Ok currently im using a Fi Q18 in an 8 cubic foot box tuned to 19 hz powered by a dayton 1000watt amp, I used the RE box designer program on their website and i dont think it worked out right because my bass peaks really high, maybe around 60hz.

Im looking for help from the home audio geniuses here because im not sure how to make this work out for me

i listen to everything but mainly hip hop. it will seldomly be used for movies. and im building dayton 8s right now. im looking for good musical response and excursion. the room will be about 20x30

any designs or ideas are much appreciated

Post up all the dimensions. . .box and port.

Did you try lowering the crossover point? I run my home subs from 50 Hz and down.

Brian

edit - and if it is mainly for music, I would tune the box higher. . .say 25 Hz

Edited June 15, 200817 yr by BKOLFO4

its 49" tall, 23" wide, 20"deep. the top and bottom are both 1.5" thick. Port is 21.5"x3.5"x51.75". theres 3 window frame shaped braces inside

the room i have it in right now is about 12'x10', would this affect it?

the sub is standing up tall, with the port on the bottom of the front baffle

Edited June 15, 200817 yr by johny24

I think a higher tune would help you out as well. 25 hz seems all right. With a tune as low as you have it, it almost acts just as a sealed box sometimes and doesn't give much of a peak above tuning. That room is fairly small so you may actually be seeing some room gain around 60 hz. If you tune higher I think you'll notice an increase in the bump right above tuning, which might help it be more even with 60 hz.

Also I agree that if your crossover is above 60 it's probably too high. lowering the crossover will help eliminate that bump as well.

thanks! sounds good guys

i dont really understand the crossover on the amp, its an HPSA-1000R by dayton audio

it has six knobs, the left 3 are highlighted under "EQ" and they are Freq (18-80), Bandwidth (0.1-1), and Level (-14.5 to +6). then the right 3 knobs are Phase(0-180), Freq(30-200), and then Gain(0-10)

i moved the box around the room and it sounds much better. but im not sure about the crossover on the amp, audibly the frequency knobs make no difference. so i must be doing something wrong

i have the 500 watt version of that amp. the 3 on the right are an EQ. Frequency is the center frequency for the EQ. Bandwidth is the width of the frequency curve affected by the EQ. I think a .1 makes the curve more skinny, so maybe only 55-65 hz are affected if you have the freq on 60. a 1 might make it affect 10-110. That's just an example, not saying those widths are accurate. Then level is the amount of cut or boost to the EQ curve.

On the left side the freq is the crossover. So that should have an affect on the sound. Phase and gain I'm sure you know.

On mine, I have the freq. at about 20 hz, bandwidth at .4, and level on 2 I think. Crossover at about 65, phase 0 and gain about 1/3 (obviously signal dependant).

Edited June 15, 200817 yr by KU40

The Three Knobs by the EQ section os for the parametric EQ. To change the X-over frequency, you will have to use the frequency adujustment that adjusts from 30 to 200. Lower that a bit.

And if it is too peaky, you can also use the parametric to your advantage. You can cut adjust the frequency on the EQ to the point where it peaks and then lower the level adjustment. The bandwidth determins how much around the center frequency is cut or boosted so you may have to play around with that a bit.

You could also do the opposite of what i said and boost the bottom end so that the low end has as much output as where it peaks. But be careful when EQing the low end because if you boost too much on the low end too much you risk reaching mechanical limits of the speaker. I'd just the peak and use the gain to get the desirable output.

I hope that makes sense. I Ramble on sometimes.

You beat me to it KU!

yeah winner!

I can't do anything right

im looking for good musical response and excursion.

Sealed. No question about it.

Others didn't mention it but that peak could be an 'inductance hump' in the frequency response. The driver's voice coil inductance is not listed on the Fi site but it is a common problem on high excursion, overhung drivers. I had a +10db peak at 55 hz with my TC-3000 subs. It is also a problem with the Dayton Titanic kits. That's why that amp has an internal jumper switch to counteract the hump. Check your owner's manual for Notch Filter Jumper.

If you want to properly set up your PEQ, then you need to measure the in-room response of your sub. All you need is a disc with proper test tones and a Radio Shack SPL meter. You can go more elaborate with an RTA but that costs a LOT more money to do it properly. It takes about an hour to measure the different tones and enter them into a free spreadsheet that will compensate for the uncalibrated meter and give you a response graph. The spreadsheet I use simulates a Behringer Feedback Destroyer with 12 bands of PEQ. To simulate changes, you would only use 1 band of EQ.

-Robert

Enclosure seems on the small side for HT. Recently did an 18" RL-P in 18+ cubes at 16.5Hz. My 15" RL-P's are in 10cubes each @ 19Hz and sound very good for music and AWESOME for HT.

Might be "peaky" due to enclosure size. How did you decide on that enclosure size/tune?