Is SVS PB2000 an upgrade to these DIY subs?

[rojo]

Any luck Sylar? I played a bit with ASIO drivers a long time ago, attempting to hack a way to measure in the time domain using a USB mic. Ultimately, I decided my efforts were futile, and found a used XLR mic on the HTS forums classifieds for time domain measurements.

With that in mind, I don't think there's any benefit to using ASIO instead of the native sound device, regardless of whether you're measuring with a UMIK-1 or a Behringer ECM8000. If your PC is connected to your AVR via HDMI, just use the native driver, choose channel 4 for the subwoofer channel, and simplify your life.

 

[Sylar]

Any luck Sylar? I played a bit with ASIO drivers a long time ago, attempting to hack a way to measure in the time domain using a USB mic. Ultimately, I decided my efforts were futile, and found a used XLR mic on the HTS forums classifieds for time domain measurements.

With that in mind, I don't think there's any benefit to using ASIO instead of the native sound device, regardless of whether you're measuring with a UMIK-1 or a Behringer ECM8000. If your PC is connected to your AVR via HDMI, just use the native driver, choose channel 4 for the subwoofer channel, and simplify your life.

ahhhh....missed your post since it was first post on Page 2.

I been breaking my head with ASIO in the last couple of days. Have decided to dump the darn ASIO drivers and use java.
1. Is this (Java drivers) what you meant by native drivers?.

2. Also, What did you mean by, Choose channel 4 for the subwoofer channel.
Choose where?

3. I was able to get a few sample snapshots using Java. Would it suffice if i generate readings in the range of below 200Hz or should I go for the entire audio spectrum?

 

[rojo]

1. Yes, I meant Java REW driver.

2. I was mistaken. I forgot that installing ASIO gave me the ability to choose individual HDMI audio channels -- 1 for left front, 2 for right front, 3 for center, 4 for sub, etc. That functionality doesn't appear to be available while using the Java driver + default Windows output device. I guess I do use ASIO after all. Sorry about that. It's been a while since I've messed with this stuff.

3. Below 200Hz is perfect.

By the way, there's a cat named AustinJerry over at AVS who maintains a very nice intro to REW. There's a section in that guide that explains a bit about ASIO. It might help you.

 

[Sylar]

By the way, there's a cat named AustinJerry over at AVS who maintains a very nice intro to REW. There's a section in that guide that explains a bit about ASIO. It might help you.

I'm using the same guide for reference. Unfortunately, when you run into problems with ASIO...there is no reliable info on how to fix.
I have a couple of laptops. I'll give em a shot. If it still doesn't work the ill use Java.

 

[Sylar]

I took a few measurements (used Java). Hope I got it right.
Sub and fronts were used.

 

[rojo]

Looks like you've got a massive room null at 40Hz. Looks like the better part of an octave that's 10 - 20dB below the mean.

Have you tried playing with different placements, doing the subwoofer crawl, and maybe varying the phase on one of the subs?

 

[Sylar]

I dont think I have the option to tune the phase. Using XLS 1500.

I had done the sub crawl long back. I could try it again. I have 2 subs btw.

 

[rojo]

You could try wiring one of the subs up backwards and see what happens. If worse or no improvement, you can put it back the way it was and no harm done.

Sent from my LG-VS980 using Forum Fiend v1.3.1.

 

[lsiberian]

Allright, I'm going with Eq first since I already have a MiniDsp and a UMM6.

I'm Attempting to do some measurements using REW along with ASIO drivers, and facing some issues (I'm not able to hear the damn sweep signal) - trying to figure out whats wrong.
Will post the measurements once I am able to successfully measure.

You gotta hook the subs amp up directly to the signal. Before Eqing be sure to try different sub locations first.

 

[Sylar]

You could try wiring one of the subs up backwards and see what happens. If worse or no improvement, you can put it back the way it was and no harm done.

I took a bunch of measurements with the 2 subs in different corners. Also wired subs backwards. (I only tried the corners). Audyssey was off.
Here are the measurements.

Naming Conventions that I used
FL - Front Left
FR - Front Right
...
FRev - Front Polarity Reversed
BRev - Back Polarity Reversed
...

You gotta hook the subs amp up directly to the signal. Before Eqing be sure to try different sub locations first.

Didnt get that.
My sub amp is hooked to receiver sub pre-outs.

 

[Sylar]

Trying to figure out how to read the measurements. Correct me if I am wrong. Here is what I figured out.

1. Goal is to equalize to mean (I have Audyssey and MiniDSP, which can do that using DSP).
2. An amp with more headroom is great to have. If Frequencies below mean are to be amplified without issues, we would require a "capable" amp.
3. Peaks are fine since it can be attenuated towards mean.
4. Nulls are bad since they need to be amplified to mean. Larger the null the more it needs to be amplified. Which is a heavier load on the amp. Amp better have lots of head room.
5. High Average values below the mean is also not good since, on an average the amp needs to make up for the below mean values.
6. All of this is on top of the "normal" amplification process which by itself is a lot of work for the amp.


a. This was all about amplitude. What about phase? I see numerous phase shifts in the graphs.
b. Reproducing Lower frequencies require more power to amplify as compared to higher. Given a sub and an amp which is reproducing below 100Hz frequencies. Does it mean for them to reproduce a 30-40 Hz signals requires more power than a 90-100Hz signal?

 

[rojo]

I took a bunch of measurements with the 2 subs in different corners. Also wired subs backwards. (I only tried the corners). Audyssey was off.
Here are the measurements.

Naming Conventions that I used
FL - Front Left
FR - Front Right
...
FRev - Front Polarity Reversed
BRev - Back Polarity Reversed
...


Didnt get that.
My sub amp is hooked to receiver sub pre-outs.

Which configuration sounded best to you? From what I see, BL BR appears to require the fewest corrections, with FL BL a close second. You should try running Audyssey in one of those configs and see whether you end up with an improved sound. Or if you're running a MiniDSP, try correcting each sub in one of those configs, then re-running Audyssey.

The basis of this opinion is that, after smoothing to 1/12 octave (ctrl-shift-7 in REW), there are fewer skinny peaks (requiring high Q corrections), and both configs appeared to preserve the room gain below 40Hz.

It appears that switching the phase of one of the subs had little effect, in any case. Well, it was worth a shot.

 

[rojo]

[quote uid=54338 name="Sylar" post=1081989]Trying to figure out how to read the measurements. Correct me if I am wrong. Here is what I figured out.

1. Goal is to equalize to mean (I have Audyssey and MiniDSP, which can do that using DSP).
2. An amp with more headroom is great to have. If Frequencies below mean are to be amplified without issues, we would require a "capable" amp.
3. Peaks are fine since it can be attenuated towards mean.
4. Nulls are bad since they need to be amplified to mean. Larger the null the more it needs to be amplified. Which is a heavier load on the amp. Amp better have lots of head room.
5. High Average values below the mean is also not good since, on an average the amp needs to make up for the below mean values.
6. All of this is on top of the "normal" amplification process which by itself is a lot of work for the amp.


a. This was all about amplitude. What about phase? I see numerous phase shifts in the graphs.
b. Reproducing Lower frequencies require more power to amplify as compared to higher. Given a sub and an amp which is reproducing below 100Hz frequencies. Does it mean for them to reproduce a 30-40 Hz signals requires more power than a 90-100Hz signal?[/QUOTE]

These answers are leaving the realm of firm fact and delving into speculation. This is my understanding, be it sensible or ostensible.

1. Well, not necessarily mean. You can equalize below mean if it results in a flatter response. It's easier to cut than to boost.
2. Referring back to #1, the advantage of a stronger amp is that you can cut more, then add gain back to get back to normal volume. That doesn't mean your subs still have a normal work load though. They may consume less power in some frequences, and more in others.
3. Sharp peaks require high Q corrections. It's easier to correct a mound than a spike.
4. If there's room cancellation going on, there's not much you can do to boost those nulls other than try to reposition your subs to deal with them. Again, it's easier to cut than to boost.
5-6. Sorry, you lost me. Brain overloaded.

a. Varying the phase can help deal with cancellations between two subs. On the other hand, measured variances in phases aren't a big deal in the sub-bass range. As I understand it, it's more of an issue in the midrange, where the ears pick up on phase to help with aural location.
b. Yep. The cone has to be moved physically farther.

 

[Sylar]

Which configuration sounded best to you? From what I see, BL BR appears to require the fewest corrections, with FL BL a close second. You should try running Audyssey in one of those configs and see whether you end up with an improved sound. Or if you're running a MiniDSP, try correcting each sub in one of those configs, then re-running Audyssey.

The basis of this opinion is that, after smoothing to 1/12 octave (ctrl-shift-7 in REW), there are fewer skinny peaks (requiring high Q corrections), and both configs appeared to preserve the room gain below 40Hz.

I didn't do a listening test. Everything was purely measurements.
Will probably run with BL BR. Subs are in a convenient position. Will eq using MiniDSP and Audyssey and post the results. My first time trying to use MiniDSP.

I presume I should use MiniDSP first then Audessey since MiniDSP is the superior DSP among the 2.

Thanks for the answers. That helped to get a fairely decent idea.

 

[rojo]

If you sit closer to your rear sub than the front one, add 1ms delay to the rear per foot difference. For example, if your rear sub is 6 feet away and your front sub is 11 feet, set the delay on your rear sub to 5ms within your minidsp. I think that's how it works anyway. It's been a while since I messed with time aligning my subs.

Anyway, having your subs time and volume aligned and each as flat as possible before running Audyssey makes Audyssey work as though it were only correcting one sub. That's why you do miniDSP before Audyssey, not because one is better than the other. If your receiver has Audyssey XT32 with SubEQ HT, then it might make more sense to run Audyssey before correcting with miniDSP. But since Audyssey without SubEQ HT only provides LFE correction for a single receiver output, you'll get the best results from Audyssey if you get your subs as unified as possible with miniDSP first.

Sent from my LG-VS980 using Forum Fiend v1.3.1.

 

[rojo]

I'm curious to know the results. After repositioning and re-correcting, are you still shopping for new subs?

Sent from my LG-VS980 using Forum Fiend v1.3.1.

 

[Sylar]

I'm curious to know the results. After repositioning and re-correcting, are you still shopping for new subs?

Not yet. I have the MiniDSP but not the plugin. I had purchased long back, didn't download the plugin. So have contacted MiniDSP support. Havent heard from them yet. Waiting on them for now.

I did some listening with the subs in BL BR position. The sub sounds better for sure! I can feel my legs tingle with some music, which never happened before. It still about 5-15dB less than what I'd like. I really have to push the knob on my amp to 90% for music.

I am not shopping for sure. I might build another one. I definitely want a more powerful sub. I can get dayton & peerless drivers and they don't cost much.

One of my current subs rattles. I know it is coming from the drivers (both drivers of 1 sub). Its quite easily audible. Not sure what the issue is. is the driver gone?

 

[rojo]

The 18-inch Dayton RSS460HO-4 driver would make an excellent project.

Regarding rattle, I'm sorry but I couldn't tell you. It could be something simple to fix, like the dust cap on one of the drivers needing to be re-glued, or one of the wires inside the box vibrated loose. Or it could be something more sinister. Hard to say.

Sent from my LG-VS980 using Forum Fiend v1.3.1.

 

[Sylar]

18 i don't think so. It gets really big. Output from 15 should be loud enough, right?
18 is 100bucks more. I can get 2 of either 12's or the 14's instead.

Anyway, I can figure out whats wrong with the driver?

 

[rojo]

Might be worth starting a new thread if no one has any suggestions. I replaced the foam surrounds on my car subs once, but otherwise don't know enough about rebuilding drivers to be much help.

I think Parts-Express sells a Dayton 18" HO kit with a 3 cubic foot knockdown box. (Edit: It's 4 cubic feet. Sorry about that.) It wouldn't have to be much bigger than what you have now. Would you prefer sealed or ported? If ported I think you'd need a 200 liter box, if I recall correctly. TLS Guy would be a great person to ask to model something for you, or I can try to model something quick and dirty with WinISD tomorrow if you wish.

Sent from my LG-VS980 using Forum Fiend v1.3.1.