DIY Subwoofer Risers

[crazyBLUE]

Originally Posted by bluseminole

That could be arranged.....

Man - you just had to see that , Didn't you !!!!!

[Big Daddy]

Originally Posted by bluseminole

This raises an interesting question, and if it belongs elsewhere maybe you can redirect me, but...

The recommendation according to your sticky (Guide to Subwoofers, Part II) is for identical subs in a multi-sub setup. But couldn't a different sub offer advantages, such as making up for the weaknesses of the first sub? If you duplicate subwoofers identically, the weaknesses of one will still be weaknesses with two of them. I understand that from an evenness standpoint, identical subs are the most predictable...because different models will interact with the room differently. But couldn't performance be enhanced with...i dunno, four subs that are 18" (for lowest freqs), 12" and 12" (for the "typical" bass freqs and two of them for evenness), and 8" for the accuracy and punch in "higher" bass freqs? These are random picks, but still. BD, As an owner of differing sub models in the same listening room, what are your impressions? Would you recommend identical subs or properly calibrated differing subs for a multisub setup if you had to choose?

There is no doubt that two or four subwoofers in a small home theater room perform better than one subwoofer. Recently, Audioholics did a test of two Axiom EP 400 and test them against a bigger and more expensive Axiom EP 600 and reached the conclusion that two quality smaller subs perform better than a single larger quality sub in a room.

In an ideal world, it is best to buy identical and high quality subs. That is what I did when I decided to buy two high quality and identical 12" Hsu cylindrical subwoofers over 10 years ago.

However, if you already have a low quality subwoofer, it is not to your advantage to buy an identical low quality subwoofer. Low quality subs are sometimes louder because they only are capable of producing higher frequency bass sound that human ears are more sensitive to. That is why many people are disappointed initially when they buy a better sub. Better subs have better low frequency extension and are deeper and more musical, but not necessarily louder.

In my case, I intentionally changed the drivers of the two Hsu subs with two high quality sub drivers from different manufacturers to see the effect. I also build a 15" DIY sub with a high quality driver and an amplifier that outputs 1,500-2,000 watts into a 4 ohm driver. My last bit of craziness was to buy a relatively inexpensive Acoustic Audio HD-SUB12 and replace its driver with an Elemental Designs driver used in their ED A2-300 subwoofers.

I had to spend a lot of time positioning and adjusting their levels. Almost every day, I tweak or change something because I am a crazy tweaker and enjoy this. I am lucky that I have a realtively big (20ft x 25ft) dedicated HT room and a very cooperative WAF.

Furthermore, not everyone has the knowledge, experience in dealing with subwoofers ( I bought my first sub over 30 years ago), and the patience to tweak subwofers' settings and their placement. It also helps that I have the Velodyne SMS subwoofer Equalizer/Analyzer and spend hours every few weeks adjusting and equalizing the subs so that I get a relaitively horizontal frequency response from the subs.

All four subs are on DIY risers that are approximately the same height. I also added Buttkicker's isolators to the bottom of the risers.

I adjusted the level of each sub independently by turning off the other three so that each one gives me exactly the same amount of output at my primary listening position. I measured their responses with an SPL meter.

After I finalized their positioning and settings, I ran Audyssey calibration program and then tweaked the subwoofers' bass response with the Velodyne equalizer/analyser.

I will summarize my impressions in the following:

• The two cylindrical Hsu subwoofers are the most musical subs in the room. They don't play bass. They sing it.
• The modified Hsu subwoofer with a 12" Titanic driver is bit louder and deeper while the modified Hsu subwoofer with a 12" Peerless Aluminum driver is tighter and has better transient response.
• The DIY subwoofer with 15" Titanic driver and mucho amplifier power is without a doubt the deepest and scariest sub in the room.
• The modified AA HD-SUB12 with a 12" ED driver is by far the loudest. The gain level on its back is less than 40%. This sub was the loudest even before modification. In fact, the previous driver had a few advantages over the the ED driver.

Everytime I tweak something (often), I have to go through calibration and equalizing.

[jerix]

Big daddy I observed the acceptance of the RISER in this forum. There are yet no negative comment on it. Everybody reported the benefits gained from this thing, although I also observed the differing designs that leads me to the question on whether or not there is really a formula that determines the correct height of a RISER in consideration of the other factors affecting the sound? I think science is at work here and there must be a way to know the effect to the sound as you raise or lower the sub.

[chemokidd]

I just wanted to say by me seeing peoples post on this thread & pics on here have really helped me! I made my riser over the weekend & I love it! I'm 19 & that was the first thing I have ever made haha seeing tips and feedback really helped..so thank u all

p.s. it has made my Klipsch sub 10 sound way better!

[Big Daddy]

Originally Posted by jerix

Big daddy I observed the acceptance of the RISER in this forum. There are yet no negative comment on it. Everybody reported the benefits gained from this thing, although I also observed the differing designs that leads me to the question on whether or not there is really a formula that determines the correct height of a RISER in consideration of the other factors affecting the sound? I think science is at work here and there must be a way to know the effect to the sound as you raise or lower the sub.

The science behind raising a subwoofer is explained in posts #2 and #3 in this thread. Go back and read them.

[jerix]

I am very sorry but thanks for the direction.

[liquidice]

Originally Posted by chemokidd

I just wanted to say by me seeing peoples post on this thread & pics on here have really helped me! I made my riser over the weekend & I love it! I'm 19 & that was the first thing I have ever made haha seeing tips and feedback really helped..so thank u all

p.s. it has made my Klipsch sub 10 sound way better!

please post pictures.

Crazy, nice work man. Definitely unique thus far...

[chemokidd]

Originally Posted by liquidice

please post pictures.

Crazy, nice work man. Definitely unique thus far...

sry for the 1st three pics were taken with my iPhone

https://www.blu-ray.com/community/ga...&folderid=2092

I'll be posting more soon of my whole room!

[Big Daddy]

Originally Posted by chemokidd

sry for the 1st three pics were taken with my iPhone

https://www.blu-ray.com/community/ga...&folderid=2092

Nice job. You are way ahead of me. It took me 30 years to get there and you are already there at 19. I am jealous.

[chemokidd]

Originally Posted by Big Daddy

Nice job. You are way ahead of me. It took me 30 years to get there and you are already there at 19. I am jealous.

lol thank u very much! haha it felt like it took me 30 years inside of lowes o gosh I was very lost until I talked to a guy in the wood department haha
I hope I get to where u r now in making things!

[crazyBLUE]

Originally Posted by liquidice

please post pictures.

Crazy, nice work man. Definitely unique thus far...

Thanks ice , It helped the 110 out quit A bit !!

[liquidice]

crazy, check your HT thread for a quote from Brett from ED about sub stacking. I have a feeling BD might comment as well.

chemo, if you ever want to part with your Zooey picture, let me know! Nice bedroom setup, and good deal on the riser. Experimentation is fun!

recommendation, try and get your surrounds speakers up above your head.

[crazyBLUE]

Originally Posted by liquidice

crazy, check your HT thread for a quote from Brett from ED about sub stacking. I have a feeling BD might comment as well.

chemo, if you ever want to part with your Zooey picture, let me know! Nice bedroom setup, and good deal on the riser. Experimentation is fun!

recommendation, try and get your surrounds speakers up above your head.

I am always ready & look forward to his input on everything !

[Big Daddy]

Originally Posted by crazyBLUE

I am always ready & look forward to his input on everything !

I posted this in your HT thread. I will repost it here for the benefit of others.

I agree with Brett from ED. The whole point of having multiple subs is not to create more output, although you can easily do that. The most important reason for using 2 or 4 subwoofers is to smooth out the effect of nasty standing waves so that you get more even and smoother bass across the room.

The behavior of subwoofers in a small home theater room was studied extensively at the National Research Council (NRC) in Canada and at Harmon International under the direction of Dr. Floyd Toole. At one time, they ran computer simulations with 5,000 subwoofers. CrazyBlue is drooling

They reached the conclusion that an even number of subwoofers is the best and that more than 4 subwoofers will not give you any additional and significant benefit.

If you use one subwoofer or 4 subwoofers, the total level of bass output should match the other speakers. That is the whole point of calibration. It is ok to have a variance of a couple of dB's, but when the bass level increases by 6dB, it will bury the sound from the other speakers. In addition, it may make you deaf in a short while.

Therefore, subwoofer stacking is not necessarily a good idea. You should put two subwoofers in the middle of the side walls or in the middle of the front and rear walls. A less desirable placement is the front two corners of the room, slightly away from the room boundaries.

In all cases, make sure the level of each subwoofer is adjusted on their backs so that each one gives you the same level of output at your main listening position. You do not want one subwoofer to overpower the other one. An SPL meter may be required. Remember that two identical subwoofers may give you different outputs because of their location and interaction with the boundaries.

Once all the levels are adjusted, do not change them and run the calibration program so that the total level of all subwoofers matches the output level of the other speakers. Moreover, the built-in calibration programs such as Audyssey perform some equalization on the bass frequencies. For a more complete subwoofer equalization, a dedicated equalizer/analyzer such as the Velodyne SMS may be required.

[chemokidd]

I thought the white foam was too ugly so I spray painted a piece of foam black & think it looks way better

liquidice thank u very much
Experimentation is very fun lol Ive had time to do things since ive gotten out of school haha! I am in love with Zooey Deschanel I will prob never part without it sry :/
I will try & move the speakers up thank u!

[crazyBLUE]

Originally Posted by chemokidd;2101259
I thought the white foam was too ugly so I spray painted a piece of foam black & think it looks way better :D

[B

liquidice[/B] thank u very much
Experimentation is very fun lol Ive had time to do things since ive gotten out of school haha! I am in love with Zooey Deschanel I will prob never part without it sry :/
I will try & move the speakers up thank u!

chemokidd , It look's much better now with the Black foam !
There is one thing I would like to suggest & that would be to cover the top with carpet if you can . It will help with the sound .

[Fors*]

Originally Posted by chemokidd

I thought the white foam was too ugly so I spray painted a piece of foam black & think it looks way better

liquidice thank u very much
Experimentation is very fun lol Ive had time to do things since ive gotten out of school haha! I am in love with Zooey Deschanel I will prob never part without it sry :/
I will try & move the speakers up thank u!

Looks real good chemo, I like the black look as well.

[chemokidd]

Originally Posted by crazyBLUE

chemokidd , It look's much better now with the Black foam !
There is one thing I would like to suggest & that would be to cover the top with carpet if you can . It will help with the sound .

thank u crazyBLUE & forsberg21!
I was wondering if/how carpet would help but I cant find a place to get it
do u know where I could?
& where did u get that awesome egg shell foam?!

[Fors*]

Originally Posted by chemokidd

thank u crazyBLUE & forsberg21!
I was wondering if/how carpet would help but I cant find a place to get it
do u know where I could?
& where did u get that awesome egg shell foam?!

You can got to Lowes/Home Depot and in their rug department, they have rolls of carpet that can be cut to size. Looks like you wouldn't need too big of a piece, maybe 1 1/2' X 1 1/2' to be on the safe side. Also, if you do add the carpet/rug, also add something to further dampen the platform of the sub before you put the carpet over it. Something similiar to the padding you used under the platform. Good luck!

[chemokidd]

Originally Posted by forsberg21

You can got to Lowes/Home Depot and in their rug department, they have rolls of carpet that can be cut to size. Looks like you wouldn't need too big of a piece, maybe 1 1/2' X 1 1/2' to be on the safe side. Also, if you do add the carpet/rug, also add something to further dampen the platform of the sub before you put the carpet over it. Something similiar to the padding you used under the platform. Good luck!

yea when I was getting the wood I asked 2 workers & they pointed me to that department but when I was over there I couldnt find anyone to help me so I gave up (plus the wood was starting to cut into my hand) lol
but I'll go back down there & check it out!