Free air/Infinite baffle sub choices?
03-04-2008, 06:35 PM
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Free air/Infinite baffle sub choices?
When I was heavy into car audio years ago there were several choices for free air/infinite baffle subs, but now I am having trouble finding any except the Kicker Comp line......are there other choices? This is for my daily driver which is a coupe with a trunk, and I want to get rid of my current sub box to get back what little trunk space the car has, I thought I could live without the trunk space, but I can't!!
Any suggestions?
Any suggestions?
03-04-2008, 07:54 PM
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Subs that will work well in infinite-baffle setups like yours won't always be labeled as IB drivers. Looking at a sub's specs, look for a high Qts, at least 0.5. Something approaching 0.65-0.7 is better. On the other side of that coin, there are a lot of manufacturers that will claim their subs will work in IB, but this isn't true. At least they won't work well. Look at the Qts. It tells all.
Rob
Rob
03-04-2008, 08:05 PM
#3
Le Mans Master
i really am impressed with my 15" dayton IB subs, i have them in a different application then what you're planning on doing but check them out.
there is also a website called 'home of the infinitely baffled' that will give you some more ideas
there is also a website called 'home of the infinitely baffled' that will give you some more ideas
03-04-2008, 09:17 PM
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Thanks for the info so far. 
Out of curiosity, I checked the specs of the 12" subs I have in the box right now, and they have a Qtc of 0.721, and a Qts of 0.42, so I guess they are not suited to an IB install situation. Should I also look for a sub with a higher Xmax spec?
Out of curiosity, I checked the specs of the 12" subs I have in the box right now, and they have a Qtc of 0.721, and a Qts of 0.42, so I guess they are not suited to an IB install situation. Should I also look for a sub with a higher Xmax spec?
03-04-2008, 09:31 PM
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They'll work, but a slightly higher Qts would work better. If a given sub has a recommended box size, then it's not going to work well in IB as a general rule.
03-07-2008, 04:59 PM
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Any sub will "work" in IB, it just depends on what you want your response curve to look like. The parameters only dictate the response of the speaker, not how you can install it. If it generates a response you like then it "works" great for your application. You can model responses all day long in WinISD if you want to check out how different speakers react to install types.
The reason people shoot for a sealed box QTC value of .7ish or higher is because of cabin gain. Sub frequencies in a car will experience some rate of gain due to the interaction with the car. This will be different for every vehicle, but if a rule of thumb is desired then a QTC of 0.7 and an average cabin gain will probably combine to yield a decently pleasing response. Not bloated on the bottom end, boomy or muddy.
For IB in a car, QTS ~ QTC. So a speaker with a QTS of 0.7 will sound much like a speaker installed in a sealed box with a QTC of 0.7.
Now, if you have access to parametric eq/shelving filters then any sub can have a decent response curve. This isn't the best way to go about things, but it can work.
Something else to think about... What range are you planning on the subs covering. In a corvette we have huge openings in the front doors. A nice 8" midbass driver can cover well down into the 50-60hz range no problem. If your subs are only playing 50hz and down the necessity of a QTC=0.7 style response is even less important. In fact, a lower QTS will allow them to be more efficient at these lower frequencies. It's not going to get louder necessarily, but it will get lower with less power required.
Anyway, I myself am running to 12" subs(qts = 0.35) IB in my Z06. They are running 50hz and down, mating with some SEAS L22 8's in the doors. Bass is deep and tight. Kick drums are punchy and it gets low without seeming strained. I'm a BIG fan of this set up. I've always run sealed boxes in the past (Round Solobaric, Infinity Perfect, Adire Shiva, JL W3s) and this is my personal favorite.
If you've already got the subs then try it out. If the response is not to you liking and EQ doesn't help then get some different ones. No reason not to at least see if they will work for your taste. It not like they will blow up, or the IB Police will come to your door and give you a Free Air Violation. Just be careful not to overdrive them on the low end. Low Qts speakers don't have the suspension stiffness to keep them out of trouble if you push them to hard. Sub-sonic filter is highly recommended!
One more thing. Interestingly, with the small cabin and trunk of my vette, the response of the subs is drastically different when the windows are up or down. Much louder down. I've noticed this before on cars but the effect is much greater on the vette than any other car I've ever owned. I don't know if it's car specific or install specific, but I figured it was worth mentioning. The current setup is the only one i've had in my vette.
The reason people shoot for a sealed box QTC value of .7ish or higher is because of cabin gain. Sub frequencies in a car will experience some rate of gain due to the interaction with the car. This will be different for every vehicle, but if a rule of thumb is desired then a QTC of 0.7 and an average cabin gain will probably combine to yield a decently pleasing response. Not bloated on the bottom end, boomy or muddy.
For IB in a car, QTS ~ QTC. So a speaker with a QTS of 0.7 will sound much like a speaker installed in a sealed box with a QTC of 0.7.
Now, if you have access to parametric eq/shelving filters then any sub can have a decent response curve. This isn't the best way to go about things, but it can work.
Something else to think about... What range are you planning on the subs covering. In a corvette we have huge openings in the front doors. A nice 8" midbass driver can cover well down into the 50-60hz range no problem. If your subs are only playing 50hz and down the necessity of a QTC=0.7 style response is even less important. In fact, a lower QTS will allow them to be more efficient at these lower frequencies. It's not going to get louder necessarily, but it will get lower with less power required.
Anyway, I myself am running to 12" subs(qts = 0.35) IB in my Z06. They are running 50hz and down, mating with some SEAS L22 8's in the doors. Bass is deep and tight. Kick drums are punchy and it gets low without seeming strained. I'm a BIG fan of this set up. I've always run sealed boxes in the past (Round Solobaric, Infinity Perfect, Adire Shiva, JL W3s) and this is my personal favorite.
If you've already got the subs then try it out. If the response is not to you liking and EQ doesn't help then get some different ones. No reason not to at least see if they will work for your taste. It not like they will blow up, or the IB Police will come to your door and give you a Free Air Violation. Just be careful not to overdrive them on the low end. Low Qts speakers don't have the suspension stiffness to keep them out of trouble if you push them to hard. Sub-sonic filter is highly recommended!
One more thing. Interestingly, with the small cabin and trunk of my vette, the response of the subs is drastically different when the windows are up or down. Much louder down. I've noticed this before on cars but the effect is much greater on the vette than any other car I've ever owned. I don't know if it's car specific or install specific, but I figured it was worth mentioning. The current setup is the only one i've had in my vette.
Last edited by TylerHerring; 03-07-2008 at 05:02 PM.
11-03-2011, 11:55 PM
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Hey TylerHerring,
I have stumbled onto your subject from web searching. I hope you are still around to answer my questions. I am interested in IB for the rear deck. I don’t own a Corvette. My sedan Maxima sure have a larger trunk than a Corvette. From searching I found most people in regard to RMS speaker and RMS amp, most would rather have higher RMS on speakers then an amp so that is getting me to think in that direction. My question is if a pair of 6.5” woofers or subwoofers (both seem to have similar spec) with Qts of .55 for the rear deck will it require higher RMS from the amp than woofer to push the woofer or it does not matter knowing that it is best to have at least Qts at 0.7?
I have stumbled onto your subject from web searching. I hope you are still around to answer my questions. I am interested in IB for the rear deck. I don’t own a Corvette. My sedan Maxima sure have a larger trunk than a Corvette. From searching I found most people in regard to RMS speaker and RMS amp, most would rather have higher RMS on speakers then an amp so that is getting me to think in that direction. My question is if a pair of 6.5” woofers or subwoofers (both seem to have similar spec) with Qts of .55 for the rear deck will it require higher RMS from the amp than woofer to push the woofer or it does not matter knowing that it is best to have at least Qts at 0.7?
Any sub will "work" in IB, it just depends on what you want your response curve to look like. The parameters only dictate the response of the speaker, not how you can install it. If it generates a response you like then it "works" great for your application. You can model responses all day long in WinISD if you want to check out how different speakers react to install types.
The reason people shoot for a sealed box QTC value of .7ish or higher is because of cabin gain. Sub frequencies in a car will experience some rate of gain due to the interaction with the car. This will be different for every vehicle, but if a rule of thumb is desired then a QTC of 0.7 and an average cabin gain will probably combine to yield a decently pleasing response. Not bloated on the bottom end, boomy or muddy.
For IB in a car, QTS ~ QTC. So a speaker with a QTS of 0.7 will sound much like a speaker installed in a sealed box with a QTC of 0.7.
Now, if you have access to parametric eq/shelving filters then any sub can have a decent response curve. This isn't the best way to go about things, but it can work.
Something else to think about... What range are you planning on the subs covering. In a corvette we have huge openings in the front doors. A nice 8" midbass driver can cover well down into the 50-60hz range no problem. If your subs are only playing 50hz and down the necessity of a QTC=0.7 style response is even less important. In fact, a lower QTS will allow them to be more efficient at these lower frequencies. It's not going to get louder necessarily, but it will get lower with less power required.
Anyway, I myself am running to 12" subs(qts = 0.35) IB in my Z06. They are running 50hz and down, mating with some SEAS L22 8's in the doors. Bass is deep and tight. Kick drums are punchy and it gets low without seeming strained. I'm a BIG fan of this set up. I've always run sealed boxes in the past (Round Solobaric, Infinity Perfect, Adire Shiva, JL W3s) and this is my personal favorite.
If you've already got the subs then try it out. If the response is not to you liking and EQ doesn't help then get some different ones. No reason not to at least see if they will work for your taste. It not like they will blow up, or the IB Police will come to your door and give you a Free Air Violation. Just be careful not to overdrive them on the low end. Low Qts speakers don't have the suspension stiffness to keep them out of trouble if you push them to hard. Sub-sonic filter is highly recommended!
One more thing. Interestingly, with the small cabin and trunk of my vette, the response of the subs is drastically different when the windows are up or down. Much louder down. I've noticed this before on cars but the effect is much greater on the vette than any other car I've ever owned. I don't know if it's car specific or install specific, but I figured it was worth mentioning. The current setup is the only one i've had in my vette.
The reason people shoot for a sealed box QTC value of .7ish or higher is because of cabin gain. Sub frequencies in a car will experience some rate of gain due to the interaction with the car. This will be different for every vehicle, but if a rule of thumb is desired then a QTC of 0.7 and an average cabin gain will probably combine to yield a decently pleasing response. Not bloated on the bottom end, boomy or muddy.
For IB in a car, QTS ~ QTC. So a speaker with a QTS of 0.7 will sound much like a speaker installed in a sealed box with a QTC of 0.7.
Now, if you have access to parametric eq/shelving filters then any sub can have a decent response curve. This isn't the best way to go about things, but it can work.
Something else to think about... What range are you planning on the subs covering. In a corvette we have huge openings in the front doors. A nice 8" midbass driver can cover well down into the 50-60hz range no problem. If your subs are only playing 50hz and down the necessity of a QTC=0.7 style response is even less important. In fact, a lower QTS will allow them to be more efficient at these lower frequencies. It's not going to get louder necessarily, but it will get lower with less power required.
Anyway, I myself am running to 12" subs(qts = 0.35) IB in my Z06. They are running 50hz and down, mating with some SEAS L22 8's in the doors. Bass is deep and tight. Kick drums are punchy and it gets low without seeming strained. I'm a BIG fan of this set up. I've always run sealed boxes in the past (Round Solobaric, Infinity Perfect, Adire Shiva, JL W3s) and this is my personal favorite.
If you've already got the subs then try it out. If the response is not to you liking and EQ doesn't help then get some different ones. No reason not to at least see if they will work for your taste. It not like they will blow up, or the IB Police will come to your door and give you a Free Air Violation. Just be careful not to overdrive them on the low end. Low Qts speakers don't have the suspension stiffness to keep them out of trouble if you push them to hard. Sub-sonic filter is highly recommended!
One more thing. Interestingly, with the small cabin and trunk of my vette, the response of the subs is drastically different when the windows are up or down. Much louder down. I've noticed this before on cars but the effect is much greater on the vette than any other car I've ever owned. I don't know if it's car specific or install specific, but I figured it was worth mentioning. The current setup is the only one i've had in my vette.
