New subwoofer project started

[jason str]

Thank you for the kind words, a few weekends ago i moved the system into the living room when i had a few friends over for some partying and tunes, having the stereo in the larger room with the subwoofer properly positioned really let us enjoy some of the capabilities of the system.

Using my big Adcom GFA 5500 to power up the LaScala's we started to throw down some power but soon it was obvious i would need to dial down the volume because the house and everything in it rattled to no end, the frequencies also needed to be tamed because the CD player would just skip through songs but after some fine tuning everything went ok.

A couple pics with me behind the camera.

[Donnie27]

Thank you for the kind words, a few weekends ago i moved the system into the living room when i had a few friends over for some partying and tunes, having the stereo in the larger room with the subwoofer properly positioned really let us enjoy some of the capabilities of the system.

Using my big Adcom GFA 5500 to power up the LaScala's we started to throw down some power but soon it was obvious i would need to dial down the volume because the house and everything in it rattled to no end, the frequencies also needed to be tamed because the CD player would just skip through songs but after some fine tuning everything went ok.

A couple pics with me behind the camera.

Must have been killer, would have loved to have been there

[Donnie27]

Thank you for the kind words, a few weekends ago i moved the system into the living room when i had a few friends over for some partying and tunes, having the stereo in the larger room with the subwoofer properly positioned really let us enjoy some of the capabilities of the system.

Using my big Adcom GFA 5500 to power up the LaScala's we started to throw down some power but soon it was obvious i would need to dial down the volume because the house and everything in it rattled to no end, the frequencies also needed to be tamed because the CD player would just skip through songs but after some fine tuning everything went ok.

A couple pics with me behind the camera.

Bumping this thread because I'm getting ready to do me one on a slightly smaller Scale.

[Donnie27]

Thank you for the kind words, a few weekends ago i moved the system into the living room when i had a few friends over for some partying and tunes, having the stereo in the larger room with the subwoofer properly positioned really let us enjoy some of the capabilities of the system.

Using my big Adcom GFA 5500 to power up the LaScala's we started to throw down some power but soon it was obvious i would need to dial down the volume because the house and everything in it rattled to no end, the frequencies also needed to be tamed because the CD player would just skip through songs but after some fine tuning everything went ok.

A couple pics with me behind the camera.

For info's sake!

Also, you should have told me about the Dayton PlateAmp's, noise, Hum or Ground Feedback. I have to use a Ground Loop Isolator.

http://www.parts-express.com/pe/show...number=265-012
http://www.buy.com/prod/metra-gl15-g.../90147543.html

The one I got from Radio Shack was $12. They work perfectly. I get Zero noise and the amp turns off and on as it should. The only Amp I like better than this one is the 500 watt version of it. The 1000 watt version is a Joke if it is not meant for a large area outside. Or if you've already destroyed your hearing.

[stgdz]

Ground loop isolators cut the signal so you will loose output in that region that the hum is occuring, the PE plate amp is noisy as hell. You can bypass this with a cheater plug like I did for awhile but I didn't want to worry about the dangers with it in case the ground wire in the amp ever got disconnected. I ended up getting a behringer A500 amp and I don't have any noise what so ever.



Tuba's are great because they are cheap to build and you trade off space for output. The design rolls off a cliff at 20hz though so you will barely get anything below 20hz.

[jason str]

For info's sake!

Also, you should have told me about the Dayton PlateAmp's, noise, Hum or Ground Feedback. I have to use a Ground Loop Isolator.

Its not the amp's fault, something from your system is causing the noise.
Probably a bad cable or ground issue.

Tuba's are great because they are cheap to build and you trade off space for output. The design rolls off a cliff at 20hz though so you will barely get anything below 20hz.

I can easily shake the house with a 10 hz note, barely any output below 20 hz is slightly stretching the truth.

[stgdz]

I can easily shake the house with a 10 hz note, barely any output below 20 hz is slightly stretching the truth.

its all in the room gain though, mine and most others roll off at 20hz.



but as you can see my room is unfinished since I put all the important stuff, gear, first. I bet those lascala's sound great. Amazing how people are finally moving back to horn's and seeing the gains of high efficiency drivers after all these years of skinny speakers.

[Donnie27]

Its not the amp's fault, something from your system is causing the noise.
Probably a bad cable or ground issue.

I can easily shake the house with a 10 hz note, barely any output below 20 hz is slightly stretching the truth.

I agree about the rumble shake low Hz and not sure about the 20Hz roll off. I can however easily say the AMP is at fault. Not a bad cable or the location. I tried it out in the my Garage where NOTHING could cause the noise. See below?

Reply to both posts!

Ground loop isolators cut the signal so you will loose output in that region that the hum is occuring, the PE plate amp is noisy as hell. You can bypass this with a cheater plug like I did for awhile but I didn't want to worry about the dangers with it in case the ground wire in the amp ever got disconnected. I ended up getting a behringer A500 amp and I don't have any noise what so ever.

image

Tuba's are great because they are cheap to build and you trade off space for output. The design rolls off a cliff at 20hz though so you will barely get anything below 20hz.

Only the Sub's amp was Generating Noise. At one time I had four Subs and a Bass Guitar AMP. Both the Dayton AMP and Behringer create Hum or ground noise. Both are very sensitive and or wired wrong=P

Behringer BX4500H Ultrabass Bass Amplifier Head (450 Watts)
None of the other 3 Subs had any kind of noise, hum, or etc......... The others are a JBL SB120 12 500 Watt unit (now where the other DIY amp use to be), a cheap underrated 10" KLH and a Polk Audio PSW505 (recently sold for more than I paid for it). Also, none of the 3 sets of Computer speaker subs created or generated any kind of back ground noise like then Dayton in the same locations or any of the 4 four areas I tried it. I still have two of the Computer subs as well, a Creative 650 and a Logitech 560Z.

OK, now that that's out of the way. My Isolator has virtually no affect on my Sub and I did direct A vs B with the back ground noise and without. Only the Hum disappeared (60Hz range if I had to guesstimate). If some small insignificant frequency or Volume was lost, I couldn't tell. All of my system is Crossed over at 70Hz or set at the Receiver (Pioneer 819) and Sound Card, X-Fi Prelude, DIYer Mains, and Optimus Mach One's on the rear for now. If I needed to, I could Cross it over at 60Hz to make sure nothing is left out.

[breathemetal]

I gott ask. What was the total cost of it all?

[STEvil]

$50-$200 depending on what you have on hand

[breathemetal]

$50-$200 depending on what you have on hand

Id like to build my own sometime soon.
But i really have no experience.
My uncle is really good with wood so i may have him help me.
Any good guides?

[STEvil]

The simplest "well tuned" enclosure to build is usually a transmission line (t-line). They are based on quarter wave theory and are literally a single long port that maintains (for basic designs) the same size internally from the beginning to the end.

-First to build a T-line you take the speed of sound (1130 feet per second) and divide that by 4 (quarter wave).
-Second you choose what frequency you would like to tune the line to. Many people tune to the Fs of their driver, but you dont need to do this in reality. For a basic example i'll use 30hz.
-Third step is to divide 282.5 (quarter wave) by your desired tuning frequency to calculate the length of the line.
-Fourth you need to measure your subwoofer's cone area (sd). TTr^2. The correct measurement method if your specs are not availabe is from the center of the surround on one side to the other. For a 10" driver this is usually 9" or so. This number tells you what the internal cross-section of the line should be. For example with 63" of surface area for the driver you will need to make the line something like 5" x 12.6" internally.
-The last step is to fold your enclosure efficiently.. its the tricky part

For folding examples "Forevrbumpn" has a few examples (with his guide which mine is probably about identical to) here: http://www.stevemeadedesigns.com/boa...orial-updated/

1130/4 = 282.5.
Tuning Frequency: 30hz
Line length = 282.5/30 = 9.417 feet
sd = TT x 4.5^2 = 63.585 square inches

Now for some tips and tricks.

Depending on the excursion capabilities of your subwoofer you can make the t-line internal area a bit "small" to maintain driver control.
Power wise they dont need a lot, at all. They are very efficient.
If you want to tune your line "high" to save space you can flare the end of the line like a horn to still manage the low tuning and even increase effective active area when corner or wall loading the unit. As to the best flare rate.. the longer the better, just like a horn.
When you build the enclosure it is a good idea to round or "45" all internal corners for better aerodynamics.

If you want to read about horns here's a start (lol). Rocketscience gives some good basic info on mouth size relating to effective resonance of the line/horn.

http://ldsg.snippets.org/HORNS/design.html
http://en.wikipedia.org/wiki/Horn_loudspeaker
http://www.rocketsciencecanada.com/r..._SizeShape.asp
calc too: http://www.sonicdesign.se/horncalc.html

read the wiki first, it will scare you less lol

[breathemetal]

Wow...

Thanks a ton!
Thats a lot of info