A how to for a PC XO.

[geofstro]

Actually the beauty of the system proposed by Shinowiban using Console is that whatever sound source you are using whether internal to the PC or external sources can take advantage of XO's and Room Correction.

It was before I came across this thread that I was limited to foobar, since I only knew about the convolver and crossover foobar plug-ins. Foobar is still my favourite music player on the PC. I no longer need to use it's convolver, etc, though and I'm no longer limited to Foobar as a sound source.

Hope it helps

Geoff

[NurEinTier]

Thanks.

Being a newbie the complexity of crossovers almost scares me back to the commercial speakers.
If there's a viable option not to use them at all I have to know all about it.

Re-reading the whole post.

[wigginjs]

Shin/Ed:

I'm going to give the PC XO thing another shot, probably with linux this time. I'm curious, how do you guys cope with the delay the PC XO causes with respect to any video being played? I will be using my PC XO as an in-line XO/DRC unit, so it will only be processing external inputs and not playing back from the unit itself. I plan to run all of my audio through it including TV from a cable box and DVDs from a DVD player, what method can I use to make sure the video and audio are in sync?

[ShinOBIWAN]

Hi motion

The delay thing is unadavoidable when using using external video sources such as VCR, DVD, Xbox, TV etc.

There's a few option:

First off is an external video time shift box. I've got around 75ms delay using Waves LineEQ and Voxengo which is a lot when you start watching/listening to TV because the lip sync is slightly off. But with a video time shift box you can sync external sources back to the processed audio. Some plasma/lcd screens and highend projectors have a similar gadget built in but for the audio delay because of all the processing time required for the video such as upscaling, deinterlacing etc.
I have no idea how much they cost or where to get one from but I should imagine they are pretty easy to comeby in the broadcasting market, where they will primarily be used.

My solution is to use the PC as the source with Theatertek and Zoomplayer Pro used for DVD's, HiDef material and general video. And I've also got a Blackgold digital TV card installed. All these have lipsync options to delay the video by a certain amount. So for me everything is perfect.

For audio only the delay doesn't matter.

The other option is to use standard IIR digital filters and DRC which will get you around 15-20ms delay at the very most. With that you don't need any sync options because the delay isn't detectable even when watching someones mouth closely on a movie or TV.

Its the FIR filters that cause the big delay of around 60ms But you've got a few options to jump that hurdle if you so choose.

[ShinOBIWAN]

Well I'm all confused again now

It appears that the console method sucks pretty badly....

I've just taken my drivers out of the cabinet again and was playing with console/Wave LineEQ along with the ATC bass driver in free air. There's a ton of distortion evident, I really don't know why I didn't hear it before but a good guess would be that the bass frequencies are now lowered to much greater extent and the crossover point becomes much more audible.

The distortion actually sounds like a mechanical fault on a damaged driver ie. buzzing at moderate to loud levels and also resonances. The details at the time of testing was an XO frequency of 430hz with a Q of 6.5 using LineEQ broadband mono.
I've also tried Algoritmix Orange and Red PEQ's, Waves C4, Waves Parameteric EQ and Voxengo Curve EQ. All display the same trait.

Its been driving me crazy since yesterday and I've checked and triple checked all outputs/inputs for clipping and even lowered them just to be sure - the problem is still evident.

I'm wondering if its the fireface doing this? It sounds fine on full range material passed through the ATC but it could be that the problems are being masked with the overall wash of a full range signal. If you turn the XO back on, its very clear to hear the problems even at moderate levels and extremely obvious at high ones.

I've been through several other woofers and all display the same problems so its not a blown driver as I originally thought it could be. After narrowing it down its definitely a problem somewhere within the audio processing. Possibilities are console itself, the EQ software used to create the filters - doubtful since so many show the same problem or it could be the fireface/RME drivers?

Can anyone else try out a similar situation and let me know if this is a problem related to my setup or if there is an inherant weakness in the whole Console XO/DRC setup?

I'm going to try removing Console from the loop by using AdaptX (a plugin client for winamp) tommorow. I also plan to try using foobar with BruteFIR and generating my own filters.

Thanks for any help or advice offered

[RR]

Hi ShinOBIWAN,

I'm not sure if you are doing linear phase crossovers, but if that is the case, I could hear the ringing inherent to them when listening to a single way, particularly the bass driver, without the others.

It is like an added buzz at the crossover frequency. When listening to the whole speaker it cancels with the next driver "inverted ring" and becomes inaudible.

Is this similar with what you notice in your setup?

[jtavan]

I think RR is likely correct on this. I don't see that it could be a driver or hardware issue. It could be the XO software you're using. I don't see it being console...it doesn't know or care what sound you're passing through its plugins. If it's just ringing filters, I don't know that you'll be able to solve it for a single driver in free space. But...do you need to?

I was having a bit of a scare yesterday listening to a nice choral recording when I heard a nasty crackling like clipping in the midrange during one of the loudest passages. Except that my midrange is a compression driver which should be able to blast through the passage without any difficulty. And when I turned the overall volume down, the problem didn't go away. The culprit? It turns out somehow Replaygain had been turned back on in foobar2000, and the +6dB or so it was adding to the track was causing clipping in foobar's output. Yech. Replaygain is mmmbad.

[ShinOBIWAN]

Thanks for the suggestions and comments.

Still working through the problem and trying alternatives. If there's any other idea's folks have please let me know.

I've narrowed a couple of things down such as the fact that its not Console as winamp with adaptx running Waves LineEQ also exhibits the same behaviour. As well as this I've tried foobar to make sure the player isn't causing trouble and its not BTW. I've tried Wave and ASIO output both exhibit the same behaviour, so not a problem there either.
I've also tried physically routing the signal rather than using the loopback on the RME fireface just incase that was causing the trouble - no change.
Also checked the levels and clipping many times and all seem to be fine. Its worth noting that the distortion I'm talking about sounds very much like a type of clipping distortion ie. distorted and resonant sound with digital like 'poping/cracking' noising which are apparent at all volume levels but only really noticable from the listening position at high volume level's.
Another observation is that the distortion definitely seems to get progressively worse the lower down the frequency scale you go when selecting a crossover point, for example at 400hz its very audible but at 6Khz its sounds fairly normal. Again I'm not sure if there's masking going on here.

So narrowing it down, one possibility is the plugins I'm using - but why does Waves C4 which is an IIR based filter still exhibit the same distortion if its pre-echo artifacts? Not to mention the fact I've tried Algorthmix Orange & Red PEQ's and Voxengo Curve EQ.

Another possibility is the RME fireface itself and any related drivers. I've not 100% assured myself that, whilst playing a fullrange signal with no digital XO or DRC taking place, there isn't any distortion taking place, if it is then I can't hear because of the fact that there's so much going on. So if there is distortion its not obvious with a full range signal.

I've come to the conclusion that its actually so audible that it must have been taking away something from the sound even when running a full multiway speaker. I'll try to capture the sound and post it on here for other to hear as that would tell far more than a few paragraphs could.

Started pricing up a DEQX just in case this doesn't work out

[oehlrich]

Originally posted by cdwitmer
1) What is the best way to pipe SACD into such a PC-based XO? I have been looking at the dvdupgrades.ch S/P-DIF add-on board for multi-disc players, in conjunction with an add-on board for the LynxTwo. However, if there are more cost-effective solutions, I'd like to hear about them.

cdwitmer,
just look here!

http://freerider.dyndns.org

Charly

[Sheldon]

Originally posted by ShinOBIWAN
Thanks for the suggestions and comments.

Still working through the problem and trying alternatives. If there's any other idea's folks have please let me know.

I've narrowed a couple of things down such as the fact that its not Console as winamp with adaptx running Waves LineEQ also exhibits the same behaviour. As well as this I've tried foobar to make sure the player isn't causing trouble and its not BTW. I've tried Wave and ASIO output both exhibit the same behaviour, so not a problem there either.
I've also tried physically routing the signal rather than using the loopback on the RME fireface just incase that was causing the trouble - no change.
Also checked the levels and clipping many times and all seem to be fine. Its worth noting that the distortion I'm talking about sounds very much like a type of clipping distortion ie. distorted and resonant sound with digital like 'poping/cracking' noising which are apparent at all volume levels but only really noticable from the listening position at high volume level's.
Another observation is that the distortion definitely seems to get progressively worse the lower down the frequency scale you go when selecting a crossover point, for example at 400hz its very audible but at 6Khz its sounds fairly normal. Again I'm not sure if there's masking going on here.

So narrowing it down, one possibility is the plugins I'm using - but why does Waves C4 which is an IIR based filter still exhibit the same distortion if its pre-echo artifacts? Not to mention the fact I've tried Algorthmix Orange & Red PEQ's and Voxengo Curve EQ.

Another possibility is the RME fireface itself and any related drivers. I've not 100% assured myself that, whilst playing a fullrange signal with no digital XO or DRC taking place, there isn't any distortion taking place, if it is then I can't hear because of the fact that there's so much going on. So if there is distortion its not obvious with a full range signal.

I've come to the conclusion that its actually so audible that it must have been taking away something from the sound even when running a full multiway speaker. I'll try to capture the sound and post it on here for other to hear as that would tell far more than a few paragraphs could.

Started pricing up a DEQX just in case this doesn't work out

I'm doing the DEQX route now, but counting on you to work out the PC as it, as you have said, should ultimately offer more. Check this thread, you might be able to stir up John Hancock and see if he can offer you the benefit of his experience: http://www.diyaudio.com/forums/showt...552#post205552

Sheldon