netchris

I want to do active crossover inside the computer, and I currently have a M-Audio Revolution 7.1 which does support ASIO 2. However, the cost of software looks like it could be pretty high.. CPU use is another consideration, because in every review I've seen, the M-Audio card eats more CPU than Audigy, and I don't know how CPU intensive a 31 band EQ and crossover is.

So if I'm forced to take the low road and go with kXproject drivers.. How does my current card compare to these two:

http://www.newegg.com/Product/Produc...82E16829102011
http://www.newegg.com/Product/Produc...82E16829102002

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durwood

noooo....are you defecting? ha! J/K


Well, problem with those are that they don't work with the Kxdrivers. You have to find an original Audigy or Audigy2. There was a compatibilty list I posted somewhere. It's also on the kxproject website.

What features do you need for audio processing anyway? The 31 band VST plugin didn't eat up much resources. Did you want crossver capabilities from your soundcar? If not not then you don't even need an ASIO card.

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netchris

I do plan on using crossover in the carputer.

When I started the post I actually thought that my card didn't support ASIO for some reason, and was attracted to the Audigy cards (whatever version) because the kX drivers allow me to do crossover and don't cost money!

However, when I went to post the link to my sound card I saw that it supports ASIO 2. (I have been to that page several times and have no idea why I didn't see that before, lol..)

Anyway, it was probably premature for me to continue with the post since I'm still just weighing out my options in my head. Since I have though, I'll go ahead and think aloud..

-Since I now know my card supports ASIO, I can go ahead and look for a software solution to active crossover and see how much that would cost (I know there are programs listed in the sound tuning thread and that's where I'm headed in a sec)

-I can also see how much an original Audigy or Audigy 2 would cost me, since both of those are compatible with the kX drivers.

-I have a SB Live! Value card that I believe is compatible with the kX drivers, but I need to find out how many channels it has (the card is at my parents' house)

-I need to find out how the sound quality of the Audigy, Audigy 2, SB Live! Value, and Revo 7.1 compare so I can weigh the cost of each option against the SQ benefits each one will give me.

durwood

No problem.

If you want to use your REVo 7.1,

Then you can use Allocator Lite and Virtual audio cable.

FA lite = $60
VAC = $30-50 (depends on where you download it from i think)

The 31 band EQ = Free (depending on which one you use)
Winamp VST plugin bridge (for using 31 band EQ) = Free

Then later add in,
Console = $50 (Allows you to use multiple VST plugins such as the time delay below)
Voxengo Delays = Free (Time Delay for each driver)

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netchris

Well it looks like my SB Live! card doesn't have 5 channels, so that's out of the equation.

I've downloaded the Allocator Lite demo and have been playing around with it a bit. As I understand it, I should be able to load in VST plugins, but haven't yet gotten the 31 band VST EQ to load. As far as time delay, I haven't even thought about it. I'll have to look at CPU cost versus how much better my audio will actually sound.

It also looks like sticking with my Revo will be a bit more expensive than going the kX route. I assume the sound quality would be better if I stuck with my Revo, but how much better?

[edit]
You know what.. I just realized that the default Revo 7.1 driver control panel has options for crossover:

Think that's comparable to the crossover options offered by Frequency Allocator Lite?

[edit again]
Never mind.. the driver control panel offers only very limited crossover options that wouldn't be suited to an active setup.

durwood

1) YOu can;t load other vst plugins inside FA. FA can run by itself or you can load FA AND the 31 band EQ inside Console. Think of Console as where you can wire up all your plugins. It's a very powerful program. I think the VSTHost program you came accross can do it too but I haven't tested it.


Option 1:

Winamp => VST plugin BRIDGE => 31 band EQ
See here on how

Then you can use a combo of VAC with FA to do the crossover function

Option 2: (The route I am going)

Winamp
Directwire (Part of Audiotrak drivers) substitute VAC here
Console
(Connected inside Console) 2x 31 band EQ=>FA=>4x Stereo Voxengo Delays

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netchris

I did have eq31.dll loaded up inside the winamp VST bridge, but after some of this audio processing info started to sink in I realized that the FA .exe is actually just a very simple VST host program. I figured why not get a different VST host program and put all of my VST plugins in there so all audio can be routed through it. Enter VST Host!

[edit]


Why two 31 band EQs?

I have no idea how much the stereo voxengo delays will help me, but you know way more about audio processing than I do, so I went ahead and downloaded the plugin! :P I'm still a little confused why you have 4 of them though. I know you have a 3 way setup, so do you have 1 delay for subs, 1 for lows, 1 for mids, and 1 for tweets? I guess that means you're tuning the vertical delay but not the horizontal? (so it sounds the same to both driver and passenger) Is this like phase tuning? or is that something completely different..

[edit again]
d'oh! I am stupid -- just realized the plugin has separate delays for both left and right channels! I guess I'll need only 3 delays in my setup. I'm still wondering about the phase question though..

durwood

I wanted at least 2 (one for the left side and one for right) but it would also be really nice to have one for each speaker. I might go that route later but it gets very complicated. You really need an Real Time Audio Analyzer (RTA) to help out with that part. It would allow me to adjust each speaker independently to get a smoother frequency response.

Phase delay and time delay are similar in ways, but they affect the sound in much different ways. Phase changes at different frequencies. Time delay however allows you to delay the entire speaker so that the sound arrives at the listener at the same time from speakers at different distances. It allows you to place the sound stage in the correct position in your car. You are essentially "placing" the speaker at equal lengths from each other electronically rather than by path length equalization (Kick panels or horns). There are debates on this method though.

Also, with most crossovers, they introduce a phase delay at the crossover frequency. See my thread I started here but never finished. The Full version of FA corrects for this though even though it's not an FIR filter.

Actually you really only need 3 stereo delays. You really don't need one for you sub since it is usually the farthest speaker from you. If you need help understanding time delay, Alpine explains it very nicely in regards to Time Alignment on their headunits/H701 processor.

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durwood

Not sure what you mean by vertical vs horizontal but time delay makes your car sound really good from the seat you tune it from. It's what we call a one seat tuned car. Bad for your passengers but good for you If you want it to sound the same on both sides of the car, you have to go kick panels or horns. There are tradeoffs for both.

It won't sound horrible to your passenger, but it will sound like all the sound comes from the right side of the car to the passenger if you go the time delay route.

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netchris

So FA Lite doesn't correct phase? Does that mean FA Lite doesn't sound as good as the full FA?


I only have a 2 seat car and the engine is right behind me, so I'll have to put the sub right behind my seat unless I found some way to put it under the glove box, but i really don't know if that would be worth it. I'm definitely going to look up Alpine's explanation of this though.


When I wrote that I was wrongly thinking that you were tuning the tweets as a pair, mids as a pair, lows as a pair, etc.


I'll definitely give it a look since it wont cost me any money, haha. So far we've got EQ, crossover, and time delay. Are there any other types of audio processing that could increase SQ?

[edit]
There's probably something wrong with my reasoning here, but why couldn't we just make a hard cut band pass filter right at our crossover frequencies with no attenuation or dB slope at all? For example, 99Hz would come out of the sub at full volume, and 100Hz wouldn't come out of the sub at all.

Then we wouldn't have to worry about phase correction, right?

[yet another edit]
Something like this maybe? It's free...
http://www.madtracker.org/plugins.php?author=buzzroom

When searching for crossovers I didn't find much other than FA, but I'm finding a lot more when I search for band pass filters.. Hoping to find a FIR one, haha!

netchris

Ok well I found a FIR filter, so maybe this thing could be used for active crossover, but I'm not the expert here, sooo....

http://www.rekkerd.org/sweetboy-vst/ (it's listed as T-SLEDGE)

How much difference would FIR really make?

XC-C30

you might point and tune your tweeters to the center of your front window, right under your rearview mirror.... that way I think it will sound best for both driver and passenger.... It maybe won't sound as good as when you would locate the stage right infront of the driver, but this way the passenger also will have a fairly nice soundstage..... So unless you're competing, this -to me- seems the best option. Wether you go with on-axis or off-axis tweets, well, that's an other story, but you already know that, Durwood

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netchris

It wouldn't be best to point both tweeters right between the heads of the driver and passenger? Why would I point the tweets right below the rear view mirror? I never have my head there..

Abmolech

Have a read up of ambiphonics and crosstalk.

netchris

I'll definitely look into it! I was under the impression that on-axis listening was the best though, and I (maybe wrongly) assumed that on axis = pointing the speaker at your head?

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