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Discussion Starter #1
Car: 96 Honda Accord 2 door
Subs: two 10" SSD subs bp options and copper coils
Amp: IA20.1
Rear battery: Deka 9a31
Box: 3 cubes net daily tuned to 34.3hz / competition tuned to 44.66hz
The front baffle will be facing the back seats and the port will be facing the driver side.








 

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Is this a first time build or something you do often?

Those look like some beefy subs for sure. I hope to crank up four Q18's tomorrow afternoon for a test run in the new HT room. They are tuned to 12.5Hz. I have always like sealed in my car, but I wouldn't mind giving a couple of Fi's a shot in a ported setup.
 

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Discussion Starter #3
I have done a sealed box for two Sundown SD-v1s, a ported box for a mj18-m for the home theater, a sealed single box for a 12" SSD, and a ported box for 4 sundown E8s. Let me know what you think. I know it doesn't look pretty. lol.
 

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Discussion Starter #4
If anyone is wondering about the front baffle not being flushed, trust me it is on the inside. It was just a little wider when I cut it. I used a lot of tite bond and clamped it tight together and then drilled screws to make sure.

And thats a crazy low tune on those Qs. Do you have a build log for them?
 

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Discussion Starter #5
just primed the box and routed the adjustable port plug and put a handle on it to allow easier changing.
 

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Sounds like you have done a few boxes, so this is just fun for you. It looks good to me, besides, it's going in a car, hidden from view and/or covered. :huh:

And thats a crazy low tune on those Qs. Do you have a build log for them?
Well... sort of... they are included in my HT build thread... starting at about this post. Those do not show the actual boxes which I don't think I ever took pics of yet. I really dropped the ball on taking pics from those you see to completion. Well... almost completion. I only lack getting everything setup properly right now.
 

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Discussion Starter #7
Well, I just put the first coat on the box and it looks 1000x better lol. I'll take some more pictures after the 2nd coat. I don't think it needs more than 2 coats. I also started running wires in the car too.
 

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Discussion Starter #8
Some update- I ran some wiring and am in the process of making something to hold the battery in place.

Also 2nd coat was put on and it looks great.




 

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Good stuff fellow guy from the Ville. I bet those Fi's will pound it out in an Accord. I like the port restricter. Good idea.


Sonnie,

I'd forgotten all about that big nasty Q18 build you were doing. That should just about cover your bass itch...:hsd:
 

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Discussion Starter #10
I will be attending a local competition if I can get everything ready for the 13th.
 

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Discussion Starter #11
so yea, I didn't get it done because I started work and get really sleepy when I get home lol.

well update. I only need to run the speaker wires now. I just bought a PM d3100 battery off of a friend of a friend. O and I upgraded to a kicker kx350.2 amp for the door speakers.
 

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Discussion Starter #12
Just got everything in for a mock set-up and it was nice. I had the port plug out and gain up about 1/4 of the way up subsonic at 30hz. It was clean and loud as hell. :) I am going to get a new head unit though so this might drag out longer lol. I will also get my friend to help me tune the amp with an oscope. I really want to hear the lows with the daily tuning plug in.
 

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Discussion Starter #13
well, the amp went up in smoke when we were testing so I just sold that off to someone that knows how to fix it because it is a great amp and is pretty pricey for a new one. I am going to be picking up an audiopipe AP-3000D. :)
 

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just my .02 i would stay away from the audio pipe piece and find an amp that will handle those drivers due to there mechanical structure ..... you are going to need an amp with a high dampning factor ...exp. with the tuned enclosure
 

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Discussion Starter #15
I already got it. The first time I saw it, I didn't even give it a 2nd look. However, after seeing a lot of car audio threads about these amps putting out rated power for the price, its unbeatable. There has been quite a few that have tested/ran these amps and they all have good things to say only. The only bad things are the source input voltage is only 5v which is low but my head unit has only 2.5v. The other thing is the signal to noise ratio is rather low as well but I would not have the amp's gain up high enough daily for it to matter. For SPL competitions, I could care less about the low signal to noise ratio.

Can you explain why I would need an amp with a higher dampening factor for my enclosure? I have little knowledge here.
 

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Loudspeakers have a mind of their own. You send them a signal and they add their own twist to it. They keep on vibrating after the signal has stopped, due to inertia. That ’s called "ringing" or "time smearing." In other words, the speaker produces sound waves that are not part of the original signal. Suppose the incoming signal is a "tight" kick drum with a short attack and decay in its signal envelope. When the kick-drum signal stops, the speaker continues to vibrate. The cone bounces back and forth in its suspension. So that nice, snappy kick drum turns into a booming . Fortunately, a power amplifier can exert control over the loudspeaker and reduce ringing. Damping is the ability of a power amplifier to control loudspeaker motion. It’s measured in Damping Factor, which is load impedance divided by amplifier output impedance. Let’s explain. If the speaker impedance is 8 Ohms, and the amplifier output impedance is 0.01 Ohms, the damping factor is 800. That’s a simplification. Since the speaker impedance and amplifier output impedance vary with frequency, so does the damping factor. Also, the impedance of the speaker cable affects damping. Thick cables (with low AWG) allow more damping than thin cables with (high AWG). The lower the amplifier’s output impedance, the higher the damping factor, and the tighter the sound is. A damping factor of 1000 or greater is considered high. As you might suspect, damping factor is most important at low frequencies, say 10 Hz to 400Hz. High damping factor equals tight bass.

- How It Works
How does an amplifier control speaker motion? When the loudspeaker cone vibrates, it acts like a microphone, generating a signal from its voice coil. This signal generated by the speaker is called back EMF (back Electro Motive Force). It creates a current, which travels through the speaker cable back into the amplifier output, then returns to the speaker. Since back EMF is in opposite polarity with the speaker’s motion, back EMF impedes or damps the speaker’s ringing. The smaller the amplifier output impedance, the greater is the effect of back EMF on the speaker’s motion. An amplifier with low output impedance short-circuits the back EMF, so the back EMF drives the loudspeaker with a relatively strong current that works against the speaker’s motion. When the speaker cone moves out, the back EMF pulls the speaker in, and vice versa

In short, the loudspeaker damps itself through the amplifier output circuitry. The lower the impedance of that output circuitry, the more the back EMF can control the speaker ’s ringing.

Which is very important part for controlling a high end subwoofer in a vented enclosure.
 

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Discussion Starter #17

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Discussion Starter #18
Well my buddy and I just tuned the amp and it was LOUD. It sounded great too on about 30hz bass music with the port plug in. The subs are wired at 4 ohms. My rear deck, roof, and truck false floor was rattling a LOT. I have to keep the floor from flexing so much because it is kind of loud. It interfered with the sound too. I didn't think it can get that loud really. Maybe, I'll take some videos later.
 

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Discussion Starter #19
I made some holes for the speaker wires to go straight out the box instead of the port because the amp's connections are on different sides now. I cannot wait to get this thing metered.
 

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nice build. good to see you are still making new projects.

bruno, nice post. i didn't know about damping so thanks for the lesson.
 
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