossfeed. Again, I'll see what I can find. R. -- http://robinbowes.com If a man speaks in a forest, and his wife's not there, is he still wrong? ___ Discuss mailing list Discuss@lists.slimdevices.com http://lists.slimdevices.com/lists/listinfo/discuss
Re: [slim] Re: Crossfeed Plugin
Robin Bowes wrote: seanadams wrote: A fine idea - please file a request at bugs.slimdevices.com. It's something we'd need to do in firmware, right at the end of our audio process. Actually, you could do this on the server by piping the audio stream through the appropriate processing program. What kind of delay would you want? Obviously the delay and mix levels would be configurable but I'm guessing you'd want a range of 0 to 1000uS or so? There is a whole load of research on this, but I can't find the links right now. I'll have a scout around. Also isn't there another name for this besides crossfeed that wouldn't be confused with the crossfade feature? I'm sure the work to which I refer is called something other than crossfeed. Again, I'll see what I can find. OK, I've not found the links I was looking for, but this technology is related to Head Related Transfer Functions (HRTFs). Somewhere I've seen a site that demonstrates a pseudo-HRTF, i.e. an artificial approximation and provides a couple of sample files illustrating the effect. If only I could find it ... R. -- http://robinbowes.com If a man speaks in a forest, and his wife's not there, is he still wrong? ___ Discuss mailing list Discuss@lists.slimdevices.com http://lists.slimdevices.com/lists/listinfo/discuss
Re: [slim] Re: Crossfeed Plugin
On Thursday 01 September 2005 09:32, Robin Bowes wrote: Robin Bowes wrote: seanadams wrote: A fine idea - please file a request at bugs.slimdevices.com. It's something we'd need to do in firmware, right at the end of our audio process. Actually, you could do this on the server by piping the audio stream through the appropriate processing program. What kind of delay would you want? Obviously the delay and mix levels would be configurable but I'm guessing you'd want a range of 0 to 1000uS or so? There is a whole load of research on this, but I can't find the links right now. I'll have a scout around. Also isn't there another name for this besides crossfeed that wouldn't be confused with the crossfade feature? I'm sure the work to which I refer is called something other than crossfeed. Again, I'll see what I can find. OK, I've not found the links I was looking for, but this technology is related to Head Related Transfer Functions (HRTFs). Somewhere I've seen a site that demonstrates a pseudo-HRTF, i.e. an artificial approximation and provides a couple of sample files illustrating the effect. If only I could find it ... if what you are referring to is the cross-feeding stuff to make headphones sound nicer, then HeadRoom has some docs here: http://www.headphone.com/products/faqs/about-headroom-crossfeed/ but it doesn't actually tell you exactly how to do it (obviously). My iriver hd140 also includes something similar named SRS (http://www.srslabs.com/) but it generally sounds horrible (to my ears). However they have many demonstration files available (http://www.srslabs.com/Demonstrations.asp) that I haven't had a chance to listen to yet in a controlled environment. Alex ___ Discuss mailing list Discuss@lists.slimdevices.com http://lists.slimdevices.com/lists/listinfo/discuss
Re: [slim] Re: Crossfeed Plugin
Alex Twisleton-Wykeham-Fiennes wrote: if what you are referring to is the cross-feeding stuff to make headphones sound nicer, then HeadRoom has some docs here: http://www.headphone.com/products/faqs/about-headroom-crossfeed/ but it doesn't actually tell you exactly how to do it (obviously). Well, it comes pretty close: The current HeadRoom crossfeed circuit uses a two-stage active filter that provides about 400 uSec of delay and a gentle frequency response roll-off starting at about 2 kHz. The left crossfeed signal is mixed in with the right channel’s direct signal (and vice versa) at a level about 8dB lower. However, that's not the link to which I was referring. My iriver hd140 also includes something similar named SRS (http://www.srslabs.com/) but it generally sounds horrible (to my ears). However they have many demonstration files available (http://www.srslabs.com/Demonstrations.asp) that I haven't had a chance to listen to yet in a controlled environment. That's not it either - this is going to bug me! R. -- http://robinbowes.com If a man speaks in a forest, and his wife's not there, is he still wrong? ___ Discuss mailing list Discuss@lists.slimdevices.com http://lists.slimdevices.com/lists/listinfo/discuss
Re: [slim] Re: Crossfeed Plugin
On Thursday 01 September 2005 17:32, ephemere wrote: (1) Doing it on the server is probably not the right thing for anything other than a PCM stream because it would require a decode-encode step. Agreed. (2) I'm no expert, but it's more complicated than just a delay and gain adjustment. The process is usually frequency-dependent. The previous quote from headphone.com is frequency dependent because the crossover for the feed into the delay line is described as a gentle frequency response therefore the amount of delayed signal will increase as the frequency increases. Or are you suggesting that the delay time would alter with frequency as well? (3) One could make up a name like headphone virtualizer instead of crossfeed. would it not be a speaker virtualiser because it makes headphones sound like speakers? :-) Alex ___ Discuss mailing list Discuss@lists.slimdevices.com http://lists.slimdevices.com/lists/listinfo/discuss
