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This sub or that sub?

 

Bronze Member
Username: Souleraser

Post Number: 47
Registered: Feb-10
I know that JL's w7 model is aimed at SQ and so is the FIQ from Fi.

I've heard the 12w7 and sounds great, but I've never heard the FiQ.

Here is the question: If you could get a sub for free (FREE) which sub would you rather get, a w7 or a FiQ?

It will be for a SQ system and the sub will be powered by a JL slash 1000/1 amp.

Thanks guys.
 

Silver Member
Username: Skdooley

Roanoke, VA Usa

Post Number: 684
Registered: Oct-09
If you're going to run a JL amp and get a w7 for free, then get the w7. Its a great woofer and you'll have matching equipment. Be sure you set the gain on the 1000/1. 1k rms is the sub's peak rms rating.
 

Platinum Member
Username: Glasswolf

Lexington, SC USA

Post Number: 13502
Registered: Dec-03
I prefer the Q, myself. It's customizable to the application, and the motor design is newer, and highly linear. The W7 is a great sub, but it's also getting to be old. Then again, I don't really care if my equipment matches. I care more about the sound.
 

Bronze Member
Username: Souleraser

Post Number: 49
Registered: Feb-10
I've been thinking a lot about this and feel I should give Fi a try. I've heard some bad things about the Q though, like the tensils breaking and the sub's inefficiency at notes above 60hz, but I think Fi has fixed those problems on its new Q model. If I'm not mistaken the Heat Ring upgrade allows the sub to have better transition from low to high notes and visa versa.

Another thing is the weight of the sub. The Q12 weighs around 27lbs. I believe as opposed to the 12w7 which weighs a whopping 45lbs. Its nice to save some gas these days.

And last but not least the price of the subs. I can get a brand new 12w7 for $449.00 + tax. On the other hand I can get a FiQ12 and still have some money left to buy an enclosure for it for around the same price as the 12w7 sub alone maybe for even less.
 

Platinum Member
Username: Rovin

1 15 = 152.5 DBs ...Trinidad & T...

Post Number: 16272
Registered: Jul-05
if its for pure SQ look at the 12" idmax also - 20hz Fs ....
 

Platinum Member
Username: Glasswolf

Lexington, SC USA

Post Number: 13511
Registered: Dec-03
who would cross over a sub higher than 60Hz anyway??

:D
 

Silver Member
Username: Skdooley

Roanoke, VA Usa

Post Number: 688
Registered: Oct-09
If money is envolved then the Q is a better bargain. It does very well, plus it has more options when it comes to having to find an amp to power it.
 

Platinum Member
Username: Rovin

1 15 = 152.5 DBs ...Trinidad & T...

Post Number: 16276
Registered: Jul-05
[[[[[[[[who would cross over a sub higher than 60Hz anyway?? ]]]]]]]]]



lol i fully agree with u

in my earlier days of car audio i always used to have mine at 80 for that hard hitting bass but yrs after when i began to buy better subs that cud play lower & started to put my lpf at 50hz & my comps upfront to play from 50hz up that was a awakening ....music started sounding soooooooo much better & more tolerable for longer periods of playing , silly me didnt know what i was missing ...
 

Platinum Member
Username: Glasswolf

Lexington, SC USA

Post Number: 13516
Registered: Dec-03
now try setting the HPF on the comps at 100Hz, and the LPF on the sub at 50Hz. Let the roll off fill in the one octave gap
 

Silver Member
Username: Gcs8

Atlanta, Ga

Post Number: 475
Registered: Sep-09
i swear i heard you say a wile back to set at 50 lpf and 125 hpf.
 

Gold Member
Username: Jakeyplaysbass

St. Louis, MO / ASU

Post Number: 3793
Registered: Jul-05
100-125Hz is fine for the high pass.
 

Platinum Member
Username: Glasswolf

Post Number: 13524
Registered: Dec-03
if you want a 1 octave gap, you'd use 120HP and 60LP or 100HP and 50LP. You can play with the settings to see what works for you depending on the natural roll off of your components and EQing involved. Not all crossovers are continuously variable. Many used fixed selections, so you have to work with what ya got.
 

Silver Member
Username: Skdooley

Roanoke, VA Usa

Post Number: 691
Registered: Oct-09
Is there a reason for having an octave gap? I read over what Rovin had posted about having the LPF on the sub amp set at 50 Hz. It made sense and I had never thought about it (always had it at 80) and it definitely made a difference in the musical quality of the sub. I ran through a couple tracks I normally listen to and I noticed less "distortion" type sound on a few songs. I guess instead of trying to hit so many frequencies out of the sub, it now can focus on the lows, which is what a sub is meant to do. I set my HPF on my 4 channel amp at 50, to meet what the sub is at. After reading about the octave gap, I'm curious to know more.
 

Silver Member
Username: Rosrock

Michigan

Post Number: 134
Registered: Mar-09
pure sq look at the ssa icon 12 to
 

Platinum Member
Username: Rovin

1 15 = 152.5 DBs ...Trinidad & T...

Post Number: 16285
Registered: Jul-05
good to know somebody tried it & liked it ...imo at least in my wagon alot of that higher freq boomyness is eliminated when u set the lpf filter lower & u hear much more accurate tighter sounding bass

i have to do some reading about that 1 octave thing ...
 

Platinum Member
Username: Glasswolf

Post Number: 13541
Registered: Dec-03
well, the gap just allows the two speakers (midrange or midbass and the sub) to meet in the middle of their roll-offs.
If both speakers are set to begin rolling off at the same frequency, then you'll have two speakers playing upper freqs, and two subs playing sub-bass (as an example) but at teh XO point, say 80Hz, you now have 4 speakers playing 80Hz at full volume, which causes a warm spot, making the midbass freq range sound overly warm and "boomy." ( a lot like the old bazooka tubes used to when set to 80-120Hz XO)

If you set the HPF to 100H with a Q of 12dB/octave and set the LPF to 50Hz with an 18-24dB/octave slope (steeper on the subs to keep them tight and snappy and out of the upper frequencies where you have vocals) then half way between at say, 70Hz, you'll have your mids and your subs both down about -6 to -9dB, and combined, you'll have a nice smooth transition between the mids and subs.

That's why you leave gaps between each set of frequency ranges when setting crossovers.
 

Gold Member
Username: The_image_dynamic

San Diego, California

Post Number: 5737
Registered: Dec-06
... not to mention the 12dB per octave cabin gain below 100Hz.
 

Gold Member
Username: The_image_dynamic

San Diego, California

Post Number: 5738
Registered: Dec-06
I thought I would post a couple charts to help explain what Glass is trying to say. The top chart shows the frequency responses of a subwoofer, a mid-bass driver and a high frequency tweeter. Note the "skirting", or overlaps in frequency output, where each driver meets the next at it's rolloff. The bottom chart shows the "summed" output response taking into account the fact that whenever two drivers overlap each other in frequency, the result will be an increase in amplitude in that range. This is why the dips that were present at max amplitude where the drivers meet in the top chart, are flat on the bottom chart. This is an extremely important theory to learn and if you can rap your head around what is happening here it will help you greatly in your future audio adventures.

Upload
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Platinum Member
Username: Glasswolf

Post Number: 13552
Registered: Dec-03
ooo sexy! I think I see another page for my site coming here.. haha

also; this is the cabin gain mentioned above:
http://www.glasswolf.net/papers/xferfunct.html

The Effects of Cabin Gain in Car Audio

Have you ever wondered why car audio systems can have so much bass as compared to a home stereo system? The reason has to do with space. Your home has a lot of it and your car doesn't. Because there is so little space in a car the bass notes (which are long waves) build up inside the passenger area. To calculate the length of a sound wave you divide the speed of sound (in feet per second) by the frequency. At sea level, the speed of sound is approximately 1,127 ft/sec. For example, a 40 Hz note has a wavelength of approximately 28 ft (at sea level).

(speed of sound)/(frequency) = wavelength

OR

(1,127 ft/sec)/(40Hz) = 28.175 ft

Since the length of the average car interior (including trunk) is in the 12 ft range the 40 Hz note will be longer then the car's interior. This is why notes below 70-90 Hz (depending on the vehicle) will have a greater output than the rest of the frequencies. Once this magic frequency is reached, bass output will increase by about 12 dB/octave below that frequency. This phenomenon is called cabin gain or "transfer function". So a smaller vehicle will have a greater cabin gain and should be able to have greater low bass than a larger vehicle. This is true for identical subwoofer systems with identical power. However larger vehicles are able to fit more subwoofers and amplifiers and so can out produce a smaller vehicle with limited space.

The transfer function works well because human ears are less sensitive to low bass. This natural bass boost helps to compensate for this. It doesn't matter what type of vehicle you have, the cabin gain will still apply. It will just be at a lower frequency with larger vehicles and at a higher frequency with smaller vehicles. Firing orientation of the subwoofer system has no effect on the transfer function of a particular vehicle. You can face the woofers in any direction or place them anywhere in the vehicle and the gain will be the same because it is only dependent on vehicle size. This is not to say that firing orientation or woofer placement will not have an effect on the subwoofer system output. It certainly does but this difference is not attributable to the cabin gain.

Bottom line: The cabin gain or transfer function will increase the low bass in a car stereo system over that of a home stereo system. The smaller the vehicle, the greater the gain.
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