What is wrong with my setup?

[ph7ryan]

Hi,

I bought an fi q 12" a few months ago, and it is powered by a audioque 1200d. Now I know this is not bad equipment at all, but I must say, I am not very impressed. It is not very loud at all, and it doesn't even feel broken in when I press into it... VERY stiff, but it plays at full volume probably half the time.... All the way up until the clipping light from the amp remote blinks, then back a hair until no more clipping. And for a subwoofer name "quality series" it is not very accurate with the hits. The only "non-professional" components of the system that I could think of are:

I built the box. I didn't have the outsides match up too well because I had a crappy small table saw, and had to eyeball the cuts (although the inside is very lined up)... The box is sealed inside and out however, and even the wires are through a drilled out hole and silicone sealed. The box is a simple cube shape, little wider than tall, but 1.16ft3... The sub takes up .16ft3 so it would be 1ft3 after the sub displacement. The ratings for the sub are like .8ft3 to like 1.6ft3 I think, so I am a little smaller than the middle but still in the range...

The RCA's are from the output of a Jensen Power 760 amplifier, which is not a very high end amp, but at about half gain, theres not much distortion at all...

The headunit is actually a carpc. I tried putting a high end PCI audio card in (107db s/n), but apparently it takes too much power because the computer will not turn on with it... I believe that the signal to noise ratio of the onboard audio is like 86 db I think... not horrible, but not great either...

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[dragnix 5,000+ posts]

so you have RCA input into the Jensen amp then output to the audioque amp?

 

[ph7ryan]

so you have RCA input into the Jensen amp then output to the audioque amp?

that is correct... onboard audio of computer to Jensen Amp, to audioque.

 

[dragnix 5,000+ posts]

are you doing that because you only have 2ch. of audio preouts on your soundcard and needing 4ch for amplification? Somehow, that doesn't seem ideal to me though. I'm assuming the jensen is powering your front stage of course.

 

[ph7ryan]

are you doing that because you only have 2ch. of audio preouts on your soundcard and needing 4ch for amplification? Somehow, that doesn't seem ideal to me though. I'm assuming the jensen is powering your front stage of course.

yes. There is a way to make like the in-line port and microphone ports "out" channels because it is like "Realtek HD audio" or some crap. I may go grab a 3.5mm to RCA splitter and try that today... and yes the Jensen is there to give sufficient power to my door speakers, because obviously the computer output is un-amped and so I needed something cheap. Turns out that about 60w at the doors with the gain turned down, quality is not bad at all, and the "temporary amp" may be permanent. The only thing that would sway an upgrade would be if I happened to come across $200 to put down towards the AQ 4x90.

Also, power to the AQ and the Jensen are both 4 gauge wire. Each has a separate kit. Jensen has a Kicker wiring kit, and the audioque has a knuconceptz kit.

I appreciate the help, seriously. Thank you.

 

[dragnix 5,000+ posts]

let's try to go ahead and eliminate the obvious things here. What are your xovers crossed at on the LPF of the audioque? I made the mistake of turning mine down too low before. RCAs...are they plugged in correctly? Loose speaker wires perhaps? Or perhaps the output voltage on your carputer is so low that it's not sufficiently providing power for the amp to make power, even at clipping...Idk, just some thoughts that popped up in my head that perhaps you can look in to.

 

[ph7ryan]

sounds like a plan... I will go out today after school and check the voltage at the rca's and the settings on the amp are what they should be... I can't remember where, but I felt like it clipped all the time, so I went on the internet and looked up what the settings should be... I found some thread where Dave i think, or whoever owns audioque, personally stated the settings the amp should be at... I will try and find the thread, but I wanna say the LPF is like 80-100 I think? Does that sound right?

Speaker wires should be solid inside of the box... I will retighten the ones from the amp out though...

RCA's are all of the way in, and the speaker doesn't make any noises when I wiggle them... I am thinking it is maybe the box because the subwoofer doesn't feel broken in yet... its just very stiff, and I don't know if that is just a quality of a sealed box or if it isn't broken in yet but either way, it is much stiffer than it would be to push in any other sub...

 

[dragnix 5,000+ posts]

LPF should be around 80-100, so you're good there. The subwoofer will feel stiff inside the sealed box because basically when you push down there's no air escaping from the box (try pushing the same sub down in a ported box). If the sub is brand new then perhaps it does need to be broken in, so maybe let it plays for a couple of weeks and see if it gets better after that.

 

[Kangaroux 5,000+ posts]

If you have the sub in a sealed box don't expect it to be loud. If you want loud, stick it in a ported tuned to ~35hz you'll see much better results.

 

[ph7ryan]

I do have access to a bigger more professional quality table saw now, so I may take advantage of it while I still can. The Fs frequency for the sub is 33.9 Hz... does that mean that is the lowest it will hit? so I should port it to 34-35hz right? Will I loose any quality (if it is even there) from tuning up at like 34-35 rather than like 32 or 33?

Also, should I do a longer narrower circle port, or a shorter wider port... or even slot port it... I heard that the longer and narrower port will make it act more like a sealed box than the wider shorter port... and I also heard that a circle port with a flared end sounds better than a slotted port or a square port.

Thanks for the help guys.

 

[Liquid Bass 10+ year member]

First the reason the sub feels stiff is because it is in a sealed box. And second you should build a ported box if you want more output