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?

ZLTFUL

Honestly, the M200 isn't giving that sub the beans it needs so to speak.
The BASH amp that came on the powered version of that sub was 400 watts RMS with significantly higher burst rating.

I have the powered version and it does great on its own.

So some questions...

1. Suspended floor or stick on slab construction (concrete slab)? A concrete slab is amazing at sapping all of the LF energy from a sub.
2. Placement? Have you done a sub crawl? A sub crawl is where you put the sub as close to the main listening position as possible and then you crawl around the room until you find the place where the sub sounds the loudest and that will be the general area where you want the sub.

Bear in mind, a single sub gives you all kinds of issues to fight...room modes being the primary one. A sub crawl will help you get the sub close to where it needs to be but won't solve all the problems.

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.

ZLTFUL

That Crown is nice but spendy. For subs, I don't mind the Behringer iNukes (an NU3000 would be great for your application and allow you a second channel to add another sub down the road. But the iNukes have a reputation for fan noise under heavy use.

The Crown XLS1502 would also be a good option but is a deal more.

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

ZLTFUL

LOL...lots of naysayers in that world. But those of us who know, know we know.

You are welcome up here any time and we have plenty of great HTs in the area we can visit for an impromptu crawl.

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.....

ZLTFUL

The iNukes have been dynoed and shown to run about 75-80% of their advertised power.

Airplay355

That is crazy

ZLTFUL

There is a reason they are so popular with the DIY sub crowd.

Airplay355

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

ZLTFUL

I am currently running my front 3 JTR Triple 8s off of an NU4-6000 for my living room theater (temporary) until I finish my basement theater build.

Then my theater will be running off of:
Emotiva XPR-5 for front 3 and rear surrounds
1 NU4-6000 for the 2 rows of left and right surrounds
2x NU4-6000 for the 6 Stereo Integrity HT18D2 subs in 4cf sealed enclosures
2x NU1000 for the 4 Atmos overheads.

I am a fan of them and since they will be mounted in the rack in the storage/server room.
So the fan noise if any won't be any issue.

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.

ZLTFUL

7.2.4 technically but I will have:
Front: LCR
Side Surround: x2 rows for 4 side surrounds
Rear Surround: 1 set of rears
Atmos: 4 overheads
and 6 subs total

As for the fans, the one I have upstairs I fan modded...you can get 80mm Noctua fans from Amazon that make them virtually silent although it does void the warranties. But with the stock fan, from 12ft away it was barely an audible hiss under load and they never ramped up beyond that.

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?