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Old 17th September 2012, 05:47 AM   #11
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Quote:
Originally Posted by bobbobobbo View Post
Will leave filter off. Should I leave off indefinitely? If not, 30hz or 50hz?

Polyfill will reduce output? Assuming I cut the port down, polyfill lined should make the enclosure a bit larger, helping overall? If still tuned to 38hz. Or not worth it.
Most of your questions have been answered, but use the 30 Hz filter, the 50 Hz will cut too much.
Polyfill definitely will reduce output in the sub range (30-120 Hz), and LTD02 is correct, in your undersized box, the difference between your actual tuning of 33.5 and 38 does not amount to much.
Attached LTD02's sims and Peavey's actual cabinet response curves for comparison.
If you want to get low bass in a 5 cube cab, a pair of speakers like the Lab 12 or TC Epic 12 will kill the Low rider. But you already have built a too small cabinet for your 18", so solly.
Turbodawg's bracing suggestions are valid, surprisingly bracing affects the upper "kick" sub range (around 80-160 Hz) more than the bottom octaves.
If you jam a divider (or two) in the port (use some paintable black caulk for sealant) it will help bracing and also make the port a bit more effective.
As somebody else mentioned, multiple ports also allow for "step down" (Electro-Voice term) operation by plugging a port the tuning goes down.
Attached Images
File Type: png Low Rider.png (66.2 KB, 112 views)
File Type: png Picture 1.png (100.3 KB, 112 views)
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Old 17th September 2012, 06:02 AM   #12
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Originally Posted by weltersys View Post
Most of your questions have been answered, but use the 30 Hz filter, the 50 Hz will cut too much.
Polyfill definitely will reduce output in the sub range (30-120 Hz), and LTD02 is correct, in your undersized box, the difference between your actual tuning of 33.5 and 38 does not amount to much.
Attached LTD02's sims and Peavey's actual cabinet response curves for comparison.
If you want to get low bass in a 5 cube cab, a pair of speakers like the Lab 12 or TC Epic 12 will kill the Low rider. But you already have built a too small cabinet for your 18", so solly.
Turbodawg's bracing suggestions are valid, surprisingly bracing affects the upper "kick" sub range (around 80-160 Hz) more than the bottom octaves.
If you jam a divider (or two) in the port (use some paintable black caulk for sealant) it will help bracing and also make the port a bit more effective.
As somebody else mentioned, multiple ports also allow for "step down" (Electro-Voice term) operation by plugging a port the tuning goes down.
Yeah I decided the box frequency is fine at 34hz. I'm still going to reinforce the bracing yes.

and whelp damn at this sub/box combo... I definitely don't want to be stuck with an average system. Like I said it hits decent with some songs, then others a bit flat at times. Yet overall not as I expected. Nothing chest pounding. If it doesn't work out I'll look to replace with a different 18" or retrofit smaller size sub(s)...

One thing.. I am using a 25ft unbalanced signal from my crappy home theater receiver. I've been told to level match the signal so I was going to pick up a DI box to boost and match. Which should help tremendously. Should I still do so? Or is this sub/box the real culprit..

It kind of sounds like an elephant farting through a kazoo...
Quote:
Hey Mister DJ, could you turn off the suck!? No? Here's your problem — you can't rust run consumer-grade unbalanced RCA-level high-impedance lines into a professional sound system... DUH! Take this handy ART CLEANBoxPro and plug into the system the right way, with impedance-matched balanced XLR cables. Yeah, the CLEANBoxPro can handle your iPod's ⅛" plug too, no problem. Ahh... that's much better, hear how the high end comes through nice and clear and the bass no longer sounds like an elephant farting into a kazoo? And it's all thanks to this ART CLEANBoxPro. Now, could I please have mine back? No? Oh, don't worry about it, they're cheap enough I can always afford another.

Last edited by bobbobobbo; 17th September 2012 at 06:06 AM.
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Old 17th September 2012, 06:44 AM   #13
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Quote:
Originally Posted by bobbobobbo View Post
Like I said it hits decent with some songs, then others a bit flat at times. Yet overall not as I expected. Nothing chest pounding. If it doesn't work out I'll look to replace with a different 18" or retrofit smaller size sub(s)...

One thing.. I am using a 25ft unbalanced signal from my crappy home theater receiver. I've been told to level match the signal so I was going to pick up a DI box to boost and match. Which should help tremendously. Should I still do so? Or is this sub/box the real culprit..
Usually the biggest culprit is the room, which can make mincemeat of the best sub.

Your amp can probably be driven FTB (see if you can hit the clip lights) by your crappy home theater receiver, but receivers usually have a very high "sub" output ranging upwards of 250 Hz at only 12 dB per octave, so amplifying that just makes for loads of mud on a sub like yours that has plenty of (crappy sounding) upper response, usually including a port resonance around that range.

If you are serious about having a "better than average" sub sound using a power amp, you need to get into DSP, whether using the Mini DSP, a DBX DriverackPA, the Berhringer, or whatever.
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Old 17th September 2012, 07:00 AM   #14
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Originally Posted by weltersys View Post
Usually the biggest culprit is the room, which can make mincemeat of the best sub.

Your amp can probably be driven FTB (see if you can hit the clip lights) by your crappy home theater receiver, but receivers usually have a very high "sub" output ranging upwards of 250 Hz at only 12 dB per octave, so amplifying that just makes for loads of mud on a sub like yours that has plenty of (crappy sounding) upper response, usually including a port resonance around that range.

If you are serious about having a "better than average" sub sound using a power amp, you need to get into DSP, whether using the Mini DSP, a DBX DriverackPA, the Berhringer, or whatever.
Unaware of what FTB means.. yes I can hit the clip lights. Anyway I'm getting such conflicting responses..

Quote:
The Yamaha receiver won't help. My Yamaha couldn't drive my ep4000, just not enough voltage out of the LFE. You need something to boost the signal like an art cleanbox or what was suggested before. The light will flash on the amp anyway even if it's not loud. You send a clipped signal to the amp it will clip. Mine did the same thing. After you boost the signal it'll be much better.
I don't want to get into DSP, etc. I meant better than average as in better than my basic BIC VK12 that was plugged into the same crappy home receiver in the same room. That little 250rms 12" shook the house. I thought this was going to dominate that. It just sounds a bit flattish and lacking and I'm left confused. If it's the signal going in, I'll get a proper DI box. If it's the subwoofer/box itself I'll swap out the sub.
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Old 17th September 2012, 03:05 PM   #15
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I thought this was good advice on getting your gains set properly:

First build: Dayton 15" HO and iNuke3000DSP

What are you running for the low pass crossover on this.....?
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Old 17th September 2012, 04:43 PM   #16
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Originally Posted by bobbobobbo View Post
Unaware of what FTB means.. yes I can hit the clip lights. Anyway I'm getting such conflicting responses..
FTB means "full tilt boogie", ie hitting the clip lights hard.
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Old 17th September 2012, 11:38 PM   #17
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Originally Posted by turbodawg View Post
I thought this was good advice on getting your gains set properly:

First build: Dayton 15" HO and iNuke3000DSP

What are you running for the low pass crossover on this.....?
Will look into that thread.

I'm not running a separate low pass crossover.. Just whatever the "subwoofer" out on the ht receiver provides, and/or anything on the EP2000 amp.


Also I was going to pick up this
Amazon.com: Rolls MB15 Promatch Converter: Musical Instruments

as I've read countless articles on how consumer to pro audio is just never a good thing. Can't hurt.
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Old 18th September 2012, 12:43 AM   #18
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Quote:
Originally Posted by bobbobobbo View Post
I'm not running a separate low pass crossover.. Just whatever the "subwoofer" out on the ht receiver provides, and/or anything on the EP2000 amp.
I would be concerned about this. You may be sending signal (far) above 100hz to your sub, which could be causing weird phase/time cancellations between it and your mains in the midbass. Bass "hit" is partly transient response - think of a square wave. A square wave is composed of many sine waves of various frequencies overlapping. Due to crossovers, when you send your system a kick drum, the mains and sub will both see some of it. If there is a timing difference between them, the response will not be natural. Even worse if the are both trying to send signal at 150 hz and don't match up due to location differences, resulting in cancellation. Optimally, at your crossover frequency the drivers have to be time aligned - the easiest way to do this is to have them located the same distance from the listener.
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Old 18th September 2012, 04:08 PM   #19
OscarS is offline OscarS  United States
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If you're HPF is set at 30Hz and you're tuned to ~33 Hz, the output at 33Hz is already being rolled off by the filter so the port s not doing anywhere near as much as it should. That is costing you a lot of output potential since you're not letting the port work for you. The driver is basically trying to work in a sealed box if it does not get to excite the port's fundamental resonance. Did you test T/S parameters and model this design prior to building it?
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Old 18th September 2012, 06:48 PM   #20
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Quote:
Originally Posted by turbodawg View Post
I would be concerned about this. You may be sending signal (far) above 100hz to your sub, which could be causing weird phase/time cancellations between it and your mains in the midbass. Bass "hit" is partly transient response - think of a square wave. A square wave is composed of many sine waves of various frequencies overlapping. Due to crossovers, when you send your system a kick drum, the mains and sub will both see some of it. If there is a timing difference between them, the response will not be natural. Even worse if the are both trying to send signal at 150 hz and don't match up due to location differences, resulting in cancellation. Optimally, at your crossover frequency the drivers have to be time aligned - the easiest way to do this is to have them located the same distance from the listener.
Gotcha. Will look into that and correct the signal. I've run it without the mains completely, I still get the same general response.

Quote:
Originally Posted by OscarS View Post
If you're HPF is set at 30Hz and you're tuned to ~33 Hz, the output at 33Hz is already being rolled off by the filter so the port s not doing anywhere near as much as it should. That is costing you a lot of output potential since you're not letting the port work for you. The driver is basically trying to work in a sealed box if it does not get to excite the port's fundamental resonance. Did you test T/S parameters and model this design prior to building it?
It's already being rolled off at 33? Maybe I should test with the low cut (hp) filter off... I'll be home in an hour. Some have mentioned it can be run without..

The signal is coming from the home receiver sub out, not sure if that is already sending certain filtered frequencies..

I modeled this before I built it, someone else helped me. The box came in at the smaller side for this sub, yet it would still be ok. He recommended 30hz or 35hz, with the hpf set at 30hz, I went for the middle.

Last edited by bobbobobbo; 18th September 2012 at 07:15 PM.
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