Modified SVS PB12-ISD: The Results Are In

Early B.

Here’s my preliminary assessment of the Atlas 12 vs. the SVS 12” ISD driver. The Atlas 12 from www.ascendantaudio.com cost $145 plus shipping and was shipped out the same day I ordered it and it arrived yesterday. Chad was very gracious in answering my questions and provided excellent customer service.

Upon inspection, the driver appears to be solidly made. It weighs in at a hefty 21 lbs. However, the SVS driver is no pushover. Both appear to be well made and of similar build quality. I can’t speak to anything beyond their appearance because I’m not familiar with the technical aspects of woofer design. Hell, I don’t really care. I’m simply interested in how they sound. So I removed the SVS driver from my PB12-ISD and installed the Atlas 12. Just took a few minutes to do it. No soldering is required. Both drivers use high quality metal spring terminals that look like 5-way binding posts. There are no instructions included in the box, so make sure you remember to add a jumper on the Atlas 12 (see website for details).

Alright, so I popped in my reference DVDs and listened critically for the bass. Here’s what I heard – there is a noticeable difference in sound quality between the two drivers. The Atlas 12 is more refined and controlled. In fact, the SVS actually sounds “boomy” compared to the Atlas. The Atlas 12 sounded more like a sealed sub. I had to turn the volume up a few clicks to compensate for the “tighter” sound.

At first, I was ambivalent about my new driver because it didn’t quite sound like what I was accustomed to hearing. But then I remembered going through this same feeling several times before. The first time was when I upgraded from a cheap Yamaha sub to the Hsu VTF-2. The Hsu obviously was a much better sub, but the difference in SQ took a day or two to get accustomed to. The second time was when I first heard my Lsi7’s and compared them to the RTi series. I didn’t realize the RTi’s were “bright” until I heard the 7’s. The third time was when I went from a ported sub (Hsu STF-2) to a sealed sub (Onix Rocket UFW-10) on my 2-channel system. Same thing. Had to get used to a slightly tighter bass. And finally, when I went from solid state to tubes, I didn’t realize SS was so “bright”. Now I seem to be going through this process again. But each time it has resulted in a better sound quality.

Final comments: the Atlas 12 is definitely a keeper. I would imagine that the Atlas 12 would make a much more dramatic difference with music than movies. I didn’t really test the new driver with music because I don’t listen to music on my HT system and my fronts dig down flat to 25 Hz anyway, so why bother?

I plan to sell my SVS driver and recoup most of my investment. So for a net cost of about $60 - $90, you can’t beat it. Hell, a decent pair of interconnects cost more than that. So I say you can add the Atlas 12 to your recommended buy list, especially if you’re into the DIY thing or, if you’re like me – someone who tries stuff out for the fun of it. For the DIYers, you can build a custom made HT sub using the Atlas 12 and know that your driver can produce better sound quality than a SVS’ 12” ISDs for less money.

dorokusai

Glad you had fun.

VR3

How is the extention?

Glad it worked out! (very cool)

PolkThug

Sounds like fun. I think that driver uses some technology that was developed for car subs so it should be pretty tough (but I could be wrong).

Early B.

OK, I got her really singing now. This morning I opened the enclosure back up, took out the cheap insulation and added acoustic foam. I also tweaked the crossover setting. I planned on upgrading the cheap wires from the amp to the driver, but decided to leave it alone for now. Popped in my test DVD and it sounded better than it did last night. In fact, when Darla taps on the aquarium, for a moment it seemed like we were inside the tank with the fish! Even my wife noticed the difference and said she's afraid of the sub. Gotta luv that.

PolkThug

Originally posted by Early B.
Even my wife noticed the difference and said she's afraid of the sub. Gotta luv that.

Glad to see you're putting the demo to good use torturing your wife!;)

Dr. Spec

Hi Early:

No suprise things sound different - that driver has different T/S parameters than the ISD, so it will react differently in the enclosure. And the EQ curve in the SVS amp may or may not be a good match for the Atlas woof.

Also that woofer has adjustable Qts - which setting did you use on the install - low medium or high? That can affect the overall FR, too.

Maybe running an FR sweep (RS meter, CFs, and sines) would be interesting and point out any differences you are hearing between the two drivers.

Also (not to be a wet blanket) but you might want to ask SVS about warranty issues you may have created by swapping the woof. It might be placing a load on the amp that was not originally intended or envisioned. I'd hate to see the amp smoke and then SVS tell you it's not covered or w/e.

Doc

Early B.

Also that woofer has adjustable Qts - which setting did you use on the install - low medium or high?

I used the low setting as recommended.

...you might want to ask SVS about warranty issues you may have created by swapping the woof. It might be placing a load on the amp that was not originally intended or envisioned. I'd hate to see the amp smoke and then SVS tell you it's not covered or w/e.

By changing out the driver, I've probably already violated the warranty. It's no longer an SVS sub. If something like that happened, I'd just buy another amp or sub. Besides, I guess it should be OK since the Atlas 12 is designed to perform at its maximum with only 250 watts. The SVS amp is 320 watts.

Maybe running an FR sweep (RS meter, CFs, and sines) would be interesting and point out any differences you are hearing between the two drivers.

I don't know **** about how to do that. Sounds a bit too techie for me.

VR3

Early...

When I ship your enclosure...

I'll include a CD with test tones, and I'll send you some correction factors through e-mail...

do you have excel and a RS meter?

Early B.

do you have excel and a RS meter?

Yep, but you'll have to tell me what to do and why.

VR3

I already have a spreadsheet filled out, you just have to punch numbers, Ill explain/send when the time comes...

goingganzo

i get the same thing i work in a pool so i under compreshon of water and in my ht it feels like i am in the tamk. the differance beteen the two subs is the new 12 has the xpl motor with greatley reduces thd till you get to stupid levels of excurson. i am debateing on how big to go on my upgrade. i was thinking of 2 18 avalanch ut i am thinkng of getting 3-4 and a qsc 3005 or 3405 to go with it. yeah that will rock the block

VR3

Ganzo...

Your HT is under a pool?

Do you make waves with some movies or what?

goingganzo

no0 i wokk at a pool and my sub is good enough to make you feel like you are in the tank for finding nemo.

Early B.

So I sold my old SVS driver for about $130 incl. shipping; paid approx. $160 shipped for the Atlas driver. So, in effect, I paid $30 to upgrade my sub. I'd say it was definitely money well spent.