Audio Primer Sub Question
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Audio Primer Sub Question
Hi Percy/Mean Gene,
Following the free air sub thread and I have a question or two. The Primer seems to indicate that the big difference between a free air replacement sub size is that a 10" drops in from the top while a 12" bolts up from the bottom. Is that correct? No major surgery with either size just mounting location difference? In addition, Percy mentions using foam board as a spacer for a 12 from the under side. Would that mean that the sub eventually makes metal to metal contact and the foam board is a crushable gasket. With the vibration issue from a sub, and the attendant squeaks, it seems like it should really be bolted down firmly, I am a little confused on the purpose of the foam board. Also, I am getting more comfortable with the thought of a sub in a box. A 10" seems to get around a .66 cu ft sealed enclosure which is fairly compact and unless you are in to advertising your sub, I am beginning to think it would look better too. Is there some big mystery or do you bolt some angle to the box and velcro it to the underside of the rear deck? JUST KIDDING, OK so you have to use some bolts, but is that it. The $1200 question is if I use a 10 in a box, can I still mount a MC 446 to the back side of the seat - any thoughts?
Following the free air sub thread and I have a question or two. The Primer seems to indicate that the big difference between a free air replacement sub size is that a 10" drops in from the top while a 12" bolts up from the bottom. Is that correct? No major surgery with either size just mounting location difference? In addition, Percy mentions using foam board as a spacer for a 12 from the under side. Would that mean that the sub eventually makes metal to metal contact and the foam board is a crushable gasket. With the vibration issue from a sub, and the attendant squeaks, it seems like it should really be bolted down firmly, I am a little confused on the purpose of the foam board. Also, I am getting more comfortable with the thought of a sub in a box. A 10" seems to get around a .66 cu ft sealed enclosure which is fairly compact and unless you are in to advertising your sub, I am beginning to think it would look better too. Is there some big mystery or do you bolt some angle to the box and velcro it to the underside of the rear deck? JUST KIDDING, OK so you have to use some bolts, but is that it. The $1200 question is if I use a 10 in a box, can I still mount a MC 446 to the back side of the seat - any thoughts?
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Hi Ron!
The gasket made from foam board is used as a spacer. If you look at the stock sub opening, you'll see that the opening has a bevel. I'm guessing that Toyota/Lexus used this to increase the metal strength at that location. If a speaker is bolted from under the deck (bottom mount) then, at least with the Vel, the cone will hit the beveled metal on any type of hard bass note, thus deforming the cone. Some of the other gaskets on subs are quite a bit thicker (JL?) so this may not be necessary. Best way to check is to CAREFULLY push up on the cone to see if it clears. If in doubt, just use the spacer. You really can't go wrong with a 2 dollar foam board spacer protecting a 1200 dollar sub.
The spacer is firm enough to ensure good contact with the metal. Haven't had any problems...and I use the system everyday!
My older setup had the Vel in a 1.5 cubic foot box, sealed. Since the sub was firing into the rear seat (I had to lower down the "pass through" for good output) I used the backside of the box for mounting the components. I decided against the box idea since the box itself weighed around 50 to 60 pounds. Always bottomed the car when I hit a large bump. The car was a '96 Grand prix with the 3.4 24v engine. Lots of problems!
Percy
The gasket made from foam board is used as a spacer. If you look at the stock sub opening, you'll see that the opening has a bevel. I'm guessing that Toyota/Lexus used this to increase the metal strength at that location. If a speaker is bolted from under the deck (bottom mount) then, at least with the Vel, the cone will hit the beveled metal on any type of hard bass note, thus deforming the cone. Some of the other gaskets on subs are quite a bit thicker (JL?) so this may not be necessary. Best way to check is to CAREFULLY push up on the cone to see if it clears. If in doubt, just use the spacer. You really can't go wrong with a 2 dollar foam board spacer protecting a 1200 dollar sub.
The spacer is firm enough to ensure good contact with the metal. Haven't had any problems...and I use the system everyday!
My older setup had the Vel in a 1.5 cubic foot box, sealed. Since the sub was firing into the rear seat (I had to lower down the "pass through" for good output) I used the backside of the box for mounting the components. I decided against the box idea since the box itself weighed around 50 to 60 pounds. Always bottomed the car when I hit a large bump. The car was a '96 Grand prix with the 3.4 24v engine. Lots of problems!
Percy
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From: California
Thanks Percy. Yeah, that does some to be a problem with enclosures. In order to be stiff enough, they add all that weight. Am I still correct in assuming that a 10" will drop in from the top and a 12" bolts up from the bottom without major surgery? A lot of this will be easier once I get into this and actually can see the areas I am talking about. Right now just getting ready to get ready.
Ron
Ron
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