should i get high QTS fi Q 15 sealed x2

[lordaoshi 1]

I have been searching all over the internet to find out about qts (never even heard of it before i was looking into Q's

this isn't my first system, i just never accounted for it before. it looks to me like it is highly dependant on what you are doing

fi q 15's have the cooling and spider upgrade options, that is it

i am going for sound quality with this build, dual fi Q 15 in a sealed enclosure measuring

~ 2.3 ft^3 per sub (after displacement and bracing of course)

each sub will have it's own rockford fosgate t-1500-1bd giving them ~1350watts @ 2 ohms (already had one and just bought a second off a friend, who said headroom was a bad thing)

they will be in the back of my subaru impreza outback sport hitting upwards (hatchback)

plenty of power from the vehicle 250+ amp ho alternator and 2 xspower d2700 batteries (leftover from before i got the new alternator)

all wire is 0awg excluding the distribution block which feeds 4 awg to each amp

i mainly listen to techno, rock, metal,rap, and hip hop

will the heat rings affect SQ if i get them?

and also will this system sound better with high or low QTS?

i read here that the high qts was for sealed only, so that's me. what does qts even mean?

please any information helps for either topic,

Edited May 11, 2010 by Lord Aoshi

[NB50 206]

Q Parameters---------Qms, Qes, and Qts are measurements related to the control of a transducer's suspension when it reaches the resonant frequency (Fs). The suspension must prevent any lateral motion that might allow the voice coil and pole to touch (this would destroy the loudspeaker). The suspension must also act like a shock absorber. Qms is a measurement of the control coming from the speaker's mechanical suspension system (the surround and spider). View these components like springs. Qes is a measurement of the control coming from the speaker's electrical suspension system (the voice coil and magnet). Opposing forces from the mechanical and electrical suspensions act to absorb shock. Qts is called the 'Total Q' of the driver and is derived from an equation where Qes is multiplied by Qms and the result is divided by the sum of the same.

As a general guideline, Qts of 0.4 or below indicates a transducer well suited to a vented enclosure. Qts between 0.4 and 0.7 indicates suitability for a sealed enclosure. Qts of 0.7 or above indicates suitability for free-air or infinite baffle applications. However, there are exceptions! The Eminence Kilomax 18 has a Qts of 0.56. This suggests a sealed enclosure, but in reality it works extremely well in a ported enclosure. Please consider all the parameters when selecting loudspeakers. If you are in any doubt, contact your Eminence representative for technical assistance

Taken from here. T/S Parameters explained - SSA Car Audio Forum

[Kanaworm$ 292]

Here is a good read!

The Subwoofer DIY Page v1.1 - Sealed Systems: Box Calculations

[///M5 2,833]

The biggest influence on SQ will be how you integrate those with your front stage. It is rather easy to get subs to sound good, not so easy to get your system.

[lordaoshi 1]

thank you so much bromo, i couldn't find anythign at all about T/S parameters that wasn't a forum discussion, so i will deffinitely go with the high Qts, option. everywhere else i read just commented on " how tight the suspension is"

that has cleared up so many things for me , i find it so hard to wade through what people say on other forums

now regarding

the heat ring. according to the Q enclosure recommendations thread pinned in this forum. it lets it play a little higher, i have rf punch 8's in my rear doors, and then about every other size available, 6.5's 5.25's and then assorted tweeters. if the heat ring doesn't do anything significant below about 60 hz where the low pass of the 8's kicks in then i will most assuredly pass

the 15's are solely to make the bass deep, rich, and loud. i am hoping to at least get 140 db

since a single q 15 ported can do 145

i am hoping two sealed can at least break 140.

any thoughts?

Edited May 11, 2010 by Lord Aoshi

[Sir-Lancelot 216]

Get the BL's.

[lordaoshi 1]

The biggest influence on SQ will be how you integrate those with your front stage. It is rather easy to get subs to sound good, not so easy to get your system.

i think they will work out great, i think my front stage already sounds amazing, alpine type x pro compontents in the front , rf p2 punch 8's in the backdoors along with 5.25 type r coaxials.

all the alpines are off a t400-4

the punch 8's share a t500-1bd

i am hoping the 15's will cover the lows better then my older ported infinity 1252rw's did.

and some days i like the bass to drown everything else out, that's when i make with my punch equalizer

Edited May 11, 2010 by Lord Aoshi

[lordaoshi 1]

Get the BL's.

i don't have room to build a big ported enclosure, my useable trunk volume for teh box is only about 6^ft total,

i had bad experience with ported subs before, maybe they were tuned too high but they were so peaky i was constantly adjusting the volume when listening to songs that had shifting bass

it was custom built and tuned to 33 hz and and anything below 30 couldn't be heard unless you head your ear to the woofer, and anything above 50 sounded just terrible.

anything between there was clean and loud though.

[NDMstang65 403]

I suggest getting a High Qts one if you plan on sealing the subs...thats sort of the whole point of having that options

[///M5 2,833]

the 15's are solely to make the bass deep, rich, and loud. i am hoping to at least get 140 db

since a single q 15 ported can do 145

i am hoping two sealed can at least break 140.

any thoughts?

Why do you ask about SQ and then "hope" to break 140. Counterintuitive and completely opposite goals...at least without discussion of a honking ridiculously huge and exciting front stage.

[lordaoshi 1]

Well i have done all spl in the past so i guess i am after a more ""SQL"" build i still like it loud, but i want it to sound GOOD loud not like bean night at a fat camp i will accept however loud it may be but i i can break 140db with a sealed box i will feel like i didnt make any really huge sacrifices