Parts Express sub-amp bass boost
I'm sure a lot of you have seen the 250 watt amp at parts express that has a 6db bass boost at 30hz? For sealed enclosures, good idea or not? I think you should be safe using a lot of eq with a sealed box but 6db seems like a lot more work for the amp. WIth computer modeling most of the drivers I could find had an f3 around 40hz and -6db at 30hz.
Even for rap, I like sealed boxes because they have that extra kick and punch and not just a simple boring boom (and for someone who's never built one of these things before sealed boxes seem like a safe place to start)
Even for rap, I like sealed boxes because they have that extra kick and punch and not just a simple boring boom (and for someone who's never built one of these things before sealed boxes seem like a safe place to start)
Post edited by rs159 on
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Also, is 250 watt RMS or peak?
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What drivers are you looking at? I think you can easily by-pass the boost, read up in the PE forums.
Sealed box for ANY type of music as far as I'm concerned. It's a tough design to get right, and is also inherently MUCH less efficient (requiring more clean power), but done right, the notes start and stop on a dime. Not to mention from -3db and down, you have a very gradual (useable) response, unlike ported designs that tend to drop like Niagra Falls at 3-6db down.
The waterfall reference is a moot point with some of the drivers available today (VERY low F3 points, and sub-sonic repsonse when tuned [vented] properly), but I still hold it as a general rule. I'd rather have a properly designed sealed, or passive radiator, over ported, any day of the week.
250 Rms or peak? Neither actually, the correct term would be '250 continuous watts', you cannot actually have RMS 'watts', even though it has become a term we are used to.
Cheers,
Rooster
Check your lips at the door woman. Shake your hips like battleships. Yeah, all the white girls trip when I sing at Sunday service. -
RMS is easier to type :cool:
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When you think about it, even car stereo people like tight bass. I hear and see "It hits hard" a lot more than "It goes boom"
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Originally posted by RuSsMaN
What drivers are you looking at? I think you can easily by-pass the boost, read up in the PE forums...
Driver : Morel MW1075
Vas : 6.286
Qts : 0.65
Fs : 25.00
SPL : 89.00
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Project by : Mr. X
Project for : Mr. Y
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Number of drivers : 1
Box type : Closed
Box size : 8.000 ft^3
Relative
Freq Gain SPL
[Hz] [dB] [dB]
20.00 -8.42 93.57
25.00 -4.77 97.22
30.00 -2.32 99.68
35.00 -0.84 101.15
40.00 -0.06 101.94
45.00 0.32 102.31
50.00 0.48 102.48
55.00 0.53 102.53
60.00 0.53 102.53
65.00 0.51 102.50
70.00 0.48 102.47
75.00 0.44 102.44
80.00 0.40 102.40
85.00 0.37 102.37
90.00 0.34 102.34
95.00 0.31 102.31
100.00 0.29 102.28
Looks good for sealed, and without accounting for room gain (the room is 3900 cub. feet), and I will be building two of these guys and using them as subs -and- to compliment the midbass of the smaller RTi38s that will be up front. SPL levels are calculated at 9 feet with 150 watts (the actual operating conditions)
I'm new at this so any constructive critisism is welcomed. -
I bought the PE amp that does NOT have the bass boost (300-794).. it is actually cheaper. They had a special with no shipping so I got mine to my door for $120.
It came with a tech sheet on how to replace (I think two)resistors to put the boost at anything from 1 to 6dB. I assume I could do it on mine and add bass boost, or you could do it on one *with* bass boost and change the level.
I would have considered the bass boost model had the boost been defeatable and/or variable. As it is, I hopefully shouldn't need the boost anyway! -
Originally posted by burdette
I would have considered the bass boost model had the boost been defeatable and/or variable. As it is, I hopefully shouldn't need the boost anyway!
On paper, the response (SPL-wise) starts to go to hell around 30hz. By the time it hits 20 it's down 8.4db. (The f10 is ~18hz BTW) Then again, that's on paper and not in room. If I'm the crazy audio perfectionist I think I am then I might just HAVE to give it 2db of boost before the response goes to hell. Only one way to find out...
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Thats a fine driver, and two, room loaded.... should sound GREAT, esp on music.
Take lots of pics, we all want to see how your project progresses.
Cheers,
RoosterCheck your lips at the door woman. Shake your hips like battleships. Yeah, all the white girls trip when I sing at Sunday service. -
Originally posted by RuSsMaN
Thats a fine driver, and two, room loaded.... should sound GREAT, esp on music...
Great, that's what I was going for. I'm not much of a movie guy, really. I like some rap, but not at stupidly loud volumes.Originally posted by RuSsMaN
...Take lots of pics, we all want to see how your project progresses.
Cheers,
Rooster
Will do There's some MDF laying around from a garage renovation that I can use. With this driver and the 250 watt amp from PE (which is really 150 into 8ohms), and the wood allready avalible I should stay well within the $300 budget. I will be building two identical boxes, this is just the first. There will be a PSW 202 in the back too (Don't be quick to call me a basshead, I just want a system that can take anything I can throw at it. I don't think bass is non locatable until it's well under 40hz, hence my need for stereo subs and a back sub) -
Originally posted by RuSsMaN
...Take lots of pics, we all want to see how your project progresses.
Cheers,
Rooster
Ok then, here's the first. Using 8bit textures - that's why it looks so terrible. BTW, this rendering isn't final. The lighting is bad, and the speakers float in mid air, so needless to say I'm not done yet.
