winisd question

[Mr Bojangles 10+ year member]

I know that anything below the -3db the driver will not produce very well, but what about a "peak" or anything above the 0db line? Is it not good to have a peak?

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[Mr Bojangles 10+ year member]

bump

 

[Mr Bojangles 10+ year member]

I know you fellas have to know this.. c'mon guys

 

[Immacomputer 10+ year member]

Anything above the 0dB line is gain and it will probably give a peak when put in a vehicle. How much of a peak will depend on the transfer function of the vehicle. Depending on the transfer function, the gain from the sub/enclosure may not be as peaky as it was theoretically. That's why those graphs are to be taken with a grain of salt without having a good understanding of your transfer function.

 

[Mr Bojangles 10+ year member]

K so should i just pick the smoothest possible curve and not have a gain or peak?

 

[Immacomputer 10+ year member]

Not necessarily.

 

[Mr Bojangles 10+ year member]

Also when figuring up the actual size of the box do i need to add the port displacement volume to the total volume of the box and make the actual box that much bigger?

 

[Mr Bojangles 10+ year member]

Not necessarily.

Is it better to have a +3db gain? or does that depend on the truck it's going in?

 

[Immacomputer 10+ year member]

Also when figuring up the actual size of the box do i need to add the port displacement volume to the total volume of the box and make the actual box that much bigger?

Yes, the volume you enter into winisd is the net volume (wood, port, and sub displacements are not taken into consideration).

How much gain you want is completely dependent on your vehicle's transfer function and what you're looking to get out of the system.

 

[audioholic 5,000+ posts]

I think I see where these questions are leading.

In theory, the best thing to do would be to go out and get an RTA, 'map' out your vehicle's transfer function via frequency response, and then model your sub enclosure's response to counter this exactly, leaving you with an in-car response that is naturally smooth.

Now to the real world. You cannot build an enclosure that counter's your vehicle's transfer function map perfectly. If you are serious about it, build an enclosure that gets you in the ballpark, then let your processor do the rest. Most people just build for the most predictable response form the enclosure (generally flat) and then adjust for their vehicle's transfer function via their sound processor exclusively.

Hope this helps.