Added a sub!
10-08-2002, 12:31 AM
#1
Instructor
Thread Starter
Join Date: Aug 2002
Posts: 154
Likes: 0
Received 0 Likes
on
0 Posts
Added a sub!
My audio setup is now complete, thanks to this forum.
As you all know, I have been pondering the subwoofer replacement for some time now. I was planning to go with the Kicker RMB8 in the stock sub location, but feedback from this group (especially TopGum - thanks) led me to believe that I wouldn't be completely satisfied with the result.
I ruled out ANY sub in the stock location - there are no true subs that will fit without modifying the torsion bar, which I wasn't willing to do. It seemed that the only other alternative was a sub in the trunk. The custom installations (fiberglass) are very expensive, and I was opposed to a standard box as it would consume valuable trunk space.
The more I thought about it, I realized that I could afford to sacrifice some space in the trunk - after all, I use my TL-S mostly for commuting, and some local jaunts with the family. We have a Grand Cherokee for the longer trips.
So I headed down my local "trusted" audio/video shop (Magnolia Hifi) and checked out some subs and amps.
To make a long story short, I ended up with a Diamond Audio M610D4 10" sub, powered by an Xtant A3001T power amp. The Diamond sub is best described as "tight" and "musical" - I don't want boomy bass, but nice, crisp, "punchy" bass, as befits the alternative and classic rock that I listen to. The Xtant amp provides 150W RMS into the 4 ohm load of the Diamond Sub.
The sub was enclosed in a sealed MDF box. Both the sub and amp were installed in the forward part of the trunk, so it wouldn't interfere with access to the spare tire. The amp was mounted to the trunk floor. A "shelf" made out of MDF and covered in trunk carpet was then installed over the amp, and finally the sub enclosure was mounted to the shelf, above the amp. The stock sh**ty Bose sub was removed to "port" the sub into the cabin.
The installer (Scott) used the line-level and remote out for the stock Blose sub amp. He told me that all the folks in the shop got a good laugh when they saw the cheesy Bose amp!
The sub is mounted so that it can be easily removed via two bolts and a quick disconnect for the speaker wire, should I ever need to utilize the full trunk capacity.
The sub is installed on the right side of the trunk, and at first Scott had it pointed to the left; however, that setup resulted in some phase cancellation, so he pointed it to the rear, which worked better.
The result? A nice, tight bottom end (the music that is
) that is rarely boomy. It certainly added the "missing ingredient" to my system.
Now a question: the system sounds great when stopped or driving slowly (< 60). However, at higher speeds, and especially on rough pavement, the bass seems to get "lost". What is the best way to address that? If I turn up the bass on the HU the sound from the Polks is also affected. The installer suggested a more power amp. Is that a good option? Should I dynamat the entire doors (I used it around the speakers only) and/or the trunk? Or even consider a more powerful sub (like the Diamond Audio TDX series?
I'll take some pics and try to post them somewhere if anyone is interested.
As you all know, I have been pondering the subwoofer replacement for some time now. I was planning to go with the Kicker RMB8 in the stock sub location, but feedback from this group (especially TopGum - thanks) led me to believe that I wouldn't be completely satisfied with the result.
I ruled out ANY sub in the stock location - there are no true subs that will fit without modifying the torsion bar, which I wasn't willing to do. It seemed that the only other alternative was a sub in the trunk. The custom installations (fiberglass) are very expensive, and I was opposed to a standard box as it would consume valuable trunk space.
The more I thought about it, I realized that I could afford to sacrifice some space in the trunk - after all, I use my TL-S mostly for commuting, and some local jaunts with the family. We have a Grand Cherokee for the longer trips.
So I headed down my local "trusted" audio/video shop (Magnolia Hifi) and checked out some subs and amps.
To make a long story short, I ended up with a Diamond Audio M610D4 10" sub, powered by an Xtant A3001T power amp. The Diamond sub is best described as "tight" and "musical" - I don't want boomy bass, but nice, crisp, "punchy" bass, as befits the alternative and classic rock that I listen to. The Xtant amp provides 150W RMS into the 4 ohm load of the Diamond Sub.
The sub was enclosed in a sealed MDF box. Both the sub and amp were installed in the forward part of the trunk, so it wouldn't interfere with access to the spare tire. The amp was mounted to the trunk floor. A "shelf" made out of MDF and covered in trunk carpet was then installed over the amp, and finally the sub enclosure was mounted to the shelf, above the amp. The stock sh**ty Bose sub was removed to "port" the sub into the cabin.
The installer (Scott) used the line-level and remote out for the stock Blose sub amp. He told me that all the folks in the shop got a good laugh when they saw the cheesy Bose amp!
The sub is mounted so that it can be easily removed via two bolts and a quick disconnect for the speaker wire, should I ever need to utilize the full trunk capacity.
The sub is installed on the right side of the trunk, and at first Scott had it pointed to the left; however, that setup resulted in some phase cancellation, so he pointed it to the rear, which worked better.
The result? A nice, tight bottom end (the music that is
) that is rarely boomy. It certainly added the "missing ingredient" to my system.Now a question: the system sounds great when stopped or driving slowly (< 60). However, at higher speeds, and especially on rough pavement, the bass seems to get "lost". What is the best way to address that? If I turn up the bass on the HU the sound from the Polks is also affected. The installer suggested a more power amp. Is that a good option? Should I dynamat the entire doors (I used it around the speakers only) and/or the trunk? Or even consider a more powerful sub (like the Diamond Audio TDX series?
I'll take some pics and try to post them somewhere if anyone is interested.
10-08-2002, 09:13 AM
#2
Senior Moderator
iTrader: (2)
Join Date: May 2000
Location: where the weather suits my clothes
Age: 55
Posts: 27,921
Received 1,080 Likes
on
661 Posts
Ah the dreaded road noise cancellation.
I would definitely suggest Dynamatting the entire trunk, rear deck, underneath the back seat and all 4 doors. That should keep a lot of road noise out.
I would definitely suggest Dynamatting the entire trunk, rear deck, underneath the back seat and all 4 doors. That should keep a lot of road noise out.
10-08-2002, 10:11 AM
#3
Burning Brakes
Join Date: Apr 2002
Location: O.C., southern cal
Posts: 994
Likes: 0
Received 0 Likes
on
0 Posts
?I would definitely suggest Dynamatting the entire trunk, rear deck, underneath the back seat and all 4 doors. That should keep a lot of road noise out."
Just wondering, how much does Dynamat weigh? It seems like this would add significant weight. A unavoidable trade off?
Just wondering, how much does Dynamat weigh? It seems like this would add significant weight. A unavoidable trade off?
10-09-2002, 02:38 AM
#4
Pro
Join Date: Feb 2002
Posts: 698
Likes: 0
Received 0 Likes
on
0 Posts
Congrats egilsrud! Sounds like you're almost all the way to a complete system that you can live with. I don't have a lot of experience with subwoofers, so I'm sure others on the forum can give you better advice.
Is there any gain controls on the new subamp? It sounds like, at high speeds, that you need to somehow be able to turn up the gain of that amp without turning up the bass from the headunit which would overdrive the Polks. Give some thought as to how you might remotely accomplish that? Dynamat in the trunk would also help a lot... but as others have stated, it does weigh a lot. I've read in other threads, that when someone dynamats the entire trunk lid, it will no longer stay up and open by itself. The weight is too much for the torsion bars. I think somebody added some shock absorber type mod like the rods that hold open the front hood to compensate for the weight.
You could also maybe add some series "bass blocker" caps to all of the door speakers, so that when you turn up the bass on the headunit it predominently increases the bass to only the rear sub. The problem with this would be a lot of trial and error to come up with the proper value of cap. You MIGHT get lucky, but you'd probably find that you'd have to lose too much mid bass in the door speakers to achieve enough extra low bass gain from the subwoofer. But if you only need an additional 6db or so of bass to the subwoofer, this approach may just work fine. You could start to block bass frequencies to the door speakers at around 50hz-100hz and lower. This would gain you 3db at 100hz and 10-12db at 20hz. By gain here I mean that the BASS signal fed to the door speakers would be 3db-10db lower than what is being DIRECTLY fed to the subamp. Assuming you have enough overall gain left in the volume control of the headunit (and there's not a lot when driving the Polks) you could turn the bass up and then turn the volume up to compensate for the loss of bass to the door speakers. IN THIS MODE, you would now be feeding the subwoofer with MORE bass than it had before, while the door speakers have the same net result bass. This all depends upon the bass contour of the headunit control. Like I say it would take some trial and error, to see if this concept is feasible. But if you only need a slight more extra thump from the sub, it could just work... You wouldn't want to cut the bass to the doors too drastically or at too high of a frequency. So you'd have to experiment with cap values.
A 470uF/35volt or higher NON POLARIZED CAP in series with the 4ohm Polks would start a bass rolloff at 85hz. It would be down by about 3db at that point headed for a 6db/octave downward. In reality it actually takes several octaves to finally reach the true 6db per octave rolloff.
At the calculated "breakpoint" where the caps reactance equals the speakers impedance, you would be down by 3db. (with a 470uf cap and a 4ohm speaker, this is 85Hz)
AT ONE OCTAVE below the breakpoint (43.5Hz)you would be down by a total of 6.99db.
AT TWO OCTAVES below the breakpoint (21.75Hz) you would be down by a total of 12.3db.
AT THREE OCTAVES below the breakpoint (10.875Hz) you would be down by a total of 18.13db.
AT FOUR OCTAVES below the breakpoint (5.4375Hz) you would be down by a total of 24.1db.
So you can see that it takes about three or four octaves to finally reach the actual 6db per octave rolloff.
A 470uF cap might be a good place to start your experimentations. The larger value of cap you use, the lower the bass blocking frequency would begin... the lower value of cap you use would raise the frequency at which the cap starts to block the bass.
That's all I can suggest that's cheap and dirty... but it might work. I'm sure others may have better methods to solve your problem, but I'm sure it will cost a lot more to do things fully properly. The only other solution that I see, is to add a separate gain control to the subamp (you could place this in line from the headunit to the rear subamp and mount a pot somewhere in reach of the front console) That approach would probably work very well, but some behind the dash mods would be in order, etc. See what others suggest and weigh your options...
Good Luck!
Southbound
Is there any gain controls on the new subamp? It sounds like, at high speeds, that you need to somehow be able to turn up the gain of that amp without turning up the bass from the headunit which would overdrive the Polks. Give some thought as to how you might remotely accomplish that? Dynamat in the trunk would also help a lot... but as others have stated, it does weigh a lot. I've read in other threads, that when someone dynamats the entire trunk lid, it will no longer stay up and open by itself. The weight is too much for the torsion bars. I think somebody added some shock absorber type mod like the rods that hold open the front hood to compensate for the weight.
You could also maybe add some series "bass blocker" caps to all of the door speakers, so that when you turn up the bass on the headunit it predominently increases the bass to only the rear sub. The problem with this would be a lot of trial and error to come up with the proper value of cap. You MIGHT get lucky, but you'd probably find that you'd have to lose too much mid bass in the door speakers to achieve enough extra low bass gain from the subwoofer. But if you only need an additional 6db or so of bass to the subwoofer, this approach may just work fine. You could start to block bass frequencies to the door speakers at around 50hz-100hz and lower. This would gain you 3db at 100hz and 10-12db at 20hz. By gain here I mean that the BASS signal fed to the door speakers would be 3db-10db lower than what is being DIRECTLY fed to the subamp. Assuming you have enough overall gain left in the volume control of the headunit (and there's not a lot when driving the Polks) you could turn the bass up and then turn the volume up to compensate for the loss of bass to the door speakers. IN THIS MODE, you would now be feeding the subwoofer with MORE bass than it had before, while the door speakers have the same net result bass. This all depends upon the bass contour of the headunit control. Like I say it would take some trial and error, to see if this concept is feasible. But if you only need a slight more extra thump from the sub, it could just work... You wouldn't want to cut the bass to the doors too drastically or at too high of a frequency. So you'd have to experiment with cap values.
A 470uF/35volt or higher NON POLARIZED CAP in series with the 4ohm Polks would start a bass rolloff at 85hz. It would be down by about 3db at that point headed for a 6db/octave downward. In reality it actually takes several octaves to finally reach the true 6db per octave rolloff.
At the calculated "breakpoint" where the caps reactance equals the speakers impedance, you would be down by 3db. (with a 470uf cap and a 4ohm speaker, this is 85Hz)
AT ONE OCTAVE below the breakpoint (43.5Hz)you would be down by a total of 6.99db.
AT TWO OCTAVES below the breakpoint (21.75Hz) you would be down by a total of 12.3db.
AT THREE OCTAVES below the breakpoint (10.875Hz) you would be down by a total of 18.13db.
AT FOUR OCTAVES below the breakpoint (5.4375Hz) you would be down by a total of 24.1db.
So you can see that it takes about three or four octaves to finally reach the actual 6db per octave rolloff.
A 470uF cap might be a good place to start your experimentations. The larger value of cap you use, the lower the bass blocking frequency would begin... the lower value of cap you use would raise the frequency at which the cap starts to block the bass.
That's all I can suggest that's cheap and dirty... but it might work. I'm sure others may have better methods to solve your problem, but I'm sure it will cost a lot more to do things fully properly. The only other solution that I see, is to add a separate gain control to the subamp (you could place this in line from the headunit to the rear subamp and mount a pot somewhere in reach of the front console) That approach would probably work very well, but some behind the dash mods would be in order, etc. See what others suggest and weigh your options...
Good Luck!
Southbound
10-09-2002, 11:36 PM
#5
Instructor
Thread Starter
Join Date: Aug 2002
Posts: 154
Likes: 0
Received 0 Likes
on
0 Posts
NSXNEXT - Thanks, I plan to dynamat the doors and possibly the trunk (although I want the trunk lid to stay up when open - I'll have to check on that).
Southy - wow, you outdid yourself! I had to read that post twice to make sure I understood it Xtant does offer a remote gain control for the amp, and I'm thinking seriously about getting one installed. My fear is that if I turn up the gain too much I will get distorted bass, or worse, drive the amp into clipping.
We'll see the results with more dynamat and adjustable bass gain, before I consider a beefier amp.
Southy - wow, you outdid yourself! I had to read that post twice to make sure I understood it
Xtant does offer a remote gain control for the amp, and I'm thinking seriously about getting one installed. My fear is that if I turn up the gain too much I will get distorted bass, or worse, drive the amp into clipping.We'll see the results with more dynamat and adjustable bass gain, before I consider a beefier amp.
10-10-2002, 01:36 AM
#6
Pro
Join Date: Feb 2002
Posts: 698
Likes: 0
Received 0 Likes
on
0 Posts
egilsrud,
I'd definitely try the remote gain control for the subamp. If you are happy with the sound at speeds under 60mph... then you shouldn't need that much boost. If you have to drive the new amp into clipping to get the bass that you want... just think how horrible the bass would be sounding from the stock bose amp and sub! any way you go HAS to be an improvement over stock. If you damp the trunk with some lightweight material and add a little bit of extra gain for speeds at 80mph... you should be golden. This would be the BEST way to tackle the problem. Leave the door speakers alone so that you don't lose any punch out of them, and just add some extra level to the subamp when needed at highway speeds. If you can do this remotely... that would be sweet!
Good luck!
Southbound
I'd definitely try the remote gain control for the subamp. If you are happy with the sound at speeds under 60mph... then you shouldn't need that much boost. If you have to drive the new amp into clipping to get the bass that you want... just think how horrible the bass would be sounding from the stock bose amp and sub! any way you go HAS to be an improvement over stock. If you damp the trunk with some lightweight material and add a little bit of extra gain for speeds at 80mph... you should be golden. This would be the BEST way to tackle the problem. Leave the door speakers alone so that you don't lose any punch out of them, and just add some extra level to the subamp when needed at highway speeds. If you can do this remotely... that would be sweet!
Good luck!
Southbound
10-27-2002, 08:20 PM
#7
Racer
Join Date: Mar 2002
Location: Bronx, NY
Age: 45
Posts: 297
Likes: 0
Received 0 Likes
on
0 Posts
Originally posted by TopGum
?I would definitely suggest Dynamatting the entire trunk, rear deck, underneath the back seat and all 4 doors. That should keep a lot of road noise out."
Just wondering, how much does Dynamat weigh? It seems like this would add significant weight. A unavoidable trade off?
?I would definitely suggest Dynamatting the entire trunk, rear deck, underneath the back seat and all 4 doors. That should keep a lot of road noise out."
Just wondering, how much does Dynamat weigh? It seems like this would add significant weight. A unavoidable trade off?
Trending Topics
10-31-2002, 10:18 PM
#9
Instructor
Join Date: Oct 2001
Age: 57
Posts: 143
Likes: 0
Received 0 Likes
on
0 Posts
Got my Polk DX6's put in today, sound is good, a little under-powered I would say, from the stock HU
.... but still loud enough for me
TopGum, your money is on the way, you want any special delivery or 2-3 day Express OK?
Phil
11-04-2002, 01:17 PM
#12
Instructor
Join Date: Oct 2001
Age: 57
Posts: 143
Likes: 0
Received 0 Likes
on
0 Posts
I did the mods but discovered my driver's front tweeter is lacking- or NOT working...
NO highs from it, but the rest sound SO crisp ... SWEET
I called my installer and he will pull it out again when I get time, check it, i may have to just go without the cap on that door ???
I must have fried it or have a bad solder ? Any ideas ?
NO highs from it, but the rest sound SO crisp ... SWEET
I called my installer and he will pull it out again when I get time, check it, i may have to just go without the cap on that door ???
I must have fried it or have a bad solder ? Any ideas ?
11-04-2002, 11:20 PM
#14
Instructor
Thread Starter
Join Date: Aug 2002
Posts: 154
Likes: 0
Received 0 Likes
on
0 Posts
Originally posted by BlackBeauty
I did the mods but discovered my driver's front tweeter is lacking- or NOT working...
NO highs from it, but the rest sound SO crisp ... SWEET
I called my installer and he will pull it out again when I get time, check it, i may have to just go without the cap on that door ???
I must have fried it or have a bad solder ? Any ideas ?
I did the mods but discovered my driver's front tweeter is lacking- or NOT working...
NO highs from it, but the rest sound SO crisp ... SWEET
I called my installer and he will pull it out again when I get time, check it, i may have to just go without the cap on that door ???
I must have fried it or have a bad solder ? Any ideas ?
Sorry to hear of the troubles with your driver's tweeter. Here are some things to check:
1) Make sure ALL leads from resistors and capacitors are insulated properly - can't stress this enough!
2) Check your tweeter wiring. You should have disconnected (unsoldered) the tweeter wire from the positive speaker terminal. Then the 3.9 ohm/5 W resistor should be soldered to the tweeter wire, with the other lead of the resistor soldered to the positive speaker terminal.
3) One lead of the 4.7 uF/50 W non-polarized electrolytic capacitor should be soldered to the connection of the positive tweeter wire and 3.9 ohm resistor. The other lead should be soldered to the negative speaker terminal.
4) The terminator mod should be soldered to the negative and positive speaker terminals.
5) Make sure that the bottom of the cutout in the door frame for the speaker is well insulated! I would suggest 3 layers of duct tape.
If all of this seems to be OK, I would suggest removing the mods and reconnecting the positive tweeter wire to the positive speaker terminal. Then, reinstall and see if the tweeter works. If it doesn't, then the problem is indeed in the DX6 (and I sure hope it isn't).
Good luck, and let us know how it turns out.
11-06-2002, 08:00 AM
#18
Instructor
Join Date: Oct 2001
Age: 57
Posts: 143
Likes: 0
Received 0 Likes
on
0 Posts
Pics of my door ? I wouldn't do that to you ... I will take pics of my 12" Comp VR sub and amp with remote amp gain -- if you like
Polks are in the doors, can't see em -- But You sure can here em
Polks are in the doors, can't see em -- But You sure can here em
Thread
Thread Starter
Forum
Replies
Last Post
