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Discussion Starter #1
Dear all,

I am a newcomer!
Just surf the forum and build my first sealed sub.
My config are
Dayton RSS390HF 15"
Behringer A500
Enclosure 20"x20"x24"

Some photos here
w w w.sjc.edu.hk/~cbosco/1a.jpg
w w w.sjc.edu.hk/~cbosco/2a.jpg
w w w.sjc.edu.hk/~cbosco/3a.jpg
w w w.sjc.edu.hk/~cbosco/4a.jpg

Anything i do will improve the performance,
should i buy a Oaudio 500W amp to replace Behringer?

Thanks all

Nuub Magkids.
 

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Discussion Starter #3
Hi Mike,

I built this sub for my HT purpose,
maybe i should try ported for HT, :p
but sealed is more easier to build with...

I recently own a 10" sub and I found that
the diy 15" sub cant create a fast and "punchy"
feeling, the amount of bass is adequate when i turn to
3 o'clock of A500 but the bass is quite "blurr"...

For example, when i'm playing U571,
I can hear lots of bass for the bomb but i cant distinguish
different stage of the bombing. the feeling is different from
those commercial sub.

Changing a subwofer plate amp will help my situation?
Is that my stuffing incorrect?
:help::help::help:

Cheers,
Magkids
 

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Mike,

yes ,sir, i believe bridging the amp cant
give more loading as A500 support 8Ohm only at bridging..

Magkids :blink::blink:
 

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What are your mains and other associated equipment? How did you calibrate the mains to the sub?

I'm guessing you've got about 4.25 of net air space in that cabinet at most. My WinISD model says 230 watts is enough to get you to Xmax at 20Hz. The OAudio's 500 watts would push you over, but the 390's probably got enough Xsus to handle it.

First, I would make sure you're calibrated properly so the sub isn't overpowering your mains. I would also turn the A500's gain to max. From looking at the manual, that would appear to set the gain to 28dB; your processor will then control the actual output of the amp/sub.

Do you have the capability to run REW? It's possible the 390 is exciting modes you're other subs were incapable of reaching.

-Brent
 

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Discussion Starter #7
What are your mains and other associated equipment? How did you calibrate the mains to the sub?
- my mains are jmlab 707 bookshelf, av amp is onkyo 806.
I have set my crossover frequency at 80Hz. All speakers set to small with audyssey set up.



I'm guessing you've got about 4.25 of net air space in that cabinet at most. My WinISD model says 230 watts is enough to get you to Xmax at 20Hz. The OAudio's 500 watts would push you over, but the 390's probably got enough Xsus to handle it.

First, I would make sure you're calibrated properly so the sub isn't overpowering your mains. I would also turn the A500's gain to max. From looking at the manual, that would appear to set the gain to 28dB; your processor will then control the actual output of the amp/sub.

-ok, i'll try to turn the a500 to max. i'm having +2db in amp setting when A500 is set to 3 o'clock.
Is it appropiate to tune all speakers to 75dB after audyssey setup?


Do you have the capability to run REW? It's possible the 390 is exciting modes you're other subs were incapable of reaching.

- I am just trying to handle REW, no results yet. what means of exciting mode? I operate only the 390..

Thanks Brent!
Magkids:flex::flex:
 

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1) I wouldn't put any money towards a different amp - that driver in a sealed enclosure can't handle very much power to begin with. That driver is known for clean sound, but its output capability as a single sealed isn't going to be all that impressive.

2) I would disable Audyssey or any other "automatic" settings or equalization. Sometimes those programs can do some really crazy things. Try calibrating manually and moving the sub around a bit while checking the response with RoomEQ Wizard. If you are having a little trouble with RoomEQ right now, just try moving the sub and listening to it in different locations. Because of the somewhat limited output capabilities of that driver, I would highly suggest corner placement.

3) A 10" commercial sub is very likley going to overemphasize the 35-60hz range and not really offer anything usable below 30hz, maybe 25hz if you're lucky. Also, the distortion will probably be a lot higher and you may be hearing harmonics that push up into higher frequencies, providing more artificial punch.
 

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Discussion Starter #10
oops..
my sub already takes up 2ft x 2 ft
i'm sure my mum will kill me if it getting larger.
Is it possible to modify the existing one to vented?

but i model it in winisd tells me 4 ft cu vented wont improve a lot for this driver.
 

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Magkids, what you're describing sounds like a lack of pitch definition to me. It's likely either caused by the 390 overpowering your mains or the 390 is exciting a room mode that your other sub could not. More output, either via a bigger amp or porting for more low end output, will not help this type of situation.

A room mode is a frequency, that do to the physical dimensions of the room, is overemphasized. You could also end up with a null, which is no or severely reduced level at certain frequencies. Running a sweep with REW will help you identify any problem frequencies. Room treatments and experiementing with sub and/or listening position can help compensate to some extent. Depending on which version of Audyssey you have, it may be able to improve the response a little bit...you can't really boost out of a null, but you can reduce a peak a bit.

The detail you're looking for in explosions really comes from the higher frequencies played by your mains. If you listen to content with just the sub, it's more of a thud-thud. For a simplistic example. The lowest note on a standard 4 string electric bass is 40ish Hz. It's the harmonics of an instrument that give the instrument its audio signature. So, if you play the lowest note on that bass, the first harmonic will be at 80ish Hz and reproduced by both the sub and mains about equally with an 80Hz crossover point. Obviously, the higher you go on that bass, the more of its signature comes from your mains while the fundamental frequency is played by the sub.

Did you run the Audyssey auto calibration routine or are you doing level calibration manually with an SPL meter? The auto routine usually does a good job of getting the levels matched, but room acoustics can sometimes throw them off. If doing it manually, you can really pick any arbitrary SPL to level all channels to, but it's commonly accepted to calibrate to 75/85dB depending on whether your test tones are recorded at -30/-20dBFS. The Onkyo x05 series, and likely other generations, internal tones are -30dBFS so 75dB would be the target. What receiver/version of Audyssey do you have? Some versions actually apply EQ to the sub channel, while some only adjust the level/distance.

I recommended turning up the amp because Behringer doesn't list a range for the gain structure as would be expected for an amp with variable gain. That suggests to me the "gain" knobs are really just attenuators. By running the A500 at full gain, you reduce the chance of overdriving one of the low level upstream preamp stages. FWIW, my sub channel ends up at something like -3/-4 and my sub amp has about the same gain (29dB) as the A500 is rated at (28dB). Even then, I'm running a little bit hotter than the auto routine suggested...room is 24x16x9 with the sub about 14' from the main listening position.

-Brent
 
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