DIY Subwoofer Risers

[Grevlin]

I had friends over, and one wanted to sit in my seat. ! She is a good friend so I said sure. (hid the reluctance) I sat is a different spot and screamed "the bass sounds like s#it here!!" after about 30 minutes. I didn't scare anyone because they know me. I realized I ALWAYS sit in the sweet spot. I'm continuing to learn, and I'm now slowly trying to tweak the system. The desire for a new sub is creeping into my mind so I will probably be going to a 2-sub set up very soon.

[liquidice]

wow, another member whose setup I like so much. Never realized the DMB reference before. Gotta tell you, can't stop listening to "Why I Am" on my setup lately when I'm doing adjustments, or just want something awesome to listen to! Your room is so spacious, a second sub would do your theater some good. I also kind of feel that your current AA sub should be moved a little more to the corner, but obviously not wedged in the corner. Even just moved to the right of your right main speaker might make a difference. A second sub moved closer to your seated position might add beautiful bass throughout the whole room, therefore making every seat in the house a good one, for bass at least. Oh yeah, and your stand, looks an awful lot like mine, but maybe a little less wide? Where did you get it?

[Grevlin]

Oh yeah- its IKEA. I was going to buy a whole new console, but I was able to throw some pieces together that fit the bill.

DMB is my favorite band. I had problems when they lost Leroy.

I wish I could get a cool label like "Mad Scientist" I suppose mine would be something like "Opera Ghost" but I believe those labels are earned, not chosen. I'm seeing Phantom of the Opera for the first time on Tuesday and I'm able to get backstage after. If I can get an autograph from the Phantom it will have a main spot in my HT.

I'm in sub limbo at the moment. I love the HDSub, but I'm in need of something with more "scariness."

Thanks a bunch for the compliment. Its always a --Work-In-Progress--

[Big Daddy]

Originally Posted by Grevlin

I had friends over, and one wanted to sit in my seat. ! She is a good friend so I said sure. (hid the reluctance) I sat is a different spot and screamed "the bass sounds like s#it here!!" after about 30 minutes. I didn't scare anyone because they know me. I realized I ALWAYS sit in the sweet spot. I'm continuing to learn, and I'm now slowly trying to tweak the system. The desire for a new sub is creeping into my mind so I will probably be going to a 2-sub set up very soon.

My comments a couple of posts ago apply to many people. Because their subwoofers or their sofas are not in the best location, they tend to increase the level of the subwoofer and as a result put unnecessary pressure on it.

If you think your subwoofer is bottoming, the culprit is the level on the back of the sub or the gain inside the receiver. Currently, the levels on the back of my subwoofers are around the 40%. The gain in my receiver for the subs is -1.5dB. The bass sound in my room is loud, even, and enjoyable across he room. When I walk around with an SPL meter, the variation is no more than 3dB. Usually, a subwoofer is the loudest near the corners and walls.

In many years of owning different subwoofers from different manufacturers, I do not believe they have ever bottomed.

[Grevlin]

I may move my sub around tomorrow! My ocd will cause me much grief if I have to re-arrange for a new spot. But the sound comes before the look...

[liquidice]

there are still so many ways you can decorate your subwoofer into your suroundings with a certain function of decorative art. The sound does come first in all of our lives, otherwise, we might as well just toss the idea of home theater, and watch PBS with the tv speakers! You get the idea. You do need to put the 'sound' and 'PQ' first, otherwise your wasting your time on a home theater.

[Fors*]

Originally Posted by liquidice

there are still so many ways you can decorate your subwoofer into your suroundings with a certain function of decorative art. The sound does come first in all of our lives, otherwise, we might as well just toss the idea of home theater, and watch PBS with the tv speakers! You get the idea. You do need to put the 'sound' and 'PQ' first, otherwise your wasting your time on a home theater.

Or you could get a cylinder SVS sub and let it do the talking for you. As it is as much an amazing piece of art as it is in engineering. It's usually the first thing that someone sees and asks about when they enter my HT (even more so now that I built a riser for it, making it that much taller)...however, they have no clue what it actually is. So, I guess you could say that I got it to "blend" in with the surroundings, in an nice, aesthetic way!

[liquidice]

fors, where did you move your other sub too after getting the SVS? Love the riser man, very nice indeed.

[Fors*]

Originally Posted by liquidice

fors, where did you move your other sub too after getting the SVS? Love the riser man, very nice indeed.

Behind the couch on the left side of the room, facing in. The SVS of course is on the right side facing out. I still have the PSW10 on a riser, and I did use my SPL meter to dial it in from the new position. I have not had a ton of time to listen for any cancellations, but from what the SPL meter said at few locations I tested, the db levels varied around 3-4 db's from each location (reference being 75db's)....which I thought was acceptable.

Thanks for the compliment too ice!

[DBlackGT]

A riser will definitely help. However, you have to remember that the bass frequencies have long wavelengths and they interact with the room boundaries and create standing waves. As a result of these standing waves, you will have hot and cold spots across the room. If you put your subwoofer in a cold spot, you hear no bass. If you put your subwoofer in a hot spot, the bass will be too loud and tiring. For the same reason, if your seat is in a cold spot, you hear no bass and if your seat is in a hot spot, the bass will be too loud....

Big Daddy thank you very much for your response and suggestions. I figured that something like that was going on. In my last apartment I had basically the same setup, except my couch wasnt in the middle of the room it was against the opposite wall. And with that setup everything sounded great but now due to my current layout of my apartment, its just not possible. Im thinking maybe if I move my sub to the opposite corner where I hear the best bass it would be better. Im out of town now but when I get back on wednesday I will definitely experiment with that and raising it up. I hope you don't mind if I come back with several more questions.

[Drew664]

I've got a question about the quality of the sub vs these 'dead' spots that happen where the sound is just awful.

Let's assume that there is a room doing an A/B test with subwoofers. They set up subwoofer A, a low quality polk for example, and then they test for dead spots. Next they test subwoofer B, a Gotham for example, and they check for dead spots.

Would both these subwoofers have the same dead spots?

The overall point I'm trying to get at is if it's worth it to get 1 high quality sub or multiple lower quality ones. Let's assume that there will be multiple listening positions in a fairly large room.

[Fors*]

Originally Posted by Drew664

I've got a question about the quality of the sub vs these 'dead' spots that happen where the sound is just awful.

Let's assume that there is a room doing an A/B test with subwoofers. They set up subwoofer A, a low quality polk for example, and then they test for dead spots. Next they test subwoofer B, a Gotham for example, and they check for dead spots.

Would both these subwoofers have the same dead spots?

The overall point I'm trying to get at is if it's worth it to get 1 high quality sub or multiple lower quality ones. Let's assume that there will be multiple listening positions in a fairly large room.

This is right up Big Daddy's alley. If anyone can answer this in good detail, it would be him. Are you out there BD?

[Grevlin]

Originally Posted by forsberg21

This is right up Big Daddy's alley. If anyone can answer this in good detail, it would be him. Are you out there BD?

+1 Excellent question.

[aramis109]

Originally Posted by Drew664

I've got a question about the quality of the sub vs these 'dead' spots that happen where the sound is just awful.

Let's assume that there is a room doing an A/B test with subwoofers. They set up subwoofer A, a low quality polk for example, and then they test for dead spots. Next they test subwoofer B, a Gotham for example, and they check for dead spots.

Would both these subwoofers have the same dead spots?

The overall point I'm trying to get at is if it's worth it to get 1 high quality sub or multiple lower quality ones. Let's assume that there will be multiple listening positions in a fairly large room.

Personally, I would think not. I would think that they'll both suffer dead spots in similar areas, but with the better lower excursion, bigger box, better response and just more power that a Gotham would easily overcome problems that a Polk sub could not.

However, I'm interested in hearing from Da Mastah.

[potee]

I think I figured out how to send a pic. My first attempt at a riser. When company leaves I'll do an other one.

potee

[Aerodude73]

Originally Posted by potee

I think I figured out how to send a pic. My first attempt at a riser. When company leaves I'll do an other one.

potee

looks great! nice job

[liquidice]

if we put all of our risers together, we could build one of those cat playgrounds.



May I have your riser plzzz???

[erict]

BD next riser in the works.

1337114150_d10758f02e_m.jpg

[Big Daddy]

Originally Posted by Drew664

I've got a question about the quality of the sub vs these 'dead' spots that happen where the sound is just awful.

Let's assume that there is a room doing an A/B test with subwoofers. They set up subwoofer A, a low quality polk for example, and then they test for dead spots. Next they test subwoofer B, a Gotham for example, and they check for dead spots.

Would both these subwoofers have the same dead spots?

The overall point I'm trying to get at is if it's worth it to get 1 high quality sub or multiple lower quality ones. Let's assume that there will be multiple listening positions in a fairly large room.

Aramis is correct. The dead spots in the room do not have anything to do with the quality of the sub. It is pure Physics. It is the nature of the interaction beween the bass frequencies and the room boundaries. Expensive or low cost subs will have hot and cold spots. It depends on the location of the sub and the the way the room is shaped.

In almost all situations, two subwoofers are preferred to one. This has been proven in many tests at the National Research Council of Canada and at Harmon International. I believe Audioholics did a test between two Axiom EP400 and one Axiom EP600 and concluded that the two EP400's were better.

In 1998, I spent several hours with Dr. Hsu and discussed this topic with him and played around with different types of music. I ended up buying his two best subwoofers for around $1,550. Considereing that they were passive subs, they were pretty expensive. Hsu Research had expensive amplifiers for the subwoofers, but I didn't buy them because a few months earlier, I had spent $3,500 to buy the very powerful 6-channel Cinepro amplifier. I have used that amp to power the two subwoofers with excellent results. Recently, I added another 2 subwoofers to the room. The point I am making is that it is not the quality of the sub that creates the dead spots. When I run test tones and walk around the room, the variation in bass sound is no more than 3dB.

As a general rule, the bass sound is the loudest in the corners and next to the walls. It is the worst in the middle of the room. The only way you can get rid of this uneven sound is by using multiple subs and equalization. Tests have proven that it is best to use an even number of subwoofers up to 4. Even with 4 subwoofers, some equalization is necessary. I use the Velodyne SMS equalizer/analyzer.

[Fors*]

Now that is an impressive post! I did take some of this info to practice, as I use one very good sub and one not so good sub in my set-up. Then after auto-calibration with my SC-05 and using the SPL meter on my set-up and both subs, I walked around the room with my SPL meter and got a variance of 3-4 db's, so I feel that some, if any, bass voids must have been addressed. So that was good enough for me to leave them where they currently are. The SVS sub up is in the right front soundstage facing me, while the PSW10 is behind my couch (primary seating position) on the left side (opposite side from the SVS sub) facing in at the front soundstage.