duanebrow
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Posts posted by duanebrow
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You aren't going to see much difference between 3.2 and 3.5cf. I'd use the box design you have unless you wanted something different.
Duane
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Don't cut out you normal routine completely. Bc you will get burned out. Just limit your fast-food and softdrink input.
Look at bodybuilding. Com. They have a lot of helpful advice and small programs for people getting started.
Good advise. I will add another site that will help, (way better than any diet btw) www.sparkpeople.com
You are on the right road. Don't think of it as a diet. It is a lifestyle change.
Ask someone that works at the gym if they can get you started on a work out plan. Most will do this for free.
Remember that you didn't get to 250# overnight, it took years. It will take time to get back to your goal. Don't give up! And don't worry if you stop losing weight. It's because you're building muscle.
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I'd go with a 10 over 2 8's. It's cheaper. More options that way also. A DCON and a four channel amp. Then he's ready for the front stage!
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Viper, try using sentences. You know punctuation and stuff. Makes it easier to read.
How much do you want to spend? What are your goals with this system? How much space do you want to use for the subs?
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I have heard several people say that Class D amps are not good full range. I agree that a Mono sub amp is not made to work at over ~250 hz. However I have seen several high end companies making them for home theater. (And not as an entry level product) Crown now uses this in their XLS series pro audio amps, again a full range product. So I found a Class D car amp, and I'm interested if anyone has used it. The Incriminator Audio 6.4 4-channel amplifier, sold on this site! How does this compare to a class a/b amp? Are there trade offs for going to the type of amp? I'd think that the efficiency would make it much easier on your electrical system.
If anyone has used this, what did you think?
Thanks,
Duane
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do you have it wired right and are you sure you got dual 1 ohm? you could have gotten dual 2 ohm and wired it for 4 ohm.
It never even occured to me that they may have shipped me the wrong type. Is there any easy way of checking the impedance of the coils?
Use a dmm. Set it to impedance, with the system off put the leads in the ends off the speaker wires. This should be less than or equal to 2 ohms
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Have you checked out your setup with a DMM? You can check your work that way. Both that your wired to 2 ohms and your amps output.
Also, higher power handling and being able to work in small boxes normally costs efficency. As others have said - more power! I added this because cheap subs will be louder than the higher powered ones; until they cannot handle the power and poop!
Duane
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I'd guess the amp doesn't like the one ohm load!
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I have been working on a box like that, only with 2 sa-8 subs. And the box ended up looking like yours, just a bit bigger. LOL
Duane
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All speakers sound better amped, IMHO. I'd look for a cheap used amp on criegs (sp?) list. Just make sure that the person selling it can demo it so you know it works.
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I'd look at better 10's you don't have the room to port the 8s.
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I put a 10" mtx (i don't remember the model) ported under the seat of a ext. cab 2500 about 4-5 years ago. He is still using it today. I'd think that two 10's downfiring sealed would be better than the 8s ported.
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I can model the box for you if you want. You should be able to fit 2 sa-8's under the seats.
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I like that the subs are protected. I've wanted to make a tapped horn for a while now. But I haven't figured out hornresp.
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Winisd uses system power. Or total power going to the box. I entered 800 figuring 400 to each. Because the box will be in the back port noise shouldn't be a big deal. Small boxes need longer ports than larger boxes to be tuned the same. It's a compromise. Use the biggest port you can make work. Point the Port away from the people in the car. Flare or roundover the port ends to help.
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True.. port will be 12.5 x 2 x 28 Thanks for the catch!
So that makes my port velocity 21.5 m/sec. Is that still OK?
Recalculating volume shows total space is now 1.67 ft cubed total or .93 per sub.
Also, one question. By just shortening the port, I see that it increases the velocity of air. If I don't shorten the port, would that make the tune higher or lower? Using WinISD, I don't see how to let the tune change
Hi Dave,
The longer the port the lower the tuning. The bigger the port the longer it will need to be to tuned the same. Select the "box" tab and you can change tuning to what ever you want. (you can use the arrow keys to change values once you click on it.)
You can also open up a second project using the same drivers. then play with that to see what is changing. (you will want to change the color of the plot line in the "plot" tab)
Port velocity should be kept under 17 m/s if possible. This often results in very long ports that are not practical. 21 is still very good. I'd try rounding over the edges of the port to help eliminate port noise.
Dave - how much power did you model these at? I entered 800 for system power. I am seeing 30 m/s at 34hz.
Duane
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One amp is easier. You don't have to wire a second amp or match the gains. It takes up less space and costs less.
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Something looks wrong with the treo. Have you done a sweep to see if it really has that big of a boost?
And don't forget that the port must be subtracted from the total box volume. Also, when you space up the sub, remember that the pole vent needs room to breath.
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Looks sweet! How does putting the subs in the ports change things, is it a tapped horn?
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Thank you for the replies,
I have a TB 740c. It's a 8" 150watt sub rated at 120-150rms. 12mm X-max. Anyway I modeled it ported and 6th order BP. ported goes a bit lower (33hz f3), but the 6th order is about 2-3 db louder. Because this isn't going to get very loud off a single 8, I'm leaning toward the BP. Btw f3's on the BP are 38-84hz. I will need 3" ports and I don't know if I can make it fit.
Any one here designing 6th order boxes? Should I start a new thread about the box? I'd like a second opinion if anyone can.
Here is the sizes: .275cf @ 66hz and .5cf @ 37hz
And a Pic:
Thank you,
Duane
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Ok, first what is the size of the box you have? What kind of port and what size. Also could you give the size of the space you have to work with for this new build?
Duane
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Hi, I was wondering if anyone has made or heard a sub placed between the front seats. I have a venture mini van. I can have about 1cf of space to work with (id). If you have done this or heard a setup like this please let me know what you thought.
Thanks,
Duane
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I listened to several of these songs that rlp sent me. Very nice, great showoff songs.
Ridin, send me what ever songs you would like to know what fr they hit at. I use spectrumlab to see this if you want to give it a try. Fwiw oxy cotton hits at 25 Hz. But some are much higher.
Duane
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This is the latest version of winisd.
http://www.linearteam.org/download/winisd-07x.exe
It works well with Windows 7. If you want to do this for yourself, please let me know and I'll help you out. It has some issues with the way you enter the specs for your driver. This is a pain until you figure it out.
I can design a box if you want, just send me a message.
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PORT NOISE HELP
in Technical Info & How To's
Posted · Edited by Duane
Time to build a new box! You need to model what you have. Then design to correct the problem. If you can post the t/s specs, or a link to them. I can look into it. And how much power you are using.
Duane