Does the subwoofer have to be "free-air"?
02-08-07, 07:38 AM
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Does the subwoofer have to be "free-air"?
I have a SC400. I am replacing my subwoofer with a more powerful/newer one. Question is: do i have to replace it with another free-air speaker or can it be the "regular" kind... I am trying to keep it in my rear speaker platform.
02-09-07, 09:37 AM
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free air
Yes, I am using the Kicker 10". It sounds very tight and clean... Just keep in mind that if you are going to for the "Iwant everyone to hear my bass" sound, you probably will NOT get it this way. But if you want a tighter, deeper sound than the stock pioneer, then yes, you can definately get an improvement with a free air. I would recommend you get good qulity parts though... Like wires, amp, hi/low adapter(if you are using the stock headunit) and of course a good ole' dynamatting. That ****** works awesome! Anyway, I hope this helps!
Rock
Rock
02-09-07, 10:54 AM
#5
Zombie Slayer
I originally ran the sub off the stock Nakamichi amp and it was a marked inprovement over the stock sub, but it did need more power. I currently have a HiFonics Zeus that needs to be installed to power the whole system (replaced all other speakers with MB Quart).
Here's a pic or 2 from the install.
Old sub.
New sub test (no baffle). You can see there is no way it was gonna fit without opening the hole.
Cuts made to begin opening the hole.
From the trunk.
That's all I have in my gallery. Lost the rest.
02-09-07, 01:48 PM
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I'll be the dissenting opinion on this topic. No, the sub does not have to be labeled "fee-air". That's just a marketing label like "car sub" and "home sub". It's all in the Theile/Small parameters. Mounting the sub in the rear deck is just like mounting the sub in an extremely large sealed box. The larger the box, the less effect it will have on the Qtc of the system. If your sub has a low Qts, then the Qtc will be low. If the sub's Qts is high, then the Qtc will be high. Different Qtc's will yield different response curves - link.
Combine the response curve with the natural cabin gain of the car and you will get your final response. As you can see, a low Qtc system will have a shallow roll-off. Sometimes that will be too much gain and make the final result sound boomy. But that can be overcome with proper tuning (parametric EQ and RTA software).
To get a close estimation of the Qtc of a driver, model it in Unibox using the size of the trunk as the size of a sealed enclosure. Another advantage of this software is determining the frequency where you will hit the sub's xmax (maximum linear excursion) based on input power. Now, sometimes going past xmax is not a bad thing. It depends on the sub's design. If the xsus (maximum limit of the suspension) is more than xmax, then you won't hurt anything. If the xmax and xsus are the same, then you are in danger of ripping a spider or crashing the voice coil into the back plate.
To sum this long post up, just get a quality sub with a decent xmax. If it sounds boomy, put some EQ on it.
-Robert
Combine the response curve with the natural cabin gain of the car and you will get your final response. As you can see, a low Qtc system will have a shallow roll-off. Sometimes that will be too much gain and make the final result sound boomy. But that can be overcome with proper tuning (parametric EQ and RTA software).
To get a close estimation of the Qtc of a driver, model it in Unibox using the size of the trunk as the size of a sealed enclosure. Another advantage of this software is determining the frequency where you will hit the sub's xmax (maximum linear excursion) based on input power. Now, sometimes going past xmax is not a bad thing. It depends on the sub's design. If the xsus (maximum limit of the suspension) is more than xmax, then you won't hurt anything. If the xmax and xsus are the same, then you are in danger of ripping a spider or crashing the voice coil into the back plate.
To sum this long post up, just get a quality sub with a decent xmax. If it sounds boomy, put some EQ on it.
-Robert
02-09-07, 04:29 PM
#7
Zombie Slayer
I'll be the dissenting opinion on this topic. No, the sub does not have to be labeled "fee-air". That's just a marketing label like "car sub" and "home sub". It's all in the Theile/Small parameters. Mounting the sub in the rear deck is just like mounting the sub in an extremely large sealed box. The larger the box, the less effect it will have on the Qtc of the system. If your sub has a low Qts, then the Qtc will be low. If the sub's Qts is high, then the Qtc will be high. Different Qtc's will yield different response curves - link.
Combine the response curve with the natural cabin gain of the car and you will get your final response. As you can see, a low Qtc system will have a shallow roll-off. Sometimes that will be too much gain and make the final result sound boomy. But that can be overcome with proper tuning (parametric EQ and RTA software).
To get a close estimation of the Qtc of a driver, model it in Unibox using the size of the trunk as the size of a sealed enclosure. Another advantage of this software is determining the frequency where you will hit the sub's xmax (maximum linear excursion) based on input power. Now, sometimes going past xmax is not a bad thing. It depends on the sub's design. If the xsus (maximum limit of the suspension) is more than xmax, then you won't hurt anything. If the xmax and xsus are the same, then you are in danger of ripping a spider or crashing the voice coil into the back plate.
To sum this long post up, just get a quality sub with a decent xmax. If it sounds boomy, put some EQ on it.
-Robert
Combine the response curve with the natural cabin gain of the car and you will get your final response. As you can see, a low Qtc system will have a shallow roll-off. Sometimes that will be too much gain and make the final result sound boomy. But that can be overcome with proper tuning (parametric EQ and RTA software).
To get a close estimation of the Qtc of a driver, model it in Unibox using the size of the trunk as the size of a sealed enclosure. Another advantage of this software is determining the frequency where you will hit the sub's xmax (maximum linear excursion) based on input power. Now, sometimes going past xmax is not a bad thing. It depends on the sub's design. If the xsus (maximum limit of the suspension) is more than xmax, then you won't hurt anything. If the xmax and xsus are the same, then you are in danger of ripping a spider or crashing the voice coil into the back plate.
To sum this long post up, just get a quality sub with a decent xmax. If it sounds boomy, put some EQ on it.
-Robert
I can't argue with that explaination!!!
Fabulous info and welcome to the club!
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02-10-07, 07:21 AM
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Thanks. I just wanted to clear up some long held myths. I'm normally hanging out in audio and home theater forums including the Cult of the Infinitely Baffled which deals strictly with home audio installs.
Just to add a little more to my original post - If you use a dual voice coil sub, you can power one coil while adding a resistor to the other coil. This is called Resistively Damped Operation. In fact, Ascendant Audio sold a line of subs called Atlas that had a 4 ohm voice coil that was meant to receive power from the amp and a 2 ohm voice coil that was meant to be shorted, left open or have a resistor inserted. They were nice enough to publish the T/S parameters for all three configurations.
I'll be an "official" member when my ES-350 is delivered in a couple of weeks.
-Robert
Just to add a little more to my original post - If you use a dual voice coil sub, you can power one coil while adding a resistor to the other coil. This is called Resistively Damped Operation. In fact, Ascendant Audio sold a line of subs called Atlas that had a 4 ohm voice coil that was meant to receive power from the amp and a 2 ohm voice coil that was meant to be shorted, left open or have a resistor inserted. They were nice enough to publish the T/S parameters for all three configurations.
I'll be an "official" member when my ES-350 is delivered in a couple of weeks.
-Robert
02-10-07, 10:31 AM
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If ur looking for some good subwoofers that would be good for IB setups look up the Image Dynamic Products. www.imagedynamicsusa.com
02-15-07, 06:48 AM
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In case anyone was on the fence about upgrading their IB sub, TC Sounds has just released a limited amount of their overstock 10" TC 7's. The Thiele/Small parameters make it a perfect fit for a rear deck install.
If you aren't familiar with TC Sounds, they are the build house for sub marketed by Eclipse, Aerial Acoustics, Stimpson Vodhanel Sound (SVS) and many other high end companies. I have no affiliation with the company other than being a very satisfied customer over the years.
-Robert
If you aren't familiar with TC Sounds, they are the build house for sub marketed by Eclipse, Aerial Acoustics, Stimpson Vodhanel Sound (SVS) and many other high end companies. I have no affiliation with the company other than being a very satisfied customer over the years.
-Robert
02-15-07, 07:16 AM
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go with a non free air, and it will sound like crap. no long post for me, just the fact that many have gone the regular route and wished they hadnt. i am not saying rob isnt correct, he is, but do you know enough about the system q and what to look for? probably not if you had to ask in the first place (that is NOT a slam BTW). many shops will tell you it is ok but they dont deal with free air very often so they are some what out of the loop "I" think. i did a free air install with 3 12's and about 1500 watts and loved it There is a thread in the forum. good luck.
http://sr1.clublexus.com/forums/showthread.php?t=241082
http://sr1.clublexus.com/forums/showthread.php?t=241082
Last edited by okiaristo; 02-15-07 at 07:22 AM.
02-15-07, 07:44 AM
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Like okiaristo said, if you don't want to do the research then get something that is marketed as free-air or IB. The TC-7 I linked to should work great. The Qts is almost .6 and the Fs is 30hz. Modeling this in Unibox, it will not be a bass heavy monster. It should give you a flat frequency response down very low. The 18mm xmax is more than adequate. The parameter that jumps out at me is xmech of 37mm. That means you don't have to be careful with this sub. If you over power it, it will be almost impossible to destroy.
-Robert
-Robert
02-15-07, 08:35 AM
#14
if you are dead set in leaving it in the stock location, there are options...
all of which take some fabrication...
1) build a small sealed box in place - this would ultimately prove difficult to get enough airspace to work and still fit in the area provided...
2) build a aperiodic enclosure (a what???)
an aperiodic enclosure would definitely be my choice if I was wanting to keep a 10" sub in the stock location, and get more performance from it than an IB (free air) acting sub would do... an aperiodic enclosure needs to be just big enough to enclose the rear of the sub, so space wouldn't be a problem... well, how does it work you say - if you aren't familiar with aperiodic enclosures, they are basically an enclosure with a vent in them - in this vent, there is fiberglass mat sandwiched between two screens of wire mesh... the amount of fiberglass insulation sandwiched between the two screens is what controls the airflow, and ultimately the damping of the subwoofer... it basically makes the sub think it's in a box, and you get to choose the size of the box by changing the amount of fiberglass insulation... the beauty of this, is that the "enclosure" can also be built over the sub, you only need enough room between it and the sub to account for excursion... it's a really cool idea, and back in the day, I once built a box that utilized this, and it sounded great... it's a little odd, but works really well...
more info can be found here: http://www.subwoofertools.com/portal...13&ContentID=5
all of which take some fabrication...
1) build a small sealed box in place - this would ultimately prove difficult to get enough airspace to work and still fit in the area provided...
2) build a aperiodic enclosure (a what???)
an aperiodic enclosure would definitely be my choice if I was wanting to keep a 10" sub in the stock location, and get more performance from it than an IB (free air) acting sub would do... an aperiodic enclosure needs to be just big enough to enclose the rear of the sub, so space wouldn't be a problem... well, how does it work you say - if you aren't familiar with aperiodic enclosures, they are basically an enclosure with a vent in them - in this vent, there is fiberglass mat sandwiched between two screens of wire mesh... the amount of fiberglass insulation sandwiched between the two screens is what controls the airflow, and ultimately the damping of the subwoofer... it basically makes the sub think it's in a box, and you get to choose the size of the box by changing the amount of fiberglass insulation... the beauty of this, is that the "enclosure" can also be built over the sub, you only need enough room between it and the sub to account for excursion... it's a really cool idea, and back in the day, I once built a box that utilized this, and it sounded great... it's a little odd, but works really well...
more info can be found here: http://www.subwoofertools.com/portal...13&ContentID=5
02-15-07, 08:28 PM
#15
Thanks. I just wanted to clear up some long held myths. I'm normally hanging out in audio and home theater forums including the Cult of the Infinitely Baffled which deals strictly with home audio installs.
Just to add a little more to my original post - If you use a dual voice coil sub, you can power one coil while adding a resistor to the other coil. This is called Resistively Damped Operation. In fact, Ascendant Audio sold a line of subs called Atlas that had a 4 ohm voice coil that was meant to receive power from the amp and a 2 ohm voice coil that was meant to be shorted, left open or have a resistor inserted. They were nice enough to publish the T/S parameters for all three configurations.
I'll be an "official" member when my ES-350 is delivered in a couple of weeks.
-Robert
Just to add a little more to my original post - If you use a dual voice coil sub, you can power one coil while adding a resistor to the other coil. This is called Resistively Damped Operation. In fact, Ascendant Audio sold a line of subs called Atlas that had a 4 ohm voice coil that was meant to receive power from the amp and a 2 ohm voice coil that was meant to be shorted, left open or have a resistor inserted. They were nice enough to publish the T/S parameters for all three configurations.
I'll be an "official" member when my ES-350 is delivered in a couple of weeks.
-Robert
The problem with a typical non-"free-air" sub is that the average guy doesn't know how to do the analysis and thus is very likely to over extend the suspension and/or fry the thing he puts in there. (Any sub that can handle power and is less compliant will usually not be "fryable", but that says little about the sound quality.)