A little enclosure help

[escalade520]

Well I've got my IDQ12D2V3

T/S:
http://www.imagedynamicsusa.com/pdf/iDQ%2012%20D2%20v.3.pdf

Enclosure Specs:
5/8 inch (0.625) mdf
20 inches wide
20 inches tall
10 inch bottom depth
8 inch top depth

I know, not a lot of space to work with, but using Bassbox pro 6 I come up with 1.353 cu ft Vb, and 1.576 cu ft using a 4 inch round port 15 inches long, my F3 comes out to 36.81 Hz. Is this a good frequency to run the IDQ12D2V3?

Is this enclosure too small to vent? Should I keep it sealed at 1.5 cu ft? Or is that too big? I made a big mistake and chose to seal it at the last moment independently between two subs. The above dimensions are per sub.

If I should vent it, where should I mount the ports?

Could I use a passive radiator? If so, how big would I need it? I have a 20*20 foot print to work with...

and how low is the perfect tuning frequency?

also, when mentioning my box tuning frequency, should i quote the Fb in bassbox, or the F3 where it drops 3db?

which should i use? winisd or bassbox?

Really sorry for all the questions, but I sincerely appreciate all your guys' help. Thanks!

[60ndown]

just build a sealed box,

if you dont like it (and you probably will)

start thinking about porting.

[escalade520]

well considering I already provided you with specs of a sealed enclosure, and asked for help porting, then I assume I want to go ported...

[escalade520]

anything?

[Medicineman]

In what vehicle is this to be installed (i.e. how much cabin space)? Smaller cabin space = more cabin gain.

I can not tell from your post... are you running two drivers or one?

According to WinISD, a ported enclosure 1.4 ft^3 @ 37Hz will give you a 2db hump at 55Hz. It will be 3db down at 40Hz. Looks bad for SQ considering that cabin gain will cause an increase around 45-55Hz in a lot of vehicles.

A ported enclosure with QB3 alignment needs 2.4 ft^3 @27Hz. This will give you a flat response down to about 40Hz. It will be down 3db around 26Hz (excluding cabin gain).

If I should vent it, where should I mount the ports?In a mobile environment, I keep the port as close to the driver as possible for better coupling. In many home speakers, the port is placed in the back of the speaker to minimize port noises.

Could I use a passive radiator? If so, how big would I need it? I have a 20*20 foot print to work with...Unfortunately, I have never worked with passive radiators so I can't help you with this one.


and how low is the perfect tuning frequency?Depends on the driver and box volume. I have found that QB3 alignments give the best sound (more accurate/less ringing). A good EQ is needed to shape the frequency response to work with the specific install, however. If you can't eq, you can build the enclosure to the manufacturers recommendations and add polyfill or wood blocks to tune from there. Experimentation is the only way to find what works best for your install.

also, when mentioning my box tuning frequency, should i quote the Fb in bassbox, or the F3 where it drops 3db?
Tuning frequency will be Fb. It is best to quote box volume and tuning frequency together. Real world F3 will be determined by the install (cabin gain, position, etc).

which should i use? winisd or bassbox?Does not matter. They both calculate theoretical frequency response for low input signals. Real world power, cabin gain, and driver position will determine actual frequency response. The important thing is that you learn how your vehicle relates to these calculated responses. When you are listening from the driver's seat, does the calculated response match the actual response? Probably not!!

I know, not a lot of space to work with, but using Bassbox pro 6 I come up with 1.353 cu ft Vb, and 1.576 cu ft using a 4 inch round port 15 inches long, my F3 comes out to 36.81 Hz. Is this a good frequency to run the IDQ12D2V3?Judging from the driver specs and my experience with other subs, I do not think you could get good SQ with that size box ported. It would be loud but the SQ would suffer. Small (for the driver) ported enclosures just don't sound right to me, no matter what the tuning frequency or how much eq you apply. A sealed enclosure @1ft^3 will work very well for the .v3 subs for SQ.


I am running two IDQ D4v.3 in a full size Blazer. The max recommended enclosure is 1cu.ft per driver (sealed). I am using 2.2 cu.ft (both drivers combined) with a little over one pound polyfill in a sealed enclosure. I went with the large enclosure plus polyfill because I have so much cabin space to deal with. It gives me better bass extension in my application. I had to boost 20Hz by 6db and cut a good bit around 45-50Hz to get a flat "sounding" response to my ears. The subs are very accurate in this enclosure but start to sound a little unnatural above 55-60Hz (I notice this because my last sub was the squeaky clean Dayton Ref 12 HF). I hope to low pass mine below 50Hz, hopefully 40Hz, once I get midbass issues worked out.

[Medicineman]

I forgot to mention....
I have not experimented with porting the IDQ's because I wanted to go with the smallest enclosure size this time around. Two sealed IDQ's require less volume than one ported Dayton Ref 12HF (half the volume in fact). :mad:

BTW, after owning the IDQ's for about three months, I think the Dayton Refs are superior in every aspect except enclosure size and power handling/compression. Bass heads may prefer the IDQ for the greater excursion but for SQ the Dayton's rule.

[jj_diamond]

I forgot to mention....
I have not experimented with porting the IDQ's because I wanted to go with the smallest enclosure size this time around. Two sealed IDQ's require less volume than one ported Dayton Ref 12HF (half the volume in fact). :mad:

BTW, after owning the IDQ's for about three months, I think the Dayton Refs are superior in every aspect except enclosure size and power handling/compression. Bass heads may prefer the IDQ for the greater excursion but for SQ the Dayton's rule.

although i have no experience with Dayton subs, the highlighted section of your statement is far from true in reference to an IDQ10. actually quite the opposite. more SQ than deeebeeez in a sealed enclosure. that being said, i have no experience with either sub in a 12".

[azngotskills]

Any reason why you can go by their recommended ported enclosure specs :confused:

[Medicineman]

although i have no experience with Dayton subs, the highlighted section of your statement is far from true in reference to an IDQ10. actually quite the opposite. more SQ than deeebeeez in a sealed enclosure. that being said, i have no experience with either sub in a 12".
I was not comparing sealed vs. ported with that statement. I was comparing sealed IDQ vs. sealed Dayton Ref. The IDQ has 4mm more xmax and a little better power handling. End result is more output capability with the lowest notes.

Judging from the driver specs and my experience with other subs, I do not think you could get good SQ with that size box ported. It would be loud but the SQ would suffer. Small (for the driver) ported enclosures just don't sound right to me, no matter what the tuning frequency or how much eq you apply. A sealed enclosure @1ft^3 will work very well for the .v3 subs for SQ.
I guess you missed this statement ;)