thoughts on subs

[ncc74656 2]

my coworker just got in some Xtants. they are 10" and he is running 150W off a JL 5 channel amp and they sound quite nice, clear, linear, and smooth. not as loud as i would like but quite musical. I am running my home computer sub in my truck off my Viper 2500.1D in my truck right now while i decide on new subs. it is far more musical and flat than my SP4 was and while - at the time - i wanted to have ultra low and super loud i feel i have experienced that and wish to build a much more musical system.

the sub i have in my truck right now is this one, purchased when i was 16 and has been used for many years, it is in a 4.7 cubic box tuned to 35Hz and i want my new subs to have at least the same linearity as this one but with far more volume as my front stage drowneds it out atm and im not done rebuilding it yet: https://web.archive.org/web/20020605235040/http://www.vidsonix.com/vidsonix/PDS151S.htm

knowing this, i am considering buying 2 18" Fi Q's and building them in the recommended enclosure as per Fi.

what are your thoughts?

[Fi 4 life 0]

I love my 18" Q. Its fully loaded without high-Qts and I'm planning on adding another

[ncc74656 2]

i had a BL before and it was in a box tuned quite high so i had no low end. looking at the Q it has a MUCH larger Xmax than a BL does so it makes me think its going to get lower than a BL ever could. i understand the Q is designed for the best clarity and having 2 of them the extra cone area should be louder than a single SP4 i would think.

[Fi 4 life 0]

All depends on box. My newest box is tuned to 28.

[ncc74656 2]

my SP4 box is at 29hz and it gets CRAZY low but lacks the upper end. i was thinking of placing this sub in the middle of tuning (32-35) and then adding some of those subsonic earth quake boxes for 5-30hz (the ones that alpine made and that other companies make for theaters).

in either case the low tuned box just pulls to much out of the higher end and peaks the lows to much. im looking for a flatter response. given that i dont think any box could bring hte SP4 in line with what i want to do.

[Fi 4 life 0]

Use a box making software to see the predicted response.

[THX_Elite 26]

One of the most knowledgeable and truly SQ oriented guys on this forum has 2 Fi Q's and has had them for 3 years now.  He tells me they are the best investment in car audio he has ever made!

He will swear by them.  Once he sees your post, he surely WILL comment for you

 

I personally would also recommend them, although I have not heard them...I have been breaking in a Fi BL 12" and love it.  It get's LOW it gets LOUD, and still is quite musical even though im at 2.5^3 and 32hz.

 

I don't see anything nor have I heard anything about the Fi Q's that would or could disappoint you, for what your trying to accomplish!

Edited April 6, 2014 by THX_Elite

[lithium 358]

 

 

 in my truck right now while i decide on new subs. it is far more musical and flat than my SP4 was and while - at the time - i wanted to have ultra low and super loud i feel i have experienced that and wish to build a much more musical system.

 

if thats the case then you shouldn't be worrying about subs at all. i dont understand how this is your goal but you're talking about 2 18" subs. What are you trying to accomplish exactly, because it certainly isn't SQ so stop kidding yourself? 

[THX_Elite 26]

 

 

 

 in my truck right now while i decide on new subs. it is far more musical and flat than my SP4 was and while - at the time - i wanted to have ultra low and super loud i feel i have experienced that and wish to build a much more musical system.

 

if thats the case then you shouldn't be worrying about subs at all. i dont understand how this is your goal but you're talking about 2 18" subs. What are you trying to accomplish exactly, because it certainly isn't SQ so stop kidding yourself? 

 

this is true if you are considering 18's for sure...i missed that part somehow. I was thinking two 12's

[ncc74656 2]

more sound quality is exactly what im after. thats why im looking at the Q's. whats wrong with 18 over 12's? i have plenty of space for them.

[garychurch84 127]

IMO a lot more cone to move which would lower response

Edited April 6, 2014 by garychurch84

[THX_Elite 26]

imo it seems that two 18's would not be ideal for a SQ "theater" like experience in a truck cab

Edited April 6, 2014 by THX_Elite

[ncc74656 2]

so i should run 4 or more 10's then? i could easily fit 6 of them in the back. that would provide more cone area than the 18's

i have read many places that a sub is a sub, a 10 will move at exactly the same rate as a 18 when it comes to frequency responce. size of a woffer is secondary to other attributes. are we now saying that this is not the case? that an 18 will sound noticeably worse than a set of 10's?

Edited April 6, 2014 by ncc74656

[garychurch84 127]

[ncc74656 2]

so i could go with 5 12's or 3 15's to reach the same cone area as 2 18's and gain better frequency responce in the process? so i could go 3 dual 1 ohm and get about 1.5 ohm load.

is the frequency response really going to be that much better? it would be about 600.00 cheaper to go 2 18's when you factor in amps and sub prices.

Edited April 6, 2014 by ncc74656

[garychurch84 127]

so i should run 4 or more 10's then? i could easily fit 6 of them in the back. that would provide more cone area than the 18'si have read many places that a sub is a sub, a 10 will move at exactly the same rate as a 18 when it comes to frequency responce. size of a woffer is secondary to other attributes. are we now saying that this is not the case? that an 18 will sound noticeably worse than a set of 10's?

I'm. Not ssaying I'm right just an opinion

[///M5 2,833]

more sound quality is exactly what im after. thats why im looking at the Q's. whats wrong with 18 over 12's? i have plenty of space for them.

You have ZERO comprehension of what that means.  Your posts are so confused I am almost convinced you are just trolling...if I hadn't driven by your shop and seen your truck I'd be sure of it.

[///M5 2,833]

And for the 1 millionth time STOP focusing on equipment and focus on your install.  It is 1000% of the problem/cure and you ignore it.

[ncc74656 2]

i would think that a Q sub would blow a SP4 out of the water with linearity and response given that its designed specifically for that. my BL hit the high notes very well and that was an 18 witch is why i have no second thoughts about going with a 18 Q. the Q has more Xmax so that says to me that it can hit the lows better wich is what the BL was missing.

now if the sub is built well and has a strong enough motor should an 18 or 15 be able to reproduce just the same sound quality as a 10 or 12 if all else is equal? i understand the larger the cone the more force is required to move said cone but i am under the assumption that the 18 has that much stronger of a magnet to facilitate this. looking at Fi's website it would appear that the same magnet is used on 15 or 18 variants of the Q and the BL has a stronger magnet and yet less Xmax? the huge xmax on the Q really throws me as i would have thought it would be the other way round.

in either case i could do 2 15's to get louder than my 18 is now as it has more cone area and i "should" gain more frequency response over 2 of the same 18's. knowing the 15 i have now sounds very good in my setup but lacks the volume and perhaps a tidge of low end the 15 Q's may be the best option.

I have also read that the "size of a sub determines its audio quality" is generally a null rule when dealing with high end audio drivers. I have read of 18's being in sound quality competitions so this has lead me to believe that while perhaps smaller subs will edge ahead a bit on quality of audio and response, the 18's are not far behind (if at all).

The space i have in back, current setup, and cost all make me lean towards 2 18's as opposed to 3+ smaller subs. having said this if the 18's are truly going to be atrocious in audio quality then i will have to just build up the system to accommodate the smaller subs.

[ncc74656 2]

M5 i am not ignoring my install, i am rebuilding the front stage and have built different boxes for my SP4. install can not fix a sub that is designed for SPL over linearity and sound quality. given my SP4 is in pieces i am left to either rebuild it and continue to use it or sell it off and replace it with speakers that better fit what i am looking to do. in that regards i am looking into the Q's.

when i say i want more quality that is exactly what i mean. i want the audio to be less peaky, have a more fluid response so as that one part of the audio does not cancel out another. i want the subs to be able to reproduce there full frequency range and i do not require a sub tuned to 29hz, even in a 33hz box the SP4 has less than a flat response curve. my coworker who installed 2 10's in his car has a better transient response than my sub does (for obvious reasons of the SP4 being designed more for SPL) and thus i am looking to buy subs more suited to the application at hand.

as for the install of my current components i have new tweeters in the mail that have FAR better specs than my lower level alpines. I have 2 mid range speakers that will go in my door and am using Velcro right now to play with position and angle. I have sound absorbing backing coming for the inner doors/floor area and i have a couple sheets of dynomatt that im installing as i find panels that are vibrating. I am ditching the crescendos once i receive these new drivers and then ill be able to actually sit down and start tuning/playing with things. i have a 16 channel digital EQ with cross over network now that is not an old external POT audio control.

edit: on a side note, i had an argument with my boss and i swear to god im right about this but he's got me second guessing.... we were talking about cross overs and I thought an active cross over system is done at the preamp level and its considered active because you are actively using pots or digital processors to change things where as a passive system uses capacitors and inducers that sit on the amplified, speaker level outputs and its called passive because you don't change it once you set it. but i was told im wrong and MECP states that active cross overs are at the speaker level output and they are active because its the higher voltage side of the system. ???

Edited April 6, 2014 by ncc74656

[Fi 4 life 0]

Active means its being processed before the amp and passive is after

[lithium 358]

more sound quality is exactly what im after. thats why im looking at the Q's. whats wrong with 18 over 12's? i have plenty of space for them.

 

the point im making is that you dont need the output if you're looking for a balanced system. what you're trying to achieve with 18" Q's wont result in anything different then the sp4 you had before. 

[lithium 358]

my SP4 box is at 29hz and it gets CRAZY low but lacks the upper end. i was thinking of placing this sub in the middle of tuning (32-35) and then adding some of those subsonic earth quake boxes for 5-30hz (the ones that alpine made and that other companies make for theaters).

in either case the low tuned box just pulls to much out of the higher end and peaks the lows to much. im looking for a flatter response. given that i dont think any box could bring hte SP4 in line with what i want to do.

 

you got a giant peak in the low end due to the subwoofer/enclosure and the acoustics of a vehicle. either EQ out the peak or look to gain output from midbass (because that upper range that you're lacking is approaching midbass frequencies. 

[lithium 358]

so i should run 4 or more 10's then? i could easily fit 6 of them in the back. that would provide more cone area than the 18's

i have read many places that a sub is a sub, a 10 will move at exactly the same rate as a 18 when it comes to frequency responce. size of a woffer is secondary to other attributes. are we now saying that this is not the case? that an 18 will sound noticeably worse than a set of 10's?

 

you're right a 10 and 18 CAN have the same frequencies response. the 18 is just capable of more output. 

[lithium 358]

more sound quality is exactly what im after. thats why im looking at the Q's. whats wrong with 18 over 12's? i have plenty of space for them.

 

you're not looking for sound quality you're looking for output.  no one on the planet installs 18s for the sake of SQ. 

Edited April 6, 2014 by lithium