Well, I've looked through some of the threads on this site and I take it bottoming out hurts the voice coil and can ruin a sub, right?
Anyways, I have 4 MA Audio subwoofers (MA120XE, 12", 350 watts RMS) installed in a single box about 6.5-7 cu feet (before displacement). The subs hit hard, and I'm only pushing 1000 watts RMS to them just to be on the safe side. Turning up the gain some though obviously makes them hit harder, but I don't know if I'm bottoming them out or not. How can I tell?
Anyways, I have 4 MA Audio subwoofers (MA120XE, 12", 350 watts RMS) installed in a single box about 6.5-7 cu feet (before displacement). The subs hit hard, and I'm only pushing 1000 watts RMS to them just to be on the safe side. Turning up the gain some though obviously makes them hit harder, but I don't know if I'm bottoming them out or not. How can I tell?
69CamaroSS396 said:
It's hard to know if they're clacking, my van rattles too much to differentiate the two things.
Well, I have the gain at about +5dB, not anything like +12. They don't sound distorted, at least not through my vans rattling, but would the clacking sound of it bottoming out be like a triangle (the musical instrument), or like a 50 lb piece of steel falling onto more steel.
you could be hearing the sound of a square wave, if the amp is being over driven by having the gain too high on the head unit or the amp. some amps can be over driven even with the gain set to a mid to low level, it depends on the head unit RCA preamp output voltage, if thats what your using, make sure that the voltage input rating for the amp is set to handle what ever voltage the head unit can send.
bottoming out a speaker is most of the time a loud clonk, you should not look to hear for the clonk as a guide to too much power, since it can easily kill the sub,. check the output voltage on the amp, and calculate power output and set it below the recomended by the manufacturer, you can also check the shape of the output wave using an oscilloscope to make sure its not square, you can measure the voltage with the scope so you can again calculate power output of the amp, once this is done make sure that there is no bottoming out of the sub.
what amp are you running on those subs?
and what head unit?
laters
bottoming out a speaker is most of the time a loud clonk, you should not look to hear for the clonk as a guide to too much power, since it can easily kill the sub,. check the output voltage on the amp, and calculate power output and set it below the recomended by the manufacturer, you can also check the shape of the output wave using an oscilloscope to make sure its not square, you can measure the voltage with the scope so you can again calculate power output of the amp, once this is done make sure that there is no bottoming out of the sub.
what amp are you running on those subs?
and what head unit?
laters
Very. Tap a PVC coupler or a heavy plastic drinking glass on a counter top, sounds something like that. Not likely to be confused with rattles.
Trouble is, they can bottom out lightly without being very audible. Though not as serious as really slamming the backplate, it can still distort the VC former and have cumulative effects.
ninjatanzen said:
I think the gain needs to be set correctly before going any further. It can't be total guesswork. Sounds like you may not be sure whether it's correct or not. Maybe you are, but if that is taken out of the equation, the troubleshooting becomes less complicated.
As mentioned, you need to know whether the head unit and amp/amps are even compatible.
This reminds me of a situation I encountered in my neighborhood. A local kid had an Eclipse HU w/8V pre-outs, an audiobahn 4 channel amp driving his front stage, and an older yard sale Alphasonik 2 channel bridged driving his subs. The audiobahn could handle the 8V, but the older amp only accepted up to 1V input. Bad deal because the old amp was driven to its rated power with well less than 1/2 volume from the HU. From that point to the user's actual listening level, the old amp was being driven from mild into severe clipping.
boricuaso said:
Ok, you and someone else asked the same question. The head unit is a Pioneer DEH-1500 with and output of 2.2V
The amp is a Alpine MRP-M1000 and has a separate knob for the gain and the Voltage; the Voltage can be set from 0.2-4V, but it's almost guess work as there are no indications as to what you're set at.
I think my dead uncle has an oscilloscope sooo I'll have my brother pick that up and check it out for me.
Sorry it's taking me forever to reply, I'm under the lil noobie moderation thing.
ninjatanzen said:
Explain what it says on the two controls you mentioned above. I have never used Alpine amps, but it sounds as though you are describing the bass EQ, (0dB-12dB@50hz), and the gain or input sensitivity adjustment, which is marked in V, and these are two completely different things.
what about....
They don't sound distorted, at least not through my vans rattling,
I'm surprised nobody mentioned the rattles in the van!
Indoors, if you got ornaments rattling and buzzing, you either remove the offending items or, you blu-tak them or something. Maybe something could be permanently attached with liquid nails or tighten bolts, apply bitumen pads to panels, (roofers felt), even?
Take the sub out of the van and set it up
Mike
They don't sound distorted, at least not through my vans rattling,
I'm surprised nobody mentioned the rattles in the van!
Indoors, if you got ornaments rattling and buzzing, you either remove the offending items or, you blu-tak them or something. Maybe something could be permanently attached with liquid nails or tighten bolts, apply bitumen pads to panels, (roofers felt), even?
Take the sub out of the van and set it up
Mike
Re: what about....
Yeah, well I don't want to permanently close the hatch of my van heh. What's the roofers felt?
Yeah, I was actually thinking about that. I'll take it out tomorrow and set it up.
Another quick question, does internal bracing really help? I put none in a 4x12 box and it's not falling apart or anything. It just flex's on loud low notes.
mikee55 said:They don't sound distorted, at least not through my vans rattling,
I'm surprised nobody mentioned the rattles in the van!
Indoors, if you got ornaments rattling and buzzing, you either remove the offending items or, you blu-tak them or something. Maybe something could be permanently attached with liquid nails or tighten bolts, apply bitumen pads to panels, (roofers felt), even?
Take the sub out of the van and set it up
Mike
Yeah, well I don't want to permanently close the hatch of my van heh. What's the roofers felt?
Yeah, I was actually thinking about that. I'll take it out tomorrow and set it up.
Another quick question, does internal bracing really help? I put none in a 4x12 box and it's not falling apart or anything. It just flex's on loud low notes.
hello again
Roofers felt .
When you build a building, say with a flat roof, you need a waterproof covering.
http://www.clevedonfeltroofing.co.uk/
Would it be too much, to ask for an image? Can you upload some pics?
And you lot, too! I wanna see more pics, wheres the gallery?
I would, but my Digicam is poorly
Just a quick look at your box, we could tell you more
Mike
Roofers felt .
When you build a building, say with a flat roof, you need a waterproof covering.
http://www.clevedonfeltroofing.co.uk/
Would it be too much, to ask for an image? Can you upload some pics?
And you lot, too! I wanna see more pics, wheres the gallery?
I would, but my Digicam is poorly
Just a quick look at your box, we could tell you more
Mike
It's the car with all it's rattles and non-linear flexings what trashes the sound.
Car acoustics have *far* more impact on sound quality than amplifiers or speakers, or even a too weak subwoofer enclosure. Bad car acoustics distort the sound to the point where you can't tell if amplifiers and speakers are being overdriven or not (sad!)
The stiffness of the door panels, when they act as enclosures for front midbass speakers, also has a tremendous impact on sound quality. The worst midbass speaker in the world placed on a strong and quiet door panel has more "punch" than the best one on a weak panel.
Car acoustics have *far* more impact on sound quality than amplifiers or speakers, or even a too weak subwoofer enclosure. Bad car acoustics distort the sound to the point where you can't tell if amplifiers and speakers are being overdriven or not (sad!)
The stiffness of the door panels, when they act as enclosures for front midbass speakers, also has a tremendous impact on sound quality. The worst midbass speaker in the world placed on a strong and quiet door panel has more "punch" than the best one on a weak panel.
Okay...
Hi ninjatanzen,
I have to admit I had no idea your box would be like that! I'm also no expert or good at much, others will always Know more. People on this site have always tried to help me, so I try to return the help.
Is that just a box?
Did you just measure your van to see what fits best, ( always a factor, but)?
Also, did you find the correct volume for your drivers?
Are your joints sound, and the baffle needs to be braced to the rear panel?
Would a deeper box be possible?
Can I suggest that if the box could be different, would the rear wave be dealt better, by having further to travel, before its reflected off of the back panel?
Do you have stuffing?
Before you brace with a length of 4 by 4 front to back, center of the baffle, could a matrix of partitions help, which have, say 2" holes drilled into them?
Whats inside the box???
Mike
Hi ninjatanzen,
I have to admit I had no idea your box would be like that! I'm also no expert or good at much, others will always Know more. People on this site have always tried to help me, so I try to return the help.
Is that just a box?
Did you just measure your van to see what fits best, ( always a factor, but)?
Also, did you find the correct volume for your drivers?
Are your joints sound, and the baffle needs to be braced to the rear panel?
Would a deeper box be possible?
Can I suggest that if the box could be different, would the rear wave be dealt better, by having further to travel, before its reflected off of the back panel?
Do you have stuffing?
Before you brace with a length of 4 by 4 front to back, center of the baffle, could a matrix of partitions help, which have, say 2" holes drilled into them?
Whats inside the box???
Mike
Re: Okay...
It's just a box, yes. I did measure my van, and that fits where the rear seats used to go. I could've made it taller and not a wide I suppose.
I didn't get the perfect volume for my drivers, but I got an optimal one to my knowledge and advanced calculations (lol jk, but I went over everything I knew when figuring out the volume).
I was going to brace my baffle, but somehow I just forgot to. So, with that being loose and flexing, my joints are no longer tight.
I have stuffing, but wasn't sure how well that would really work in such a big box, as I did not have enough.
So overall it's basically a box :x
I'm definitely thinking of making/buying a better one.
mikee55 said:Hi ninjatanzen,
I have to admit I had no idea your box would be like that! I'm also no expert or good at much, others will always Know more. People on this site have always tried to help me, so I try to return the help.
Is that just a box?
Did you just measure your van to see what fits best, ( always a factor, but)?
Also, did you find the correct volume for your drivers?
Are your joints sound, and the baffle needs to be braced to the rear panel?
Would a deeper box be possible?
Can I suggest that if the box could be different, would the rear wave be dealt better, by having further to travel, before its reflected off of the back panel?
Do you have stuffing?
Before you brace with a length of 4 by 4 front to back, center of the baffle, could a matrix of partitions help, which have, say 2" holes drilled into them?
Whats inside the box???
Mike
It's just a box, yes. I did measure my van, and that fits where the rear seats used to go. I could've made it taller and not a wide I suppose.
I didn't get the perfect volume for my drivers, but I got an optimal one to my knowledge and advanced calculations (lol jk, but I went over everything I knew when figuring out the volume).
I was going to brace my baffle, but somehow I just forgot to. So, with that being loose and flexing, my joints are no longer tight.
I have stuffing, but wasn't sure how well that would really work in such a big box, as I did not have enough.
So overall it's basically a box :x
I'm definitely thinking of making/buying a better one.
Dude
don't buy one. This site could help you. You could learn quite easily to measure your drivers Thiele/Small parameters, usually a PC with a sound card and a Digital Multimeter capable of ac milliamps. See here
http://www.readresearch.co.uk/html/utilities.htm or here
http://sound.westhost.com/tsp.htm
Throw that box back in ya van, so you got some toones, whilst you design your box.
Re measure your van and look again at what room you can afford to use.
Post or search for a better ratio of height width depth of your box, and try to design for it.
Search for cabinet construction techniques, this sub would be an effort to be proud of, I've built loads of boxes that I thought sounded right, I followed info and had help from the man himself, richie00boy, and with a driver I had gotten used to, but had no spec. I measured the T/S parameters and made a box. I was surprised at how good it sounded once correctly done. The feel good factor outweighs any purchased pre made box, especially if its not built to the right driver.
A double skin of 18mm mdf and 18mm ply would make a stiff box a Router would flush mount your drivers and finish off edges by rounding them over.
A 1000w r.m.s of juice would be better served up to you, no?
Mike
don't buy one. This site could help you. You could learn quite easily to measure your drivers Thiele/Small parameters, usually a PC with a sound card and a Digital Multimeter capable of ac milliamps. See here
http://www.readresearch.co.uk/html/utilities.htm or here
http://sound.westhost.com/tsp.htm
Throw that box back in ya van, so you got some toones, whilst you design your box.
Re measure your van and look again at what room you can afford to use.
Post or search for a better ratio of height width depth of your box, and try to design for it.
Search for cabinet construction techniques, this sub would be an effort to be proud of, I've built loads of boxes that I thought sounded right, I followed info and had help from the man himself, richie00boy, and with a driver I had gotten used to, but had no spec. I measured the T/S parameters and made a box. I was surprised at how good it sounded once correctly done. The feel good factor outweighs any purchased pre made box, especially if its not built to the right driver.
A double skin of 18mm mdf and 18mm ply would make a stiff box a Router would flush mount your drivers and finish off edges by rounding them over.
A 1000w r.m.s of juice would be better served up to you, no?
Mike
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