I’ve got a chart that needs some opinions
Printed From: the12volt.com
Forum Name: Car Audio
Forum Discription: Car Stereos, Amplifiers, Crossovers, Processors, Speakers, Subwoofers, etc.
URL: https://www.the12volt.com/installbay/forum_posts.asp?tid=29288
Printed Date: May 21, 2024 at 1:50 PM
Topic: I’ve got a chart that needs some opinions
Posted By: Disaster092
Subject: I’ve got a chart that needs some opinions
Date Posted: March 29, 2004 at 9:09 PM
Hey guys. I made up this plot using Blaubox. I was curious to know what would happen if my 9 year old MTX Black Gold 10" sub was to be compared to my new $20 Roadmaster 8" Wal-Mart sub. So after some research, i found the phone number of the Roadmaster company and got my hands on the t/s parameters. Strangely enough the optimal box size for this sub is 1.25 cu ft. That just seems really big for a 100w rms 8" sub, but any way... So here are the results i got using the enclsure my MTX is in right now Vs what the 8" is going to be in. Let me know what i'm lookin at here. Just something i did for fun, lookin for a few opinions about the 2 subs. Based on this chart alone, which would you think is the better sub. My vote is the MTX, seems to have a nice smooth curve, not so sharp and peaky. 
Replies:
Posted By: auex
Date Posted: March 29, 2004 at 9:38 PM
Graphs can be deceiving, the formulas that are used to calculate them are based on home audio dynamics (more waves then pressure). They should be used as reference because subs don't perform the same in a car as they would in a home.
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Posted By: DYohn
Date Posted: March 29, 2004 at 9:47 PM
auex is absolutely right. Plus, it looks like you did not input the optimum size enclosure data for your "Roadking" in the test. One interesting thing about your graphs is if the port tuning frequency is 35 Hz, then why is your optimum performance up around 60 or 80 Hz? Where is the 35 Hz going? Why does the program predict a relatively flat response at about -3db out past 500 Hz? The Blaubox program was written with pre-determined parameters for Blaupunkt woofers in it, by the way. Even if your response curve is somewhat accurate, I predict those $20 Wal Mart POS drivers would be Road KILL after about a week - if they last that long. I believe these "speakers" (and I use the term loosly) are actually made by the same Chinese company that made the old Mobile Authority "Thump" line. These were aptly named, as "Thump" is the sound they made when you tossed them into the garbage can after they blew at 50% of their supposedly rated power input or wore out and started sounding like cardboard boxes after about three CDs.
Posted By: Disaster092
Date Posted: March 30, 2004 at 7:51 AM
HAHAHAHA! I actually have 2 of those "thumps" i have two 15" thump subs. I've never used em, but i got them for free so i wasn't complaining. Well, actually i went ahead and put in the "optimal" box cu ft and it turned out looking just like the MTX line, only about 5 db lower. The optimal is also a sealed box, so i might end up sealing it up, and just making the spot where the ports are into more little windows.
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Posted By: Disaster092
Date Posted: March 30, 2004 at 7:58 AM
I should see about getting the t/s parameters on the thunps now that i think of it. That could be fun to see what it could do in blaubox.
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Posted By: DYohn
Date Posted: March 30, 2004 at 10:17 AM
You know, with as nice an enclosure as you are designing, it's a real shame to think you're planning to put CRAP speakers in it. Try these and you'll have a system that will rock and will last a long time.
Posted By: Disaster092
Date Posted: March 30, 2004 at 11:29 AM
Hmm, thats not too bad of an idea. Only problem is they dont say what size box is recommended and etc... The amp i will be using is a 200w x 4 so i could either wire it to take 100w to each speaker and use one channel, or find subs that will take 200w a piece, but i don't think i'm gonna find them unless i go to JL or something.
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Posted By: stevdart
Date Posted: March 30, 2004 at 12:10 PM
Here is the catalog page for those Dayton subs, which are high quality, by the way. https://www.partsexpress.com/pdf/catalog04/188pec03.pdf There is a good calculator here https://www.bcae1.com/ Scroll down along the right menu toward the bottom to get to 116-Speaker Enclosure Calculations. At the bottom of that page is a calculator. Plug in the parameters of the speaker and see what you get.
Posted By: DYohn
Date Posted: March 30, 2004 at 12:17 PM
Yea, Dayton makes excellent quality for the price. Comparable to woofers costing three times as much at least. The Quatro is their car audio line, rated at 180 WRMS for the 8" size.
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