A Guide to Subwoofers (Part II): Standing Waves & Room Modes

[HAMP]

Congrats on your new sub!!! Your signature looks different, did you get some new surrounds also?

[hsox05]

Originally Posted by HAMP

Congrats on your new sub!!! Your signature looks different, did you get some new surrounds also?

Thanks! Newegg had Polk 75ts on sale for 180 a piece so I went ahead and picked up a pair of those and moved everything else back a spot

From my understanding that'll be a moderate upgrade on the fronts over the monitor 70s... But the benefit is in the improved surround

[Big Daddy]

Originally Posted by hsox05

Question about the subcrawl. Is that a one spot fits all or when I get a new sub do I have to subcrawl again?

Reason I'm asking: right now I have a psw505. I ordered a PSA XV30 and am getting ready to rearrange my room. If I can use the Polk sub (which weighs about a quarter of the psa sub) it would be a lot easier, plus I can have the room setup the best way for when the monster actually arrives.

I'd much rather do the subcrawl with the psw than have to wait for the new one, if possible. But it the difference in the sub is going to cause a different sweet spot, I'll wait

The answer to your question is NO. The sub crawl may give you several locations that are optimal. You have to choose the location that is the most practical.

[Underdog Audio]

WOW! I must say your reputation certainly does precede you Big Daddy. I heard about you on the AVS Forum, but I ran into this post looking for the reasons why my dual subwoofer placement has fixed my issue with my bass. I had both of my subwoofers at the front of the room and was pretty disappointed with the frequency response I was getting in the very low end from like 35Hz to 20Hz. I had just moved into a house with a totally new room and it's kinda been a nightmare just trying to tame the modal ringing from my front speakers because they're so close to the wall. After I took care of that will some simple bass traps in the front corners of the room I found that all of my low bass was heard only in the back right corner of the room. I took one of my subwoofers and put it in the spot where I could hear all the bass and now I can hear bass that starts at 17Hz! Even though I was glad that I had remedied the problem, I wanted to know why. After reading your post it all makes sense now.

[tacanmj]

I'm curious to know if my set up is ideal for proper bass management. I would take any advice. I set the towers to large and Xover to 80. Reciever set to LFE+

[nikostis69]

Hello! This thread is really awesome!

I have added a sub recently to my PC audio setup in my room. The sound within the room is as I want it to be.

There is a side effect, though... Due to the room acting like a huge speaker cabinet, the LF exit the room to the rest of the house quite amplified.

Is there any way I can reduce this effect without affecting sound experience inside the room?

[Mike7300]

Originally Posted by tacanmj

I'm curious to know if my set up is ideal for proper bass management. I would take any advice. I set the towers to large and Xover to 80. Reciever set to LFE+

I could be wrong but i would think you want your towers set to small if you have a subwoofer hooked up so that the sub is handling the bass.

[ChromeJob]

Originally Posted by tacanmj

I'm curious to know if my set up is ideal for proper bass management. I would take any advice. I set the towers to large and Xover to 80. Reciever set to LFE+

Originally Posted by Mike7300

I could be wrong but i would think you want your towers set to small if you have a subwoofer hooked up so that the sub is handling the bass.

He's got his AVR set to "LFE+" which is sending bass to the sub and the mains.

This is a relatively uncontrolled duplication of bass creation, IMHO not "ideal for proper bass management." Set the mains to "small," set crossover to 80Hz or 100Hz (lower if your mains can handle low bass consistently and accurately), then turn LFE+ off. You can get test files at audiocheck.net to determine any nulls in your mains' response, etc. When set up well, I believe you should hear a nice smooth descending tone from all the speakers without a clear dip or boost anywhere near the cross over point.*

Originally Posted by nikostis69

Hello! This thread is really awesome!

I have added a sub recently to my PC audio setup in my room. The sound within the room is as I want it to be.

There is a side effect, though... Due to the room acting like a huge speaker cabinet, the LF exit the room to the rest of the house quite amplified.

Is there any way I can reduce this effect without affecting sound experience inside the room?

Your sub is clearly interacting with the structure. Try doing the "subwoofer crawl" (Google for it) and determine the ideal location for the sub, then place it there, tune it down so that it's blending in with the other speakers but not resonating with the walls. *

* There are several articles on how to do this stuff at audioholics.com. Some are old (8 years) but still relevant.

[tacanmj]

I have since done some AVR changes, according to opinion. And I have done a "crawl" to find null spots and found better homes for my subs. Thank you.

[Auditor55]

Originally Posted by tacanmj

I have since done some AVR changes, according to opinion. And I have done a "crawl" to find null spots and found better homes for my subs. Thank you.

The crawl test, in some rooms, is impractical. For example, how you going to lift up a PB13 Ultra and put in on your seating location and walk around the room.

Secondly, if you move the sub to one location to another, you're going to create a null in another location.

[pepcmac]

HI Big Daddy- I'm a high school teacher in SoCal and I think this kind of material should be taught in science and math classes. I'm working on some project-based learning units for Sound and Light and would love to use some of your work.

Could you PM me? I'd love to chat with you.

[GunZenBomZ]

Maybe get a Kundt's tube & show how sound makes standing waves.

[pepcmac]

Good idea!! I have a Rubens Tube, that's pretty hot, but I like the visual inside the Kundt tubes

[GunZenBomZ]

Nice'

[LordSummerIsle]

Several years in and my SVS PB2000 is still as strong as ever. I don't feel any need to upgrade from this model, though I would like to add a second one.

[GunZenBomZ]

I'm trying to get my fourth Jamo D7 subwoofer from a chap in Norway. Fingers crossed his advert isn't noticed by to many others..