DIY Subwoofer Risers

[Big Daddy]

DK,

Buy some foam from Wal-Mart and attach it with spray glue under the riser and cover it with carpet. It will dampen the riser better. For the ED sub, if you attack longer legs to the subwoofer, you may get better results. Look at the 4 inch legs I attached to my round Hsu subwoofers in Post #2. The difference in sound quality was noticeable.

[crazyBLUE]

They look great DK ! So how do they sound ! reviews please so other people don't think Big Daddy & I are

[Big Daddy]

Originally Posted by crazyBLUE

They look great DK ! So how do they sound ! reviews please so other people don't think Big Daddy & I are

He did his review in ED thread. It doesn't matter if DK reviews the risres or not. We are definitely crazy.

[Driver_King]

Originally Posted by Big Daddy

DK,

Buy some foam from Wal-Mart and attach it with spray glue under the riser and cover it with carpet. It will dampen the riser better. For the ED sub, if you attack longer legs to the subwoofer, you may get better results. Look at the 4 inch legs I attached to my round Hsu subwoofers in Post #2. The difference in sound quality was noticeable.

Where and what should I purchase the longer legs for the A2-300? Also, Walmart sells the Poly-fill foam for around $8.00. Is there a cheaper solution? I mean I have two pounds of Poly-fill already...

[Driver_King]

I added some new pics to my gallery too by the way. You may want to check them and their comments out (near the bottom of the gallery).

[Big Daddy]

Originally Posted by Driver_King

Where and what should I purchase the longer legs for the A2-300? Also, Walmart sells the Poly-fill foam for around $8.00. Is there a cheaper solution? I mean I have two pounds of Poly-fill already...

Parts Express sells better quality foam, but it is not that cheap.

1/2" Acoustic Foam or 1" Acoustic Foam.

The one from Wal-Mart is 15" x17" with a thickness of 2". You can try fabric stores or art and craft stores to see if you can find something cheaper.

You can buy the legs from Home Depot or Lowes. These are ready-made table legs. Ask someone in the store for table legs. They also sell installation plates for around $2 each.

[Driver_King]

I don't need to go hunting around for the cheapest price on foam. I just wanted to make sure I was looking at the right foam. At my local Walmart, the foam is located near the Poly-fill bags (same isle). Did your cost around $8 each? How many do you think I should get for both subs (if my DIY sub even needs it)? I am also wondering where I can find some more carpet samples and if Walmart sells the table legs as well. That would be nice to make one last trip to Walmart and be done (with this portion of the project at least). Thanks.

[Big Daddy]

Originally Posted by Driver_King

I don't need to go hunting around for the cheapest price on foam. I just wanted to make sure I was looking at the right foam. At my local Walmart, the foam is located near the Poly-fill bags (same isle). Did your cost around $8 each? How many do you think I should get for both subs (if my DIY sub even needs it)? I am also wondering where I can find some more carpet samples and if Walmart sells the table legs as well. That would be nice to make one last trip to Walmart and be done (with this portion of the project at least). Thanks.

You need at least two foams, one for each riser. I built 4 risers and bought 6 foams. They are $7 and some cents plus 8% sales tax here.

The only places that have carpet samples are Home Depot/Lowes and carpet specialty stores.

Table legs are only sold at hardware stores. The short ones (2" to 6") are from $2.50 to $6.50 each. Plain ones without any designs cost less.

I am currently working on diffusers to attach to the ceiling. I practically live in Home Depot. I am sure as soon as CrazyBlue finds out, he is going to start worrying about diffusers.

[Driver_King]

Sounds good BD!

[liquidice]

Originally Posted by Big Daddy

DK,

For the ED sub, if you attach longer legs to the subwoofer, you may get better results.

BD, when you mention adding these additional legs to the subs themselves, do you think they primarily help down firing subs as opposed to front firing?

crazyBLUE, I know you put additional legs on your front firing sub, but wondering exactly what kind of differences you noticed after doing so.

[crazyBLUE]

Originally Posted by liquidice

BD, when you mention adding these additional legs to the subs themselves, do you think they primarily help down firing subs as opposed to front firing?

crazyBLUE, I know you put additional legs on your front firing sub, but wondering exactly what kind of differences you noticed after doing so.

By raising my sub , It now sounds fuller ,stronger, & the muddyness has all disappeared . It sounds more like it should sound (natural) !!

[Big Daddy]

Originally Posted by liquidice

BD, when you mention adding these additional legs to the subs themselves, do you think they primarily help down firing subs as opposed to front firing?

crazyBLUE, I know you put additional legs on your front firing sub, but wondering exactly what kind of differences you noticed after doing so.

Front-firing and down-firing is something in our heads. Subwoofers and waves do not care. Waves are waves and go in every direction, particularly the long wavelengths of low frequency sound.

The biggest effect when you raise a subwoofer is that it may become a lot louder. You don't have to believe me or CrazyBlue. There is scientific reason behind this.

The sound waves interact with the room boundaries (walls, floor, and ceiling) and create standing waves or room modes. The standing waves are different between floor and ceiling, side walls, and end walls, unless any of these dimensions are the same (the worst kind of room is a perfect cube). There are three basic types of modes: axial, tangential, and oblique.

Low frequency wavelengths are much longer (e.g., 56.5ft at 20Hz, 22.6ft at 50Hz, and 11.3ft at 100Hz) than higher frequency wavelengths (e.g., 3.8ft at 300Hz, 1.1ft at 1,000Hz, and 1 inch at 13,000Hz). This is important, especially below 150hz or so. Above 150hz, the waves are small enough that they are not affected by the room size as much. They bounce around every which way. Standing waves only become a significant problem at lower frequencies (below 100 Hz) because we normally set the crossover frequency around 85Hz. Long wavelength bass frequencies travel back and forth bouncing off the walls.

Axial Modes are the strongest and the most important, and the easiest to compute. Tangential Modes are about half as loud, and Oblique Modes are about a quarter as loud. They tend to be the least important, but if an oblique room mode occurs near another mode, that frequency may still be a problem. It is best to calculate all room modes to see where any overlap may be.

The three types of AXIAL modes are LENGTH, WIDTH, and HEIGHT. Knowing the speed of sound and the wavelengths of different frequencies, we can easily calculate these three types of axial modes.

When you move a subwoofer around a room, you are basically trying to deal with horizontal axial resonance modes (length and width). Almost everybody discovers this and tries to deal with it. Unfortunately, the vast majority of people are not aware that subwoofers and waves do not understand horizontal or vertical. By raising a subwoofer, you are actually dealing with the vertical (height) resonance mode.

To fully understand this, be patient and read A Guide to Subwoofers (Part II): Standing Waves & Room Modes.

[liquidice]

thanks for the response, I have been through the awesome guide you put together, but realize I should go through it again.

[Slec]

I've been through the guide several times and still haven't picked it all up... in time.. in time..

[Big Daddy]

Originally Posted by liquidice

after resetting up on my GRAMPA, first reaction: bass seems much less with music, but then again, my system always seems to lack with music. Movie: seems a little less in output, not as loud. Gonna really have to seach out some deep-bass scenes in movies to give it a real test drive.

This has something to do with tuning.

If you want the subwoofer to be loud (SPL), you tune high (e.g., 40Hz). At high tuning the sound quality will not be very good. If you care more about sound quality, you tune fairly low (e.g., 25Hz). Lower tuned boxes sound more like sealed boxes.

What you experienced is not unusual. Poly-fill slightly lowers the tuning of the enclosure. This makes the bass sound a bit deeper (better quality) at the expense of SPL. It is a small change, not very drastic. You can always turn the volume up slightly to compensate.

[jomari]

this also improves the subs performance in handling the lower extensions as well. you've also eliminated any reflective points for your subwoofer, letting you hear the subwoofer instead of the corner that it was in. if i may assume, your sub was more 'boomy' sounding louder in that corner, appearing louder.

loud doesnt necessarily mean good.

Big Daddy, i hope you didnt mind me posting another thread. id hope you would consider my invite as well.

[Fors*]

I just loosely filled my cabinet as well with polly fill, and although the benefits I heard were minimal, I do sense a greater "tightness" with the lower db's. I also just completed risers for my sub (and both fronts as they are on ceramic tile) last night, and I think this has contributed to better AQ overall from my front soundstage as well. Pics of the risers I built are in my gallery (pics 1 and 2) and I listed the parts I used in the HT Construction thread if you want details. I took Big Daddy's advise and built my own.

I also was able to attach some black PVC piping to the bottom feet of the sub to further lift it up another 2-3 inches (look closely in pic #1).

Everything was cheap and easy to do!

[Big Daddy]

Originally Posted by forsberg21

I just loosely filled my cabinet as well with polly fill, and although the benefits I heard were minimal, I do sense a greater "tightness" with the lower db's. I also just completed risers for my sub (and both fronts as they are on ceramic tile) last night, and I think this has contributed to better AQ overall from my front soundstage as well. Pics of the risers I built are in my gallery (pics 1 and 2) and I listed the parts I used in the HT Construction thread if you want details. I took Big Daddy's advise and built my own.

I also was able to attach some black PVC piping to the bottom feet of the sub to further lift it up another 2-3 inches (look closely in pic #1).

Everything was cheap and easy to do!

Where are the pictures?

[Fors*]

Originally Posted by Big Daddy

Where are the pictures?

The pictures of the polly-fill going into the sub are on my cell phone, so they will look rather bad, but you are right, I should upload them. As far as the pictures for the risers being built, I was forced to do this outside (I had to cut the wood myself as Lowes' saw was out of order.... and my daughter and son were both inside and occupying my "space",) so by the time I got to work on it.......yes, I forgot.... It just got dark soo fast, that I wanted to get it done before their bedtime......uuggh kids! I do have a couple of pics in my gallery (pics #1 and 2), of the finished risers, but that's it......I apologize, but anyone with kids....you know how this happens....

[Big Daddy]

Originally Posted by forsberg21

The pictures of the polly-fill going into the sub are on my cell phone, so they will look rather bad, but you are right, I should upload them. As far as the pictures for the risers being built, I was forced to do this outside (I had to cut the wood myself as Lowes' saw was out of order.... and my daughter and son were both inside and occupying my "space",) so by the time I got to work on it.......yes, I forgot.... It just got dark soo fast, that I wanted to get it done before their bedtime......uuggh kids! I do have a couple of pics in my gallery (pics #1 and 2), of the finished risers, but that's it......I apologize, but anyone with kids....you know how this happens....

I have three grown children and sometimes they act worse than babies.