Do I need an EQ for my sub?

B Run

So I recently picked up a SVS 16-46 cs+ with a 400watt crown pro audio amp. I notice sometimes in movies it can bottom out if it's cranked up, so I started reading about what I should do. Basically what i got is i'm lacking a subsonic filter to keep out the frequencies that are too low. The more I read the more I convinced myself that I need a parametric equalizer, like the Behringer Feedback Destroyer and download the REW software with it. I really don't want to invest in anymore gear or projects right now and this is all way over my head. I just don't want to damage my subwoofer either. Does anyone have any advice on if I need this, or if there's a cheaper or easier way to go? What about selling the crown and buying a better subwoofer amplifier with this stuff built in? I have a feeling this is going to cost some $ either way, just wanted some advice. Thanks guys.

quadzilla

Depends... you may just need to calibrated the level properly. The powered version of that sub comes with a 525 watt amp, so unless you're running that crown bridged, it's not likely that you're overpowering the sub.

B Run

I'm running it bridged, but i'm not concerned with overpowering it. The amp on the powered version has a subsonic filter and mine does not. That's my main concern, and then the more I dove into it, it seemed easier to buy an eq with a high pass filter to prevent damaging my driver. I just didn't know if there was an easier way to protect it.

quadzilla

If you run that crown bridged, it's likely to be delivering something north of 1000 watts. That sub wasn't built for that kind of power. And that's probably why you're bottoming it. So... try running off just one channel and set the level properly, then see if you still need any eq/filter.

thsmith

Room EQ Wizard aka REW at hometheatershack.com. You need something to see how your room and sub work together.

REW will help you best locate your sub to raise dips and then measure what peaks need to be filtered.

REW is free just need a RS SPL meter and sound card with real MIC in.

Great folks over there to help you along plus great documentation.

Once you get the hang of it its pretty easy.

The BFD1124 from Guitar Center is about $100 and can clip those peaks.

B Run

It's a crown com tech 400. It says 475 bridged into 8ohms but doesn't give a bridged rms for 4ohms, does that mean it's not 4ohm stable in bridge mode? It's 275 wpc with both channels driven at 4ohms, that doesn't seem like enough?
I signed up at home theater shack today and spent about 2 hours reading about the BFD1124 and the REW software. I'm just trying to avoid spending another $200 by the time I buy the BFD, a good SPL meter, and my mac doesn't have a sound card with real MIC in. I really just want some way to add a cheap high pass filter to cutoff frequencies below 15hz or so.

B Run

I also have the amp gain turned down and used MCACC to properly calibrate the sub level, it's at -10.5 right now and blends well with the system. Its just occasionally during movies it'll hit a crazy low frequency and start to bottom out. I usually watch my movies at around -10 on my pioneer and didn't think it seemed too loud. I appreciate all the help guys, just never had a passive sub/pro amp combo before and it's a little more difficult than my 505's were.
I also looked at the ed eQ.2 for $100 even though it's only 2 band, but they're sold out and hard to find, same thing with the old SVS subsonic filter.

aboroth00

What's your room size, where do you have it placed and where do you sit?

quadzilla

B Run wrote: »

It's a crown com tech 400. It says 475 bridged into 8ohms but doesn't give a bridged rms for 4ohms, does that mean it's not 4ohm stable in bridge mode? It's 275 wpc with both channels driven at 4ohms, that doesn't seem like enough?
I signed up at home theater shack today and spent about 2 hours reading about the BFD1124 and the REW software. I'm just trying to avoid spending another $200 by the time I buy the BFD, a good SPL meter, and my mac doesn't have a sound card with real MIC in. I really just want some way to add a cheap high pass filter to cutoff frequencies below 15hz or so.

Unless that amp is stable to 2 Ohms, it is not OK to run it bridged into 4 Ohm. Looking at http://www.crownaudio.com/pdf/legacy/ct00qref.pdf, it shows a "parallel mono" into 4 Ohms rating. And it does not look like it was designed to be run bridged into 4 Ohms. Also, the fact that power output barely increases when you go from 8 to 4 Ohms says that amp will struggle at 4 Ohms, and isn't like to be very stable. So it may be that what you're hearing is not the woofer bottoming out, but the amp struggling to power it.

Also, for what it's worth, most modern amps, including pro amps, have a built in subsonic filter built in that filters out frequencies below 10 Hz.

Try running it off just one channel for a bit and see what happens.

B Run

aboroth00 wrote: »

What's your room size, where do you have it placed and where do you sit?

My room is 24' wide and 22' long, I have it in the front right corner of the room and I sit on the first row couch about 10 feet from my tv.

Good to know on the amp, thanks for the advice Quad. I'll try just running one channel for a while and see how that works out. If it's not enough it might be time to buy a new amp.

thsmith

Take measurements and level set to your mains. You will be shocked.

People just don't get how important it is the measure their sub and eq it then run AVR eq.

AVR's just don't cut it with sub and their EQ.

If not you are leaving a lot on the table with sound level and quality.

You have been informed now do something about it.

B Run

thsmith wrote: »

Take measurements and level set to your mains. You will be shocked.

People just don't get how important it is the measure their sub and eq it then run AVR eq.

AVR's just don't cut it with sub and their EQ.

If not you are leaving a lot on the table with sound level and quality.

You have been informed now do something about it.

I'm informed and definitely going to fix this. So should I buy a radio shack SPL meter and manually calibrate it using the test tones on my avr? I'm still trying to find a good eq for a good price too, after hearing nothing but good things there's no going back.

aboroth00

The best thing to do is to calibrate levels with your primary source. Most people use DVE and Avia. These discs are invaluable for setting up a HT. It is almost mandatory for EVERYONE interested in HT to have a calibration disc and some sort of measuring equipment (radioshack SPL meter).

From what you've posted you're about in the middle of your room. This is absolutely the worst place to sit in a room. There is a null in the middle of any room sucking out the bass. So what youc ould be doing is overdriving your sub trying to compensate out the null you're sitting in. It would be recommended to then situate yourself further back, preferrably 2/3 of the room length.

Have you tried playing around with your sub placement? It is true for the most SPL, it's best to place it in a corner, but which corner is the best, that's for you to find out.

thsmith

SInce you live in AUstin I have a Turtle Beach sound card, RS SPL and cables.

All you need is a PC that will work with this sound card, external USB. Looking at the manual it is for Windows PCs and I believe you said you have a MAC.

www.turtlebeach.com/support/index.php?View=file&EntryID=396

I would be willing to send you the stuff but you need a laptop or pc running windows.

Trying to take manual measurements with SPL and track the results will be time consuming and drive you nuts. I tried that method first and decided my time learning REW was better spent.

Next time I am down in AUstin I could bring the gear but I am not sure when that would be. Probably talke an hour. At least then you would have some graphs to look at showing you the peaks you need to clip. If nothing else you could find best spot for sub.

B Run

thsmith wrote: »

SInce you live in AUstin I have a Turtle Beach sound card, RS SPL and cables.

All you need is a PC that will work with this sound card, external USB. Looking at the manual it is for Windows PCs and I believe you said you have a MAC.

www.turtlebeach.com/support/index.php?View=file&EntryID=396

I would be willing to send you the stuff but you need a laptop or pc running windows.

Trying to take manual measurements with SPL and track the results will be time consuming and drive you nuts. I tried that method first and decided my time learning REW was better spent.

Next time I am down in AUstin I could bring the gear but I am not sure when that would be. Probably talke an hour. At least then you would have some graphs to look at showing you the peaks you need to clip. If nothing else you could find best spot for sub.

Wow man that would be awesome. Just let me know next time you make it down this way, i'll gladly supply some beer and food. I really appreciate all the help, i'm just always trying to get the most out of my system and feel like without properly equalizing the sub i'm missing out. Thanks again.