SVS 20-39CS

Airplay355

Hey guys,

I picked up a used SVS 20-39CS today along with an Outlaw m200 monoblock (300wpc into 4ohm) to power it. I've got it setup from the LFE output, straight to the amp with my mains set to small and crossed at 80hz.

So far I'm disappointed. The output is far far less than I expected - I expected to need to find a way to turn it down and all instead I'm looking for ways to turn it up. It's just kind of OK. What's wrong?

I thought maybe the amp was not enough but it isn't even getting warm, it's completely cool. I thought if I were asking too much of it, it would start getting warm-hot. It's room temp on one side (cold feeling) and maybe 80F on the other, not cold but not body temp. The room isn't that big, maybe 13x15 with a hallway in the back. I changed out the electrical cord he was using as speaker wire and that helped a little but something still doesn't seem right.

I've tried using both my apple TV and macbook pro as a source. Neither made a difference. I expected hard punchy bass that would dig so deep I'd feel like I was waking up the neighborhood. I got something that was slightly better than my SDA2Bs. The driver isn't blown, it's not scratchy or anything, it's just not punchy or deep enough.

I thought 300wpc would be alright for this thing but do I need a monster pro amp to get work done?

Airplay355

I think you're right. I wasn't sure if the M200 would be enough but it was a pretty decent deal so I figured it would be a good place to start. I can find another use for it or sell it I guess.

Do you think I need something more like this amp on flea bay? http://www.ebay.com/itm/Crown-XLI2500-XLi-2500-Stereo-2-Channel-1500-Watt-Power-Amplifier-/311901919705?hash=item489ecd99d9:g:wQ0AAOSwKytZEg5i

This is my first passive subwoofer. It probably would have been easier to try to find an active one but this one was only 10min from me.

I haven't crawled around...might do that when the wife isn't around haha

Construction is suspended. HT is upstairs with an empty garage beneath it. So plenty of bounce.

hochpt21

I know it sounds stupid, but the crawl is real.

I did the sub crawl for my powered SVS and it sounded great.

A couple weeks later it almost sounded like it wasn't working.

I checked and my wife had moved it about 3 feet.

Moved it back and...bam-perfect.

The crawl is real.

txcoastal1

@ZLTFUL
One of these days Ryan, I must embark and imbibe, in one of your scheduled HT crawls. Seen many HT's but never as a GTG style event. Lightman also mentioned it was a great event to discuss cables

txcoastal1

I would never antagonize, but do like having a good time

....sorry for the de-rail.....carry on

Airplay355

So basically something like

1) https://www.parts-express.com/behringer-nu1000dsp-inuke-1000-watt-power-amplifier-with-dsp--248-6702

2) https://www.parts-express.com/behringer-nu3000dsp-inuke-3000-watt-power-amplifier-with-dsp--248-6706

3) https://www.parts-express.com/crown-xls-1002-drivecore-2-power-amplifier-2-x-350w-at-4-ohms--245-507

Are those behringer numbers even real? Do I even need that much? Seems like it might be overkill and that they maybe had to skimp with quality to get quantity. The crown looks like the nicer amp but has 1/3 of the power. Am I splitting hairs here?

EndersShadow

With the Behringer's you can set a limiter on the driver so you can decide what you think is a good number, use it there and then slowly increase the voltage limit till you get to where you think you've either got enough to make you happy, or are making the sub make noises.

You will also want to make sure you set a subsonic filter at or right below the port tune of the sub to make sure you dont blow it due to frequencies down super low causing it to go to far one way or the other.

As far as how much wattage is too much.... overhead is good, especially for short bursts....

I'm running a set of Crown XLS2000's all out on my sealed 18" subs and personally I would love to have 4 subs instead of 2.....

Airplay355

That is crazy

Airplay355

Sounds like I need one I'll use the monoblock to bi-amp the center or something.

Airplay355

What is that, a 9.6 system?

How bad is the fan noise? I don't have a good spot to hide noisy equipment. Unfortunately the closet that could work for hiding stuff is in the back and I don't want to have 20ft cable runs for everything.

Airplay355

So I've spent some more time with it and I think I can live with it for now after messing with some settings. I think more AMP is definitely the way to go but in the end I'll probably need more sub as well. These would probably be more fun as a pair

I watched the scene from GoT in Season 2 where they light the blackwater bay on fire. It was pretty awesome but some parts caused audible distortion. No bottoming but just some distortion. It could be from my source though, I don't have a lot of faith in this older Marantz AVR.

vmaxer

I had the powered version of this sub in a huge open room, pleanty of clean and clear bass. You seem to have an issue of some sort.

Airplay355

I agree, something doesn't seem right. The bass is certainly decent sounding but isn't earth shattering. I'm going to wait a bit, get the rest of my system together and then pick up a pro amp like Ryan suggested. The little monoblock seems to do fine for music but large explosions and such seem to tax it

hochpt21

Have you done the sub crawl yet?

I thought something was wrong with my sub also.

Airplay355

I will tomorrow I just got the outlaw amp and tomorrow a bunch of interconnects come so I can hook everything up. If the difference between the mono outlaw and a pro amp is similar to the difference between my receiver and the amp I just got...I need a bigger amp. I had no idea it could make such a difference.

Airplay355

Haven't updated in a while since I've been busy with the rest of the HT but I've here are some updates...

I decided to do a little digging and try to figure out what was making noise inside the subwoofer. It was too high pitched to sound like distortion, there wasn't any bottoming and it wasn't coming from the ports, definitely the driver area. I thought it was the windows vibrating at first but now I think it may have been the speaker wire going from the terminals to the VC. I changed it out with some stiffer stuff that should stay out of the way and not bounce around in there so much. I haven't heard anything since but I also haven't really tried pushing anything.

Speaking of the internal wiring, it was completely green/black with oxidation. It had to go, there wasn't any saving it.

Next problem, I think the previous owner greased the rubber surround with something I guess I can't be too disappointed as I got the sub for $150 but it's a little annoying. I wiped all the grease off with a damp microfiber cloth and heavily diluted dish soap. It all came off but the surround is a little chalky looking in some places. It's certainly not as smooth and black as any of the surrounds on my other speakers. Even the SDA2B I have still have perfectly smooth surrounds. I guess I should have checked for this before I bought it but still, at $150 for a CS Ultra, I don't think I did too poorly.

I read that this sub uses a nitrile surround so I'm hoping any apparent damage is purely superficial and the grease didn't damage things too much. Any advice on protecting the driver? I've read something called 303 aerospace protectant might be beneficial. I mostly just want to prevent the rubber from cracking. I could also be convinced to just leave it alone. The driver is already 13 years old so if I get a few years our of it, I can just reuse the enclosure with something similar.

When I bought this, I didn't quite realize the size of the driver inside. I thought it would be closer to the size of an SVS driver I've been hoarding for years. After I unscrewed the final screw holding it in place and 50lbs of sub came at me, I realized this tiny Outlaw monoblock I've got isn't going to cut it. I ordered a Crown XLS 1502 after doing a bit of reading. I know the Behringer amps seem very popular but I didn't want one of those because they don't have RCA inputs, the fans are loud and I don't want to mod them, and they look terrible. The Crown was $300 on the fleabay and I plan on trying to run it bridged first. If I find another used SVS I can add another and go back to two channel. Since the enclosure is tuned to 20hz anyway, I don't care much about a 20hz rolloff from the amp, if that's even a thing. Some people claim yes and others say they've tested and say no. Either way, the Crown seemed like the better choice for me.

DaveHo

Search for a recent post by, I think, Westmassguy. He mentioned what he uses to remove the brown oxidation from rubber surrounds. Might work for you.

EndersShadow

So you've got a small problem that I want to make sure your aware of.

1. Crown amps dont have a 20hz rolloff. I know, I have 2 and they are fine till about 10hz. If they did rolloff steep at 20hz it might actually help you.

2. You need a highpass filter somewhere below the tuning frequency of the port. Without this you WILL BLOW the driver. Frequencies in the low teens or below will cause the driver to bottom out and you will both hear it, and it will damage the driver.

#2 is why folks like the iNuke so much, it allows them to set a highpass for any manner of DIY ported subs, whereas the Crowns require an external device to do that before the signal gets to the amp. Your AVR will not have this ability.

Most plate amps already have built in 20hz highpass even though they dont state it, which again saves the drivers from harm.

Airplay355

I've got a little power box from SVS that came with the sub. It appears to have a HPF, gain and phase control. I haven't been using it because with the Outlaw, it seemed to decrease the output too much. However, with the Crown, I think I'll be alright. There will definitely be some experimenting involved. Help me understand what's going on though...why do I NEED to use this? Is it because of the enclosure tuning? Driver limitations? This is my first real sub and I really only know enough to get myself in trouble

Airplay355

I suppose another question should be, once I start using this filter, should I set it at 15 or 20hz? I suspect 20hz but just wanted to see what you thought.

EndersShadow

Airplay355 wrote: »

I've got a little power box from SVS that came with the sub. It appears to have a HPF, gain and phase control. I haven't been using it because with the Outlaw, it seemed to decrease the output too much. However, with the Crown, I think I'll be alright. There will definitely be some experimenting involved. Help me understand what's going on though...why do I NEED to use this? Is it because of the enclosure tuning? Driver limitations? This is my first real sub and I really only know enough to get myself in trouble.

Google subsonic filter for ported subs and get your read on. I wont go into it all, but that box keeps the driver from moving too far in one direction or another below the tuning point of the sub.

If you look at plate amps all the buttons are identical, except they normally dont have a highpass as its build in and not adjustable...

If it was a sealed box, no need, however you'd also be losing some serious output.

Airplay355 wrote: »

I suppose another question should be, once I start using this filter, should I set it at 15 or 20hz? I suspect 20hz but just wanted to see what you thought.

I'd try it at both but be careful to pay attention to how the driver sounds at loud volumes to make sure your not having issues.

vmaxer

Airplay355 wrote: »

Haven't updated in a while since I've been busy with the rest of the HT but I've here are some updates.

Next problem, I think the previous owner greased the rubber surround with something I guess I can't be too disappointed as I got the sub for $150 but it's a little annoying. I wiped all the grease off with a damp microfiber cloth and heavily diluted dish soap. It all came off but the surround is a little chalky looking in some places. It's certainly not as smooth and black as any of the surrounds on my other speakers. Even the SDA2B I have still have perfectly smooth surrounds. I guess I should have checked for this before I bought it but still, at $150 for a CS Ultra, I don't think I did too poorly.

I read that this sub uses a nitrile surround so I'm hoping any apparent damage is purely superficial and the grease didn't damage things too much. Any advice on protecting the driver? I've read something called 303 aerospace protectant might be beneficial. I mostly just want to prevent the rubber from cracking. I could also be convinced to just leave it alone

I work in automotive making plastic covers and rubber seals. The white discoloration is rubber bloom, a little about nitrile bloom can be found here:

http://www.hitechseals.com/includes/pdf/Rubber_bloom.pdf

Good luck.

Airplay355

Before I do anything stupid...can anyone confirm that the surround is some sort of nitrile? I can't find where I read that.

Airplay355

I never realized there was a model number sticker on the bottom. So I've got a CS Ultra model 0204-0480. The guy I bought it from gave me a PCi manual and I thought I was getting a CS+. Oh well He only told me it was a CS 20-39.

Here are some pictures of the driver.



What do you guys think?

ken brydson

Airplay355 wrote: »

I never realized there was a model number sticker on the bottom. So I've got a CS Ultra model 0204-0480. The guy I bought it from gave me a PCi manual and I thought I was getting a CS+. Oh well He only told me it was a CS 20-39.

Here are some pictures of the driver.



What do you guys think?

Call SVS. Their cs is excellent.

Airplay355

Good idea! I shot them the pictures and asked about treating the surround.

Airplay355

Alrighty the Crown came today. It's pretty awesome. I'm running it at 1'oclock with the preamp at -6db for the LFE. I put the HPF at 120 and have the mains LPF at 60 and surrounds/center at 80. This is off one channel. I'll try bridging it but I'm a little scared haha.

SVS got back to me and told me to Armor All the surround. I'm not so sure that's good advice. I'll keep looking for other options.

I'm still trying to dial in the sub by making sure I'm not clipping the signal. I initially had the gain higher but had to dial it back a good bit because bass heavy scenes would briefly clip. The lights on the front are very useful. I'm trying to set it up so that only the -20db light occasionally lights up. Do I need to tone it down to make sure these lights never light up?

I've only got streaming sources at the moment but it seems that Batman vs Superman on HBO Go has good enough quality audio to try setting this up.

I've still heard what sounds like distortion sometimes. Less so now that I dialed things back a good bit. Original settings were with the LFE at 0 and the gain around 4 o'clock. The subwoofer driver becomes audible (as in a vibrating frequency you can pinpoint) like something flapping in the wind. I suspect that I was just asking for too much SPL from a single 12" driver. I've never really had a subwoofer though so can you guys confirm I'm probably hearing distortion from the gain being too high?

Airplay355

I saw a few posts saying, run the amp wide open and adjust from your AVR/PRE. Well, they must be nuts. Cranking the knob off this thing is going to break something.

Airplay355

Forgot to mention, I set the amp to it's sensitive input setting. The outlaw has 2v preouts but I figured with the HPF inline, I would lose some voltage. The manual recommended using this setting when using RCA inputs.

Airplay355

I bridged the amp and that seemed to help with the impact and dynamics of the bass. Supposedly that's 1550 watts but who knows what's actually going to the sub since I've got the gain and trim low. I didn't have a problem with those aspects before but it feels better now.

I still don't get earth shattering, pants waffeling SPL but I think that's more of a subjective opinion rather than a fact. I also realize I've got a largish room. I never realized why people wanted 2, 3, 4 subwoofers in a room. And an IB setup, those people must be insane. Now I get it. I think I'll eventually try out an IB setup. With only $150 in the sub and $300 in an amp, I'd say this is working out pretty well though.

Airplay355

After watching game of thrones this weekend, I noticed some distortion when the dragon landed back in Dragonstone. Anyway, this annoyed me and led to some tinkering.

I took the driver out and noticed that there's high pitched noise that comes from the voicecoil below 35hz even at low db levels (less than 70). This can't be normal, right? The sub doesn't seem totally blown as I can't feel or hear any rubbing when I manually move the driver. Is this what bottoming sounds like?

When hooked up the way it should be, the driver moves in with more force than out. Is that because it's a ported sub? Reversing the polarity causes the driver to move outward with much more force (but no less squeaking).

I tried a smaller SVS driver I had laying around and it also squeaked a little in the low frequencies but it's equally as old so could be having the same problems. These drivers are 13 years old or so.