i want to learn about box building simulators like winISD. can anyone verify how accurate these can be or not be?
which is an easy one to learn on for first time users?
i am trying to build a a box for a kicker L7 12" and i keep getting different specs from different people and all i can get across the board from everyone is that they need big boxes. the vehicle i am working on doesnt really have any space limitations and i want the biggest bang for my buck.
so far i have the most faith in these specs from diy member "GM" 6.2 ft^3 tuned around 27-28 Hz with an 8" diameter vent 23-24"
which is an easy one to learn on for first time users?
i am trying to build a a box for a kicker L7 12" and i keep getting different specs from different people and all i can get across the board from everyone is that they need big boxes. the vehicle i am working on doesnt really have any space limitations and i want the biggest bang for my buck.
so far i have the most faith in these specs from diy member "GM" 6.2 ft^3 tuned around 27-28 Hz with an 8" diameter vent 23-24"
The accuracy of simuators isn't the reason for variations. The user must define a target response, and the best target is a combination of opinion, physics, reasonable enclosure volume, power handling, etc.
Add to that Glowbug's point, and you'll see why I don't bother with box simulators.
Disclaimer: Not that there's anything wrong with that!
Add to that Glowbug's point, and you'll see why I don't bother with box simulators.
Disclaimer: Not that there's anything wrong with that!
so is there anything to be learned or gained from building a virtual box first? building 2x 6.2 cubic foot boxes is a pretty big commitment considering i havent been able to find anyone else use a box this big for a speaker this size.
i asked kicker for their recomendations and his dimensions were completely out to lunch.
im not to sure who to listen to
i asked kicker for their recomendations and his dimensions were completely out to lunch.
im not to sure who to listen to
I measure my drivers and use the basic equations published in Speaker Builder many years ago. The boxes have always performed very closely to the predictions, but as said above, radiating into the small volume of a vehicle may throw things off by quite a bit. The newer modeling programs may take a few more things into account, but the fundamental numbers are nothing you can't generate with an Excel spreadsheet or simple basic program. I wouldn't consider building a box for drivers I hadn't measured unless the company had a long history of publishing confirmed accurate specs on their drivers.
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Conrad's point is about measuring drivers is well taken. Specs can vary quite a bit from advertised, even 20% variation probably wouldn't be unusual.
Software can be helpful if you aren't accustomed to visualizing a response graph or comfortable with a bit of math or thinking in terms of numbers. But in the end, it's only a fancy calculator. You have to filter the information and decide what's the best compromise for yourself.
I've read many of GM's posts, and he knows what he's doing. The question is: does he know what you're looking for out of these woofers?
Software can be helpful if you aren't accustomed to visualizing a response graph or comfortable with a bit of math or thinking in terms of numbers. But in the end, it's only a fancy calculator. You have to filter the information and decide what's the best compromise for yourself.
I've read many of GM's posts, and he knows what he's doing. The question is: does he know what you're looking for out of these woofers?
The question is: does he know what you're looking for out of these woofers?
actually i am so new to this that i dont know which questions to ask yet. its why i was hoping that i could experiment with these box sims first. i have built 2 other boxes that failed miserably and it is time consuming and expensive just building boxes to see if they work.
my point is that to me it would make sense that if you tune a box to handle the power i plan on using and also if i use it to make sure i have the box acting as a brake at a certain frequency range. then i build the box and put it in a car then atleast i should be close
with the specs that kicker gave me, i built that box and GM ran the dimensions and told me that the box is designed to handle aprox 25 watts and believe me the box sounds that way exactly, any volume at all and the speaker starts clipping and the VC former is just smashing into the other parts of the speaker. i dont know what the guy at kicker was smoking but i lost all faith in there tech department, because i built the box exactly as he described
i understand that cabin gain cant be taken into consideration and probably other factors are too much of a variable to model. but there must be some information that can be taken from modeling first then building.
actually i am so new to this that i dont know which questions to ask yet. its why i was hoping that i could experiment with these box sims first. i have built 2 other boxes that failed miserably and it is time consuming and expensive just building boxes to see if they work.
my point is that to me it would make sense that if you tune a box to handle the power i plan on using and also if i use it to make sure i have the box acting as a brake at a certain frequency range. then i build the box and put it in a car then atleast i should be close
with the specs that kicker gave me, i built that box and GM ran the dimensions and told me that the box is designed to handle aprox 25 watts and believe me the box sounds that way exactly, any volume at all and the speaker starts clipping and the VC former is just smashing into the other parts of the speaker. i dont know what the guy at kicker was smoking but i lost all faith in there tech department, because i built the box exactly as he described
i understand that cabin gain cant be taken into consideration and probably other factors are too much of a variable to model. but there must be some information that can be taken from modeling first then building.
It might be worth a look around on car audio sites, to see if anyone has measured the cabin gain of lots of different cars, then pick the car closest to yours and you'll know (roughly) how the sub will react in the environment you'd put it in.
A lot of car audio people swear by the Kicker, but it takes up too much space in a (properly) designed box. It might be better to look around for speakers that go similar bass in a smaller box, then you'd be able to fit more speakers!
What exactly do you want from this sub? High SPL or deep bass? How much power do you plan to put in?
Chris
A lot of car audio people swear by the Kicker, but it takes up too much space in a (properly) designed box. It might be better to look around for speakers that go similar bass in a smaller box, then you'd be able to fit more speakers!
What exactly do you want from this sub? High SPL or deep bass? How much power do you plan to put in?
Chris
That's how we all learned! It encourages you to do exactly what you are doing now. Dig.Though they didn't do what you wanted, did they do anything well?
Don't expect the box or port to be a "brake". Speaker cone motion will be at a minimum around port frequency...
But if that is chosen too low for the woofer/box combination -the woofer's output will already be falling off so the port's useful output will be reduced, and the assitance in power handling will not be effective in the woofer's critical lower range before the port begins to help.
If chosen too high for the woofer/box combination -there will be a bump in response accompanied by poor transient behavior, and the woofer will be completely unloaded below the port frequency. If you tune the port to 40Hz, the woofer will have NO power handling at 20Hz.
It's a balancing act, and what sounds great to some sounds like garbage to others.
Absolutely. If you could measure or estimate what the previous box did and compare that to a simulation, the difference would be the effect of the truck's interior. That effect can be assumed to be in place with any other similar design (woofer placement, port location, large changes to box size in relation to the cabin, etc can make changes).
If you like the sound of GM's large box with the L7's but don't want to give up that much space, you can use 4 of them in isobarik configuration. This will cut the box size in half, but you will have to power 4 of them while only getting output equivalent to a 2 woofer system. Very inefficient and expensive, but performance is good. It may even make more sense to choose different woofers, but it's an option that works well.
L7's have isobarik properties built into them. I don't think they are designed to be iso'd.
Comparison is where its at if you can't measure response. Just toss any sub/box in the car and EQ it the way you want. What ever your EQ says when you are done is what you want to add to the curve on your new sub. So if you boosted 30Hz then you need more of it. Model the box and your prospective new subs, look to change the curve where you EQ'd it. Yes it is rough because you don't know exactly how many dB, but it gives a good idea. I can get rid of bass easy but I can't make more so I error on the side of more sub.
ok ill try this aproach. what if my goal is to drive these subs as loud and as hard as possible till i melted the coils or tore the spider out of them. how would i go about designing a box that would get theis job done?
someone else posted that seems to make sense. if i end up with too much bass i can always just turn the gains down.
in response to the question of " did the kicker specs do anything worthwhile" the answer is no. from what i can tell (and im new at this) the box almost acted like it was doing nothing at all. i was under the assumption that a well designed speaker box will allow you to drive a speaker harder and it will be louder? is this incorrect?
can anyone agree or disagree with the specs i got from gm?
someone else posted that seems to make sense. if i end up with too much bass i can always just turn the gains down.
in response to the question of " did the kicker specs do anything worthwhile" the answer is no. from what i can tell (and im new at this) the box almost acted like it was doing nothing at all. i was under the assumption that a well designed speaker box will allow you to drive a speaker harder and it will be louder? is this incorrect?
can anyone agree or disagree with the specs i got from gm?
Actually what tends to happen is a maker will recommend a smaller box so the sub can't xmax so easy. Then it sounds nasty because the response is all humped up like an SPL box...because it is one. Sure it will go loud until you cook it. Larger box will have more bottom and sound better, but it might xmax at some point and eventually trash the sub, depending just how big and what sub. Besides everyone wants to hear they only need .5cf for a 15.
If you want loud that is SPL. Just get the specs of the sub and punch them into winISD, make a ported box that peaks at 50Hz. Put a subsonic under what the port is tuned to. That should be the most output. It is typical what the manufacturer recommends is that or maybe lightly smaller. You will want a large port.
I would not rely too much on published T/S. They can be very inaccurate.
These are the published T/S of a KICKER C15.
Fs = 21.7 Hz
Vas = 272.33L
Qes = 0.397
Qts = 0.383
Got myself one. Brand new. Measured the T/S with my LMS (Delta Mass=260grams weight)
Fs = 23.71 Hz
Vas = 156.75L
Qes = 0.86
Qts = 0.79
The discrepancies in Vas, Qes and Qts are simply amazing.
According to their T/S, optimum loading for Q=0.707 is in a 110L sealed box with F3=39Hz
From my measurements, loaded in the same 110L sealed box will result in Q=1.23 with F3 = 27Hz.
I can work my way round this C15 but it goes to show how unreliable published T/S are.
Mike
These are the published T/S of a KICKER C15.
Fs = 21.7 Hz
Vas = 272.33L
Qes = 0.397
Qts = 0.383
Got myself one. Brand new. Measured the T/S with my LMS (Delta Mass=260grams weight)
Fs = 23.71 Hz
Vas = 156.75L
Qes = 0.86
Qts = 0.79
The discrepancies in Vas, Qes and Qts are simply amazing.
According to their T/S, optimum loading for Q=0.707 is in a 110L sealed box with F3=39Hz
From my measurements, loaded in the same 110L sealed box will result in Q=1.23 with F3 = 27Hz.
I can work my way round this C15 but it goes to show how unreliable published T/S are.
Mike
Mike, that's a ridiculous difference. IMHO, that would indicate either a misprint on the specsheet, a different version of the woofer, or pathetic quality control.
Did you give it some break-in time? Shouldn't make THAT much difference...
If this is a current model, it looks like a prime candidate for IB. I wouldn't mind having a pair that measured like yours.
Sure the specs are for the version you recieved?
And yes, if this is typical, they shouldn't bother publishing T/S information.
Did you give it some break-in time? Shouldn't make THAT much difference...
If this is a current model, it looks like a prime candidate for IB. I wouldn't mind having a pair that measured like yours.
Sure the specs are for the version you recieved?
And yes, if this is typical, they shouldn't bother publishing T/S information.
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