My DIY Sonosub is DONE!

tryrrthg

I finally finished my DIY sub. I bought the driver back in November and never had any extra cash or time to do anything with it until recently.

The sub sounds pretty good. I haven't had much time with her, but she is a step up from the predecessor (Polk PSW450).

The two problems I am having is that it doesn't seem to be playing as low as it should. Or maybe I just can't hear past 25hz, but it seems to be hitting brick wall after that, although I haven't really tested it fully to see, this was just from a few quick test tones. My design was supposed to be -3 dB's around 20 hz or so... Oh well, it still sounds pretty good.

The second "problem" is that I can localize the bass. Think it's mainly due to the pressure wave that it's creating in my little apartment. I can "sense" where the wave is coming from so that is kind of distracting. One things for sure, I'm definitely pissing off the neighbors!

A picture, you can see the "mini" PSW450 sitting next to the sonosub:


More construction and Misc. pictures.

RuSsMaN

Looking good, looking good!

How are the endcaps coupled to the tube? Other than the threaded rods, that is.

Cheers,
Russ

tryrrthg

Originally posted by RuSsMaN
Looking good, looking good!

How are the endcaps coupled to the tube? Other than the threaded rods, that is.

Cheers,
Russ

Thanks Russ!

Each 3/4" end cap has an MDF "plug" glued to it (the plug is the same inside diameter as the sonotube). The bottom plug is 1.5" and the top plug is 3/4". After plugging the tube with them I just caulked the seems to make sure no air leaks out.

gatemplin

Nice job Tryrrthg,

How are you going to cover it? What driver did you use? What are you using to power it? Volume, port length, etc, I want details and more pics!

I have found that if the sub is too close to the wall, the drywall will shake and you will be able to pinpoint the sub. Also make sure there are no air leaks around the driver, port etc. That could pe part of the output problem as well. I had a low (below 25 Hz) output and it turned out that the port volume was too large compared to the Vb. If you make a frequency response graph Doc can help you with the output problem.

tryrrthg

Originally posted by gatemplin
Nice job Tryrrthg,

How are you going to cover it? What driver did you use? What are you using to power it? Volume, port length, etc, I want details and more pics!

I have found that if the sub is too close to the wall, the drywall will shake and you will be able to pinpoint the sub. Also make sure there are no air leaks around the driver, port etc. That could pe part of the output problem as well. I had a low (below 25 Hz) output and it turned out that the port volume was too large compared to the Vb. If you make a frequency response graph Doc can help you with the output problem.

Thanks!

There is a link in my original post to more pictures. but here it is again

I plan to have my wife make a fabric "sock" to slide over it and cover the sonotube. I'll try to check out some of the things you suggested but being in an apartment I can't drive this thing to it's potential. My wife and I are in the middle of buying our first house so in a few months I'll be able to let her loose! The only other thing that I thought might be causing the localization is the sonotube vibrating...

The driver is an old SVS driver. It was their original driver before the ISD. It models VERY close to the Adire Shiva driver.

The sub is 114 liters tuned to around 20hz. 4" flared port 18" long. Using a 250 watt Parts Express sub amp that I got from scratch and dent for $90. It looks brand new to me!

gatemplin

Thanks for the details, I missed the link. That is a quality job. I threw the numbers into LSPcad (shiva specs) and everthing seems good. It is flat until the mid twenties and then gradually rolls off. F10 is in the mid-teens. You should be feeling the low bass but I guess you wont know until you do a frequency response graph. I think I will try and take some pics of my finished sub and frequency response also.

tryrrthg

I had a feeling I should be getting more output but I was only doing some quick test tones at pretty low volumes (60 dB's or lower) so the output probably was too low to even hear. I like it a lot reguardless. One day I'd like to put it in a box to see if the vibrating sonotube is causing the localization.

Thanks again for the compliments!

gmorris

Very cool...

I don't know if I'm missing something here, but I've always been told if you can localize the sub, the crossover setting is too high. Where is your crossover set? Did you try to lower it?

Also, where did you get that round tube? What is it exactly? What is it made of? It looks like cardboard.

PolkThug

Originally posted by tryrrthg
I can "sense" where the wave is coming from so that is kind of distracting.

Of course you can tell where it's coming from, even though low bass in non-directional, it still radiates from a single location (many people overlook this when the argue about whether bass is non-directional or not).

Sure, if you can get far enough away from your sub, you may not be able to tell exactly where its at, which is what people try to achieve, but I'm guessing your about 12 feet from it or less.

Basically, don't sweat it! You'll get used to it, and it will eventually stop bothering you.

Regards,
PolkThug

tryrrthg

Originally posted by gmorris
Very cool...

I don't know if I'm missing something here, but I've always been told if you can localize the sub, the crossover setting is too high. Where is your crossover set? Did you try to lower it?

Also, where did you get that round tube? What is it exactly? What is it made of? It looks like cardboard.

Thanks!

I've got my crossover set at 40hz (12 dB's per octave). so it's pretty low. I can't go any lower.

The round tube is sonotube. It's used for pouring concrete. It is cardboard but very rigid. A lot of people in the DIY sub community use it. Check this out

tryrrthg

Originally posted by PolkThug
Of course you can tell where it's coming from, even though low bass in non-directional, it still radiates from a single location (many people overlook this when the argue about whether bass is non-directional or not).

Sure, if you can get far enough away from your sub, you may not be able to tell exactly where its at, which is what people try to achieve, but I'm guessing your about 12 feet from it or less.

Basically, don't sweat it! You'll get used to it, and it will eventually stop bothering you.

Regards,
PolkThug

I'm probably only about 8 feet from the sub. our apartment is SMALL!

wlrandall

What program did you use, if any, for the design??

tryrrthg

WinISD Pro and an Excel based program called Unibox.

WinISD

Unibox

gmorris

one criticism,

the sonotube is upside down.... it would have been easier to read the writing if you had flipped it right side up....

anyway, when do you want to make that trip over to Progressive Audio?

tryrrthg

ha ha! yeah the tube is upside down but the bottom was a tighter fit for the plug with the driver. That's all getting covered up some day

anyway, when do you want to make that trip over to Progressive Audio?

Oh crap! I forgot all about that. We've been so busy trying to get a house bought. We just went into contract for a house just a couple miles down the street from Progressive. I'll see what I can do, but it's a crazy time right now.

My wife does work on saturday, maybe we can do it then. we'll see...

dorokusai

That looks great, hope your tuning gets squared away, and you start breaking things.

ken brydson

Originally posted by gmorris
one criticism,

the sonotube is upside down.... it would have been easier to read the writing if you had flipped it right side up....

I just turned my monitor upside down and I could read it just fine
Looks great and sounds like a fun project

tryrrthg

Originally posted by dorokusai
That looks great, hope your tuning gets squared away, and you start breaking things.

Thanks! I'll probably just start cramming some poly-fil in there if I'm not getting the extension I want.

My wife's exact words after my first demo "You better not break anything or I'll be really mad" mission accomplished

Dr. Spec

Nice work! DIY cylinder subs are cool.

Make sure the PE amp you bought doesn't have a built-in high pass filter at 25 or 20 Hz. Most of the PE's use an 18 Hz high pass IIRC, but maybe something is different with yours.

Easy way to tell is measure the amp output into a dummy load and drop the frequency; if the amp output starts to drop off quickly below a certain frequency, that's where your high pass is kicking in.

Consult with HBomb on this; he did the same thing to verify the high pass points on his SVS-01 Bass Box by Marchand Electronics. The filter points and the associated slopes were right on the bean.

Can't hurt to rule it out before you start blaming the sub or the design.

Doc

faster100

Not to derail, but Spec....... Did ya get that pb2 ultra yet???

Ok back on track

goingganzo

welcome to the wonderfull world of diy. and great looking sub. i bet you will want another soon to match matching subs is a must for the waf lol

tryrrthg

Originally posted by Dr. Spec
Nice work! DIY cylinder subs are cool.

Make sure the PE amp you bought doesn't have a built-in high pass filter at 25 or 20 Hz. Most of the PE's use an 18 Hz high pass IIRC, but maybe something is different with yours.

Easy way to tell is measure the amp output into a dummy load and drop the frequency; if the amp output starts to drop off quickly below a certain frequency, that's where your high pass is kicking in.

Consult with HBomb on this; he did the same thing to verify the high pass points on his SVS-01 Bass Box by Marchand Electronics. The filter points and the associated slopes were right on the bean.

Can't hurt to rule it out before you start blaming the sub or the design.

Doc

Thanks Doc!

I was told over at HTF DIY section that the rumble filter is around 19hz on the model that I have. I'll have to run some frequency sweeps sometime this weekend, if I can do it without pissing of the neighbors too much.

Someone over at HTF also mentioned that the slope on the crossover is only 12 dB's/octave so I'm still getting pretty decent output at 80hz and above (my crossover was at 40hz). So that could be the culprit also...

I did some listening with the new toy last night and was hearing some bass detail I'd never heard before. It was kind of spooky on some of the tracks.

tryrrthg

Originally posted by goingganzo
welcome to the wonderfull world of diy. and great looking sub. i bet you will want another soon to match matching subs is a must for the waf lol

Thanks! I think this is probably it for me for a while. Until I can convince the wife to let me go infinite baffle that is!

gidrah

Great stuff. I just wanted to say congratulations and job well done before I had to actually read this thread and ask all the questions I need to.

Dr. Spec

Good to know the high pass is set to 19 Hz (I'd still verify that, though).

If you run a sweep, do it "near-field" at 1 meter, and split the distance between the woofer and the port with the mic.

Near-field will really help minimize the affect of room acoustics and much more accurately reflect the true FR of the sub.

If you really want to get crazy, do it outside, away from any borders/walls. But near-field is usually good enough.

Ron-P

Very impressive tryrrthg.

I am dying to build another, but would have no where to really put it in the current HT room. Such a fun and enjoyable project, they are.

I'm starting to piece together a small HT set-up in the living room and will most likely build a 12" sonsub for that rig.


Peace Out~:D

tryrrthg

Originally posted by gidrah
Great stuff. I just wanted to say congratulations and job well done before I had to actually read this thread and ask all the questions I need to.

Thanks! appreciate the comments!

Originally posted by Dr. Spec
Good to know the high pass is set to 19 Hz (I'd still verify that, though).

If you run a sweep, do it "near-field" at 1 meter, and split the distance between the woofer and the port with the mic.

Near-field will really help minimize the affect of room acoustics and much more accurately reflect the true FR of the sub.

If you really want to get crazy, do it outside, away from any borders/walls. But near-field is usually good enough.

I'll try to do some near field and listening position sweeps this weekend.

can your RTA software be used with just a radio shack SPL meter or would I have to buy something special? Is there any RTA software that can just be used with the rat shack meter?

Originally posted by Ron-P
Very impressive tryrrthg.

I am dying to build another, but would have no where to really put it in the current HT room. Such a fun and enjoyable project, they are.

I'm starting to piece together a small HT set-up in the living room and will most likely build a 12" sonsub for that rig.

Thanks Ron! It really was a fun project. Although with all the circle's I cut I probably would try a box next time, would probably have cost me even less since the sonotube by the foot wasn't cheap...

With your garage set up you should consider going infinite baffle. Buy another tempest and you'd have more than enough output for your room.

Dr. Spec

can your RTA software be used with just a radio shack SPL meter or would I have to buy something special? Is there any RTA software that can just be used with the rat shack meter?

Yes, TrueRTA can be used with the RS meter. But you would need to still get the meter calibrated for correction factors. And the output from the meter tends to be high and also pretty distorted. People have tried the RS meter as a mic without much success.

The Behringer ECM8000 is a great measurement mic for the $$. Even out of the box, it's really flat. After professional calibration of the mic and preamp, and after automatic correction of the FR for the PC soundcard, the FR of my test rig is 10-25,000 Hz, +/- 1 dB or better.

The important thing to understand when using an amateur test rig like mine is that it has "clean limits" for the gain stages and for total sound pressure.

If I push a particular gain stage too far or overload the entire rig with too much sound pressure, it will start to introduce its own harmonic distortion.

It took me many hours of looping the entire rig (both with and without the mic) to determine the optimum settings for all the gain stages and find the overall pressure limits.

The pro-grade rigs and and high SPL mics (try $5,000 for starters) are certified "clean" up to around 160 dB, with extremely low noise floors too.

tryrrthg

Originally posted by Dr. Spec
Yes, TrueRTA can be used with the RS meter. But you would need to still get the meter calibrated for correction factors. And the output from the meter tends to be high and also pretty distorted. People have tried the RS meter as a mic without much success.

The Behringer ECM8000 is a great measurement mic for the $$. Even out of the box, it's really flat. After professional calibration of the mic and preamp, and after automatic correction of the FR for the PC soundcard, the FR of my test rig is 10-25,000 Hz, +/- 1 dB or better.

The important thing to understand when using an amateur test rig like mine is that it has "clean limits" for the gain stages and for total sound pressure.

If I push a particular gain stage too far or overload the entire rig with too much sound pressure, it will start to introduce its own harmonic distortion.

It took me many hours of looping the entire rig (both with and without the mic) to determine the optimum settings for all the gain stages and find the overall pressure limits.

The pro-grade rigs and and high SPL mics (try $5,000 for starters) are certified "clean" up to around 160 dB, with extremely low noise floors too.

Thanks for the info Doc. I'll have to look into that stuff in the future.

Originally posted by ATCVenom
Awesome project! How well does this sub blend in with your Dyns? Looks like it was fun and rewarding in the end! Good on ya.

Thanks! The sub blends in pretty well considering the lack of crossover slopes. I've got the x-over as low as it will go (40hz) and I'm running my Dyn's full range (they'll hit low 40's on their own). The slope on the sub amp is a little shallow so I'm still getting a little too much output above 40hz. I'd like it to slope off a bit quicker. Hopefully I'll be able to purchase a Paradigm X-30 crossover in the near future to give me more connection options and help with blending the sub a bit better for 2-channel listening.

del44

Good job! It's a very intimidating beast. BTW I've been to progressive audio. Pretty awesome place. Maybe the Wilson Grand Slamms are still for sale. Only $45,000 give or take. hehehe. Love the B&W room.

tryrrthg

Originally posted by del44
Good job! It's a very intimidating beast. BTW I've been to progressive audio. Pretty awesome place. Maybe the Wilson Grand Slamms are still for sale. Only $45,000 give or take. hehehe. Love the B&W room.

Thanks!

Last I was at Progressive they didn't even have the Grand Slamms hooked up. They were just sitting there doing nothing. They had the Wilson Watt Puppies running in their best room. Come to think of it the Grand Slamms have been sitting in the same spot for over a year and a half. They had some Avalon's running before the Watt Puppies. Loved those Avalons!