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Old 12th June 2006, 06:54 AM   #1
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Question Subwoofers and box questions.

I'm going to have a few general questions.

Does a sub that handles more watts have deeper bass than an equal size sub that handles less watts?

If I am building a system for the deepest possible sounding bass, would I want a sealed box or a bandpass box?

I know more subs make for louder bass, but does it also make the bass sound deeper?
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Old 12th June 2006, 07:09 AM   #2
Jennice is offline Jennice  Denmark
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No, More doesn't mean deeper.

How deep the bass driver (woofer) can play, depends on its own physical design, and the box it is placed in.
For the box, there is the size which is important, and should be made for the driver you decide to use, and the type.
The modt conventional are sealed enclosures, and bass-reflex ( also called ported, or vented).

To get an idea, download the free tool WinISD from http://www.linearteam.dk/

To use the program, you will need to find the T/S parameters for the drivers you consider (usually available on the manufacturers home page).
In WinISD, create a driver with the data (from the manufacturer), and create a project. Choose Vented or sealed enclosure, and it will give you an idea of how deep it will go.
The nice thing with WinISD is that you can have more projects (driver in enclosure) open at once, and see compare the results to find the type you prefer.

When you've found something you like, check the box size, as you may be surprised to see how big it is suggested to be (internal volume). For vented, also the port size is suggested.
You can manually enter/change the parameters and watch the change in response. Sometimes you can get away with a somewhat smaller box than the programs own ideal curve suggests, if you're willing to accept small compromises.

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Old 12th June 2006, 01:33 PM   #3
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More means louder, not deeper
Higher power handling by itself means nothing, not even that it will get louder, and it definitely doesn't mean it can go lower

As for what setup will give you the deepest bass, well that depends on two things, your car and your definition of deep bass. WinISD isn't a very effective tool for that kind of thing, because once you put the sub/enclosure in a car it will look nothing like the graph you see. Cabin gain will give you a boost of ~12dB/oct that starts at your car's resonant frequency, normally somewhere between 50-70hz. A typical sealed box will have a 12dB/oct rolloff starting around 50-60hz, and if you see that in WinISD it will look like crap, but once you put it in a car, that rolloff mixed with cabin gain can often give you a response that goes lower and stays flatter than any other possible setup.

As for your definition of deep...even though a sealed setup can normally go far lower before dropping off than a ported setup, a ported setup will normally have a very large boost around the tuning frequency. If you use a tuning frequency around 28-30hz (the lowest most music goes), that will make the setup much louder at the lowest frequencies present in most music, which sounds "deeper" to many people who don't know any different. I personally think that huge boost sounds like crap, but other people like it, it's all personal preference.

The best idea IMO is to start sealed. You can use WinISD to see what kind of Q the recommended sealed box size has. If it's well below .7 then you might consider making the box a bit larger than spec. After you get the box built you can try it out and see how it sounds, adding blocks to the inside to take up volume, or adding polyfill to the inside to "add" volume. If you still aren't satisfied, then you can try building a low tuned ported enclosure and see if that fits your taste better.
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Old 23rd June 2006, 05:07 AM   #4
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How would u a graph response? of ure car??
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Old 23rd June 2006, 06:23 AM   #5
dangus is offline dangus  Canada
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Measure the response of the sub in its box outside, in the middle of a parking lot. I'm not sure if it would be better to do nearfield or 1 meter. Do both.

Put the sub in the car. Stick the mic someplace standard, maybe up against the windshield like DB Dragracing does, or in the driver's seat. Measure the response.

The difference between the two measured responses should be the "transfer function" of the car.

Someone correct me if I'm wrong, or fill in the details I missed, please.
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Old 23rd June 2006, 12:34 PM   #6
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I dont understand, you put the mic in the car and wat do u measure it with, like a program on the computer(wat program) or device??
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Old 23rd June 2006, 02:14 PM   #7
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Quote:
Originally posted by dangus
Measure the response of the sub in its box outside, in the middle of a parking lot. I'm not sure if it would be better to do nearfield or 1 meter. Do both.

Put the sub in the car. Stick the mic someplace standard, maybe up against the windshield like DB Dragracing does, or in the driver's seat. Measure the response.

The difference between the two measured responses should be the "transfer function" of the car.

Someone correct me if I'm wrong, or fill in the details I missed, please.
That's right


Quote:
Originally posted by rollin24's
I dont understand, you put the mic in the car and wat do u measure it with, like a program on the computer(wat program) or device??
It's up to you, you could use anything from a radioshack spl meter and a piece of notebook paper to an RTA
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Old 28th June 2006, 03:40 AM   #8
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Quote:
Originally posted by sr20dem0n



It's up to you, you could use anything from a radioshack spl meter and a piece of notebook paper to an RTA
but you have to be playing a test CD, which has seperate tracks for each frequency. You play whichever tracks you want to test, and then compare... SPL meters are about $50
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Old 28th June 2006, 03:31 PM   #9
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is there a program on the computer were specific frequency's play threw the speaker and the mic records the frequency response of the area u are playing it in
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