# IDQ 10" v3 enclosure volume (sealed)



## Sillyboy (Sep 21, 2008)

So... I had intended to get the IDQ 10" v2 on super sale from woofersetc, but they apparently ran out  They hooked me up with a good deal on the v3, so I am going with that.

I wanted the v2 cuz it theoretically required less volume (according to the specs at ID http://www.imagedynamicsusa.com/pdf/iDQ10 D2 V.3 data.pdf)... so now I am trying to get a feel for how much it really matters.

Assuming ID stats are correct...
Qts .384
Vas 2.5 ft^3
Fs 25.528 hz

Vb of 1.0 ft^3: Qtc = 0.72 F3=47.0 hz Fc=47.76
Vb of .75 ft^3: Qtc = 0.80 F3=47.7 hz Fc=53.14
Vb of .50 ft^3: Qtc = 0.94 F3=50.6 hz Fc=62.53

So that is the basic numbers... that I don't actually understand... put here to make it easier to answer 

I would love to cheat towards as small as possible... but I don't have a great feel for the effect (trying to get some space back in my small trunk).

- "tightness" (transient response) is ... better or worse for higher Qtc (smaller enclosure) ?
- some polyfil can help me out... how much?
- given f3 diff of 3.6 doesn't seem uber extreme from .5 to 1 ft^3... how much am I gonna notice the reduced low end?

I should also mention I am not going to be driving it with a ton of power... about 225w.

Thanks for any comments.


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## Eric Stevens (Dec 29, 2007)

The IDQ10 V.3 sounds very musical with tons of bottom end in .9 cuft, in fact it almost seems to have too much on the bottom relative to the upper range and impact. 

I recommend the .75 cuft to balance it out. and if you are tight for space .5 cuft stuffed will give you similar response to the .75 cuft but not the same.

Dont worry about the F3 from WIN ISD it is based upon half space not an in car measurement. The -3 dB point in car will be at or below 20 Hz for .75 cuft or larger and not much higher for the .5 cuft. 

Not having a lot of power doesnt change the recommended enclosure at all. most of the volume increase happens in the first 100 watts, remember 3 dB for every doubling of power so going from 250 to 500 watts does the same as going from 1 watt to 2 watts.

Eric 
Image Dynamics


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## mvw2 (Oct 2, 2005)

Depends on the car. It is useful to understand what kind of gain response your particular car has. This will vary from vehicle to vehicle, so it does take a little bit of personal experience to figure out what you have to work with.

Think of it this way.

Sub has its own frequency response

Box shapes sub's frequency response some

Car cabin gain shapes sub's frequency response some

Sub + box + cabin gain = final frequency response

You sort of want to aim for flat for the final frequency response if you can. It's alright if you can't as EQing can take care of the spikes and dips. Not all cars are the same, so you'll need to do a little trial and error. If you can take the time, build an oversized test box, say 

I'm curious Eric's take on relative dampening with the smaller enclosures. Critically dampened is 0.5, which most folks shoot for the frequency response optimum of 0.707 which gives us the lowest F3. Higher numbers = less control, and some consider even 0.707 not ideal and prefer to gear their boxes more towards 0.6 as a compromise for control and low frequency extension and box size. For example, a final Q of 0.5 would require about a 3.5 cu.ft. box.  

I have no big personal take on this. Most of the time I build to the software "ideal" and most of my enclosures are ported and end up around 0.55-0.6 for the final Q as ported tends to be a little lower for the flat response. My personal thinking tends to lean me towards lower final Q values because it denotes control. However, it's not really that simple as Q is not static and varies anyways because the motor force and suspension varies. My own car also has very little cabin gain, and I for one do need to shoot for F3 values down in the 30Hz range to get a flat in-car response, hence my gearing towards ported boxes or large box sealed setups that will get me to 30Hz. That's just my car though. Your car will be very different.


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## Eric Stevens (Dec 29, 2007)

mvw2 said:


> I'm curious Eric's take on relative dampening with the smaller enclosures. Critically dampened is 0.5, which most folks shoot for the frequency response optimum of 0.707 which gives us the lowest F3. Higher numbers = less control, and some consider even 0.707 not ideal and prefer to gear their boxes more towards 0.6 as a compromise for control and low frequency extension and box size. For example, a final Q of 0.5 would require about a 3.5 cu.ft. box.


Q of a subwoofer system is used to describe the shape of the frequency response and the transient character of the system. Since the transfer function of the car has such a dramatic effect on the response you cannot think in the normal manner normally used and addressed for use in the home or other free space environments.

Another factor is the amount of static cone area has a large effect on the actual transfer function, so my box volumes recommendations vary from a single sub system to a dual or multiple subwoofer system. In single 10" systems I usually find it suiting my tastes at a system Q of .75 to .85 depending on the vehicle. For a pair of subs I will stick in the .85 range.

My personal favorite is IB with as much cone area as can be fit with some very low Q 15" or 18" subwoofers. This is an ultra low Q system with an ultra fast low Q driver that would look like it would have no output below 50 hz according any box program in other words an Fb of 70 or 75 hz.

Eric
ID


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## mvw2 (Oct 2, 2005)

But would it actually lack the low frequency output? Is there a different perception simply from the shear output that more low end is actually there than there really is? A lot of "bass" information doesn't exist in the lower frequency range. Even if a woofer did roll off at say 60Hz, it would still provide a good portion of the lower bass information, with authority, even if it did actually lack a few dB in output down lower. That lack could be EQed up too, so there isn't much loss.

I agree with the larger woofer idea. It has the benefit of nearly zero compression and the lower end will be unrestricted unlike many smaller driver setups that rely on a lot more excursion. Many of the lower compression drivers I've run do seem to naturally show a fuller and more open bottom end than ones ears are accustomed to, lacking or not in actual overall output. Also, the large cone area and very low excursion use means they are not sensitive to EQing bumps.

I guess my concern is with the idea of dampening. For example, if you put 2 10"s in the 0.85 cu.ft. box and get a final Q of say 1.0. At what point would this lack of dampening hinder driver performance? Wouldn't the sub be a bit sloppy in presentation? Or in the case of the low qts powerful motor setup, does the motor vastly overshadow any suspension shortcomings? If this is the case, are there any specific concerns one might have with the amp being used? In this type of setup, does the amp become influential in the control process?

Yeah, lots of questions, lol. Heck, this discussion should probably be in a new thread.


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## BEAVER (May 26, 2007)

mvw2 said:


> *I guess my concern is with the idea of dampening. For example, if you put 2 10"s in the 0.85 cu.ft. box and get a final Q of say 1.0. At what point would this lack of dampening hinder driver performance?* Wouldn't the sub be a bit sloppy in presentation? Or in the case of the low qts powerful motor setup, does the motor vastly overshadow any suspension shortcomings? If this is the case, are there any specific concerns one might have with the amp being used? In this type of setup, does the amp become influential in the control process?
> 
> Yeah, lots of questions, lol. Heck, this discussion should probably be in a new thread.


I believe he is refering to a final q in the .85 range, not a .85cft. enclosure.


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## Sillyboy (Sep 21, 2008)

Sweet, sounds like a .5 cuft enclosure w/ stuffing should at least... not suck 

Still curious about the effect of enclosure size on transient response (which I completely take to mean "tightness").


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## mvw2 (Oct 2, 2005)

Well, that can vary by sub. I can't say I've played too much specifically with box sizes and a single sub. I've found that the subs themselves sound very different from each other, and if you are looking for a particular sound type, only certain subs will fit that case well. For example, if you want something really light and crisp, you wouldn't buy a Alpine Type-R which is very smooth and more mellow and full. You would pick something more like Dayton's Reference sub which has a very light and airy behavior to it, squeaky clean as I call it. If you wanted something really punchy that can kick you in the chest, you look for something different. The box will influence their behaviors too, but the subs themselves start with their own type of sound. You sort of pick the sub that gives you the sound you want and then use the enclosure to shape the response.


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## lovenlife (Feb 3, 2008)

I have an IDQ v.3 and have played it in a .5 & .85 cu ft sealed enclosure and I just finished building a 1.3 ported per Eric's designs. I have to say that I personally I prefer the .85 cu ft sealed enclosure and would definitely heed all advice from Eric on any Image Dynamic product!


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## Eric Stevens (Dec 29, 2007)

mvw2 said:


> But would it actually lack the low frequency output?
> 
> You would be amazed at the amount of transfer function boost that happens on the bottom end in a vehicle.
> 
> ...


Beaver is right, my meaning was a system Q of .85. 

The non-linear compliance is the problem in higher Q sealed systems and this becomes more of a problem as the input power is increased obviously.

Longer excursion sub designs are more susceptible to the non linear compliance issue because they dont have the motor to over come the compliance because they have their total motor force spread over a much higher level of excursion.

When the Q of the system gets to high they dont get sloppy they start to ring, or overshoot. I call this boomy in a subwoofer. If it manifests itself in the lower register say 40 Hz and down they have rumble with no detail or texture, this is what happens with high moving mass subwoofers from a mass in motion cause and effect. It is all about finding an overall spectral balance, and then from there low distortion, linearity and output capability.

I prefer a motor dominated subwoofer as I stated previously which is what you get with a low Q subwoofer. But there is a lot more to it then just that but I cant type fast enough to get it all out here. 

A low Q motor in a high Q system doesn't have enough going on to out-weigh the effects of the high Q. But it might sound better than a high Q sub in a high Q system.

The amp will not be a concern unless it has a very low damping factor which is pretty much not the case for almost all decent amplifiers.

Eric
ID


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## jhirschkoff (Nov 28, 2009)

Eric,

I'm planning on puting a 10" sub into my 2007 Mini Cooper in the trunk facing up in a 0.8 ft3 enclosure. Which of your fine subs would you recommend for such a small vehicle. I'm looking for tightness forthe most part, but would like it to punch me in the chest when needed. I'm contemplating either a IDQ10V2.D2 or a IDQ10V3.D2 on an Alpine PDX-600.1 (gain turned down, obviously). Thoughts?

Thanks,
Joel


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## cognitive77 (Nov 4, 2009)

Just some personal feedback on my setup. I just had an IDQ 12v3 2ohm sub installed in a 1.0 cu ft sealed enclosure.

I've got an Alpine PDX-5 amp powering the sub with 416 watts on tap. I wouldn't describe the sound as punchy or loud. It has a very musical sound to it. It definitely doesn't rattle panels. While I am pleased with the sound, it would have been nice to have the headroom to get some "punch" out of it if I wanted to.


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## glidn (Apr 21, 2007)

well i have the v2 and the v3's.

v2 easily and would recommend 0.43ft3.
v3 i would not go under 0.85ft3 - 0.9ft3.

I found going any smaller no matter how much eq'ing i could not get this peak in the box.
Tried stuffing even wrapped the back of the sub with stocking. Still could not get it to sound nice.

So switched to the 0.9ft3, now it's balanced Wow bottom end and overall really like the sound.


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## Vancomycin (Mar 21, 2011)

I've used this site many times to learn what I can....thanks to all.

Eric, we spoke two days ago (doctor guy with Volvo sedan, same IDQ10v.3, 4ohms), thank you for your help. Very passionate about the subject - you spent 20 minutes on the phone with me! I'll do infinite baffle next time, my friend!

So we constructed a very solid SEALED box (with NASA precision), 0.97 cubic ft. 

Question please. Should I further add unnecessary bracing to reduce the volume to 0.92 cu. ft (yes, crazy noob) or should I just leave it. I want all the silicone to dry for several days, before putting in Image Dynamics sub. Will paint the outside of the box with fibreglass resin, etc. BUT...it's easier to make it smaller now, with the future option (perhaps unnecessary) of adding polyfill.

I listen to all sorts of music types, everything. Audison amps. I would like to hear the sub do its full thing at moderate and high volume levels, and, being a noob, don't want to sacrifice part of the sub's performance spectrum I may not (unknowingly) be placing appropriate emphasis on. Don't want my lack of knowledge to detract from the musical experience.

Regards to all in this thread.


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## BEAVER (May 26, 2007)

I'd leave it as is, provided it's sturdy enough as is. Just over 1 cube will give you a Q of .707, which most deem perfect.


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## Eric Stevens (Dec 29, 2007)

Vancomycin said:


> I've used this site many times to learn what I can....thanks to all.
> 
> Eric, we spoke two days ago (doctor guy with Volvo sedan, same IDQ10v.3, 4ohms), thank you for your help. Very passionate about the subject - you spent 20 minutes on the phone with me! I'll do infinite baffle next time, my friend!
> 
> ...


Use it as is and enjoy.

Eric


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## Vancomycin (Mar 21, 2011)

Great! Thanks very much guys!


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## Vancomycin (Mar 21, 2011)

OMG!!!
It sounds Incredible!
Absolutely love this Image Dynamics Sub.

Very nice product, thanks Eric.


My box....polyester resin gave nice final appearance...

ht.........tp://img651.imageshack.us/i/img9435w.jpg/


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## Techie (Mar 19, 2011)

I was wondering what people recommend for 2 idq10 v3's. Been trying to find some information lately and have found various different recommendations. I ordered the subs last week and I may not be able to build the box for another week or two. I've only built one box before and I used the manufacturer specs which had the exact sizes listed.

Also wondering if its recommended to use polyfill for these subs as well? Sounds like it couldn't hurt. I still have to spend some time reading up on box building techniques, but if anyone has advice building a box for 2 idq10 v3's -I am all ears. 

(Hope you don't mind me using this thread for it, seemed relevant enough though.).


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## Oliver (Jun 25, 2007)

ImageShack® - Online Photo and Video Hostinghttp://img651.imageshack.us/i/img9435w.jpg/


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## Horsemanwill (Jun 1, 2008)

what type of sound are you looking to get? what type of music what's the rest of your system compose of? how much room you got? how much power


sorry that came from the old mod mode from over at the old ID forum lol


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## Techie (Mar 19, 2011)

Horsemanwill said:


> what type of sound are you looking to get? what type of music what's the rest of your system compose of? how much room you got? how much power
> 
> 
> sorry that came from the old mod mode from over at the old ID forum lol



I would prefer to get some low bass out of it. I listen to a lot of dubstep and rock, sometimes a bit of rap. Rest of my system is Hertz HSK 165 XL's in the front, only getting 75w/side. I have plenty of room in my trunk, it's a 96 Civic. And currently have a 600w amp for the subs.


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## Horsemanwill (Jun 1, 2008)

then i'd say port it. when you get the subs in it willl be a tech sheet


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## Vancomycin (Mar 21, 2011)

Lots of good info out there, google, have fun with the build.

One site....
ht......tp://www.bcae1.com/spboxnew2.htm

I'm certainly not an expert, but some advice if making an MDF board...

Use 3/4" or 1" MDF.

****Have it perfectly cut (Home Depot will do it). 
Very important to final functionality.

Pre-drill holes for wood screws.

Use 1 1/2" X 1 1/2" wood for bracing internally.

Lots of wood glue and silicone sealant.

Just run quality wires out the back of box and seal thoroughly with silicone.
No need for fancy terminal post etc (all leak air).

Double the MDF for baffle (strength and when you pre-drill to install subs, the screws will not go all the way through the wood, and thus no additional air leak).

Can paint box with fibreglass resin to seal it better. Two thin coats are enough. Remeber to add hardener and use a roller. Gives final paint a glossy finish, or you can carpet it.


I would say the ideal size would be 0.94 cu. ft. for each 10" IDQ10V.3. That's what Eric from Image Dynamics said, and I agree  For a dual box, I would check other sources, but probably use MDF to separate two chambers of each sub. And brace them to reduce flexing.

*The published specs for this sub are erroneous, as pointed out elsewhere. Audiophile box is NOT 1.1 cu. ft. It's 0.94.* 
(0.9 -1.0, but not more IMO).

HIgh quality amp with clean RMS watts matching specs (350w each sub, AFAIK).


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## Mic10is (Aug 20, 2007)

Vancomycin said:


> Lots of good info out there, google, have fun with the build.
> 
> One site....
> ht......tp://www.bcae1.com/spboxnew2.htm
> ...


dude, I really have to know how you picked your username. you picked an antibiotic that is on the list of "last resort"..:laugh:


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## Techie (Mar 19, 2011)

Vancomycin said:


> Use 1 1/2" X 1 1/2" wood for bracing internally.
> 
> 
> Just run quality wires out the back of box and seal thoroughly with silicone.
> ...



I never thought of bracing it, but you brought up some good points I hadn't thought of. I had put a terminal post on my last box but always figured it was one of the weak points. I sealed the terminal with silicone the best I could, hoping it would give a good seal. 

I am not sure if I will make it one big chamber, or one chamber for each. Perhaps I should wait to see what kind of tech specs come with the subs when I receive them sometime in the next week.


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## Vancomycin (Mar 21, 2011)

Mic10is said:


> dude, I really have to know how you picked your username. you picked an antibiotic that is on the list of "last resort"..:laugh:


LOL!
I'm an M.D.
Look up VRE (vancomycin resistant enterococcus).


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## 000zero (Mar 12, 2011)

I currently have my IDQ10v3 in a sealed box of .60 cuft, the box is solid I built it myself using 3/4" MDF and I used some angle bracing on the inside, would my sub sound better if I stuffed the box?


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## Horsemanwill (Jun 1, 2008)

if u decide to go ported pm me an email addy and i'll send u a box design made by matt


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## ReticulatingPigeonElf (Sep 22, 2010)

Vancomycin said:


> I would say the ideal size would be 0.94 cu. ft. for each 10" IDQ10V.3. That's what Eric from Image Dynamics said, and I agree
> 
> *The published specs for this sub are erroneous, as pointed out elsewhere. Audiophile box is NOT 1.1 cu. ft. It's 0.94.*
> (0.9 -1.0, but not more IMO).


 What? Dang, and I just got done building an IDQ10 box shooting for 1.1cuft. I actually botched a couple cuts and had to plane down a few edges leaving the box a little smaller at about 1.01 cuft net. So maybe I should just add some extra material on the inside, like some mass loaded vinyl scraps to try and get it down to .94?


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## Vancomycin (Mar 21, 2011)

ReticulatingPigeonElf said:


> What? Dang, and I just got done building an IDQ10 box shooting for 1.1cuft. I actually botched a couple cuts and had to plane down a few edges leaving the box a little smaller at about 1.01 cuft net. So maybe I should just add some extra material on the inside, like some mass loaded vinyl scraps to try and get it down to .94?



Having owned/used it now for awhile, I would honestly say YES, reduce the internal size to 0.90 - 0.94 cu ft. Many here might say use it as is, but I would rec. you change it now, while it's easy. Maybe some 2X4" bracing, whatever. Good luck, my advice is meant in the most helpful way, it's a great sub, would like you to get the best out of it.


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## ReticulatingPigeonElf (Sep 22, 2010)

Vancomycin said:


> Having owned/used it now for awhile, I would honestly say YES, reduce the internal size to 0.90 - 0.94 cu ft. Many here might say use it as is, but I would rec. you change it now, while it's easy. Maybe some 2X4" bracing, whatever. Good luck, my advice is meant in the most helpful way, it's a great sub, would like you to get the best out of it.


Hmmm, now just to get exactly .05 worth of volume reduction. Guess this will come handy: Volume calculator - Math Central

UPDATE: looks like i'm going to need five pieces of 5 x 4.625 inch mdf...

seems like quite a bit of material. guess I'll try velcroing them to the inside walls since every corner already has battens and it wouldn't be practical to add more now that workable access to the inside has been diminished by the glued/screwed on baffle.


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## minbari (Mar 3, 2011)

2x4 16" long would do it too


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## ReticulatingPigeonElf (Sep 22, 2010)

minbari said:


> 2x4 16" long would do it too


If I can find one lying around I'll cut two 8" lengths and use it instead - gonna be a pain cutting small little segments of mdf now that my old jigsaw broke and i'd have to use a cumbersome circular saw.

But really, how much does .05 actually effect the sub's performance? like what, -25 db at 50hz? lol. or better yet, +50 db at 10khz?

edit: wait a second, a 16" 2x4 is more like .074? Looks like I'd need more like a 10.875" 2x4.


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## minbari (Mar 3, 2011)

2x4 is actually 1.5" x 3.5" dont ask me why


performance wise, I cant see it making much difference.


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## ReticulatingPigeonElf (Sep 22, 2010)

minbari said:


> 2x4 is actually 1.5" x 3.5" dont ask me why
> 
> 
> performance wise, I cant see it making much difference.


:surprised: oh really? im guess it's a label that stuck with an old standard. 2x4 is much easier to say.

it'd be funny to be a stickler about that on a fast paced job site:

"joe, get me a 2x4 plank stat"

"2x4? where?"

"wtf, there's a bunch of 'em right over there in a stack on the pallet - hurry the F up, i gotta reinforce this ditch wall before it collapses!"

"nope, not seeing any 2x4s over there"

"Right there on the f#@$ing pallet jack!!! god damnit i cant hold this much longer!"

"well boss, what I'm observing on the pallet jack technically are not 2x4s - see in 1961, at a meeting in Scottsdale, Arizona, the Committee on Grade Simplification and Standardization agreed to what is now the current U.S. standard: in part, the dressed size of a 1 inch (nominal) board was fixed at 3⁄4 inch; while the dressed size of 2 inch (nominal) lumber was reduced from 1 5⁄8 inch to the now standard 1 1⁄2 inch. So as you see boss, a 2x4 is no longer..."

"OH MY G....." [CRASH]

"Boss? Hey boss?"​


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## minbari (Mar 3, 2011)

ROFL!

followed quickly by "your fired"


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## sunshinetom (Sep 2, 2011)

this topic is so great, i like it so much


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## Ray21 (Oct 19, 2009)

I don't think the .05 will make an audible difference when in the car.


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## ReticulatingPigeonElf (Sep 22, 2010)

Ray21 said:


> I don't think the .05 will make an audible difference when in the car.


omgomgomgomg are you suurrreee?!?? I'm so afraid my bass wont go wompity womp! :wreck:

jk, guess i dont really give an f any more. got what i got gonna be happy with it. :laugh:


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## ReticulatingPigeonElf (Sep 22, 2010)

Any idea how to tame a 50hz spike and/or tighten the bass impact? My box is 1.01 cuft net - perhaps adding the proposed .05 MDF to the inside of the box would help? My Bit Ten has like -10db or something at 50hz, and there's still a pretty good hump there.


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## tonesmith (Sep 8, 2011)

Well, since I have been thinking about getting 2 or 3 12"s of the ID variety (as soon as I sort out my HU issue) It seems like a good post to ask this.

ID, IDQ and ID Max. What would be the best combination for good output without sacrificing SQ. I want a sealed box, space is not an issue and the amp is a Zed Minotaur ([email protected] or 1000 @ 2 ohms) with the Ra processor.

Assuming price is not an option what would be the best combination?

I want the bass to cometh, but I also want to keep it nice and clean when the wife and kids are in the car.

LOL at drug of last choice for serious infections. Not at any hospital in the US!:laugh:


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## ReticulatingPigeonElf (Sep 22, 2010)

BEAVER said:


> I'd leave it as is, provided it's sturdy enough as is. Just over 1 cube will give you a Q of .707, which most deem perfect.


just over 1 cube gross or net?


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