Hi all,

I finally couldn't stand all of Iggy's ambition and finally mounted my second set of POLK DX6s in my rear doors. I still have EVERYTHING else stock. I found that with FOUR POLK DX6s, that my overall sound was too bright. I was afraid of that with the damn EQ in circuit. I do find it much cleaner though. I did some listening with just one rear speaker replaced and the head unit faded all the way to the rear... Then I would adjust the balance all the way to one side or the other just to hear the individual speakers. I wanted to try and see just how bright things might sound before doing the other rear. I was concerned that I might be better off to leave the stock BLOWS until someday when I bypass the EQ and add an amp to drive them right. HOWEVER, in my listening, I found that the BOSE JUST BLOWS! While the POLK might have sounded too bright, in comparison, the BOSE just kept distorting at decent volumes... especially with the bass notes. There aren't any high notes to speak of with the BOSE, so all I heard was mush up there. I decided that THE BOSE HAD TO GO! I just couldn't live with the overall distortion. Plus, ONE LOOK at them, and you just have to rip them out if you have any kind of pride :yack:

Today, I spent all day doing a POLK DX-6 mod... One of the many reasons that I bought them, was the fact that their tweeter wires and crossover cap are conveniently wired to a terminal strip on the back of the speaker. This makes it REAL easy to change the crossover cap to change the crossover frequency or to add a power resistor in series with the tweeter to cut its level and overall brightness down. I fooled around with a variety of 5Watt power resistors in series with the REAR door POLK DX-6 tweeters. I bought a bunch of resistors to sample, 2.7ohm, 4.7ohm, 6.8ohm, 8.2ohm, 10ohm. I settled on the 4.7ohm 5Watt resistor in series with the tweeter. A 5Watt resistor is sufficient with the STOCK Headunit/amp. I drove around with it cranked to the max for an hour straight, and only found the resistor to become ever so slightly warm. You had to use your little finger to feel the warmth. If music were a continuous sine wave, I'm sure the resistor would have heated up a lot more. But there's really only spurious peaks of sound over 3khz that the tweeter actually sees. So it's not really continuous power that we have to worry about. In an aftermarket amp, though, I'd definitely want to re-evalute this wattage and probably find that it would need to be moved up to a 10Watt resistor, depending upon its power output. BUT in the STOCK system, a 5watt resistor didn't even get noticeable warm with the volume cranked at 25 clicks for over an hour. IRONICALLY, with the tweeter totally disconnected, the speaker sounded very much like the BOSE response, only it could handle the bass! The POLKS are about 3db less efficient, so I've found that I needed to crank the level up higher with all four installed. What surprised me though was that I COULD TURN THE VOLUME UP ALL THE WAY TO THE TOP (30 CLICKS)AND THE POLKS STILL DO NOT DISTORT! In the old BOSE system, if I went above 25 clicks of volume there was obvious distortion. BUT, it appears that it was the speakers distorting as opposed to the amplifier distorting. With the four POLKS and the volume up ALL the way, I CANNOT make the amp clip or distort beyond a small acceptable amount(considering the overall quality of the head unit itself). I was driving around tonight and found myself saying that things weren't loud enough with the POLKS, then I tried to sing/yell to the music, and realized that I couldn't hear my own voice. That is usually my SPL calibrator. Point being, I think I had the POLKS putting out as much SPL as the old BLOWS, but the ears/brain were liking the clarity so much more, that it didn't seem as loud. LESS DISTORTION ALWAYS sounds softer and lets you turn it up louder before it actually sounds loud...

The mod is a piece of cake to do with the POLK DX6s. Like I say, it was partly why I chose them, because I knew I'd probably have to tweak with the brightness or else go through the hassle to remove the EQ. Somebody awile back who also put a pair of these speakers into their STOCK system was asking me if it were possible to do this sort of thing to bring down the brightness. (I apologize for not recalling which fine member of this board it was, but now I have some good news for you) I always knew it could be done, but wasn't sure of the values, or results, etc. so I didn't endorse it at that point. I can only open up so many cans of worms at once... But now, I've got some data and results to post. Realizing that going the route of bypassing the EQ and adding an additional amp is the RIGHT way to do things, this mod does still serve to produce another level of improvement with the STOCK system. It does so with a minimum of expense and invasive procedures.
The POLK DX-6s fit into the rear door just as easy or easier than the front doors. The door panels are REALLY simple to take off. Just ONE electrical connector to deal with. I used a single sheet of dynamat underneath each of my four speakers and it seems to help keep things smoother and tighter. It's not as nice as IGGY's cascade work, but for a simple mod, I think it's worth it.

As far as the actual speaker mod... Just unsolder the tweeter lead at the terminal strip point where the crossover cap and tweeter lead are soldered. Put some sleeving on the 5Watt power resistor leads (I always use teflon sleeving because it can handle the heat of a soldering iron, but any piece of stripped wire insulation would work just fine also) Use some Silicone RTV sealant or equivalent to glue the resitor down to the side of the magnet. (like the way the crossover cap is glued down, only higher up on the side of the magnet.) This will keep it from vibrating and rattling against the case, etc. It also strain relieves the solder connections and terminals. I put a band of "tie-wraps" around the magnet to hold it tightly in place while the RTV dried. Once its solidly glued to the side of the magnet just above the terminal strip. You can solder one of the leads to the terminal lug where the old tweeter wire was soldered, and then solder the tweeter lead to the other side of the resistor. IT'S THAT SIMPLE AND WORKS GREAT! Like I say, I ended up choosing the 4.7ohm/5Watt resistor. The power resistors in this size will be those retangular wirewound type that are about 3/8inch square by 1 inch long. This size fits just perfect above the terminal strip. A 10watt resistor would be about 2 inches long and might stick out to the side and cause door frame clearance issues. Although I'm sure they could be dealt with carefully. A 10watt or 20watt resistor would only be required for higher powered aftermarket amps... Also for anyone who has been hearing me rant about NOT using wirewound resistors in my "terminator" mod... THIS IS A DIFFERENT APPLICATION... This is used to pass actual audio frequencies. Therefore, in this case, we don't care about the inductive properties of a wirewound resistor. In this case we ARE ONLY dealing with audio frequencies and NOT RF frequencies. So a wirewound power resistor is just fine for this purpose.

For anyone out there who has done the POLK DX-6 replacement and is considering doing the rears or feels that the fronts are just too bright. Try this mod. Buy various values of resistors between like 2.7ohms and 8.2ohms and take the speaker out of the door. Make up some kind of extension so that you can put the speaker in your lap. Unsolder the ONE tweeter lead and use some clip leads to connect the resistors in series with this lead. You will be able to INSTANTLY hear the effect. This is the kind of A-B test where you will want to do things instantly and listen for an instant reponse... Unlike the "terminator" mod where your brain needs more time to take in the subtle changes. Although once you have selected a value that seems to cut the brightness down about right for you, you might want to give it a more serious listening test using various music selections, etc. You'll be interested to hear the speaker without the tweeter at all... just for grins. Then put various values of these resistors in line with the tweeter and decide what level of brighness you like best. Everybody's ear is going to be different in this respect. I found that 4.7ohm cut the tweeter output down by about 6db. I couldn't really hear much differnce to make it worth doing with a 2.7ohm resistor (3db). Once I went above the 4.7ohm value, the overall sound became softer yet, with more midrange prominence, but the OVERALL SPL also dropped. I found that the 4.7ohm value was a good compromise. I didn't want to cut it down TOOOO much, in case I bypass the EQ someday. Also the HIGHER the value of resistor, the MORE HEAT it will dissipate. If you choose something much more above 4.7ohms, install it temporarily and crank it for an hour and see how warm things get. If the resistor gets too hot to touch, then you will want to either lower the ohm value or increase the wattage, which will mean a harder mounting clearance and glue down process. Again, for me, the 4.7ohm just seemed about right, ALL things considered. This let me keep the treble control parked around 1 click down, and the bass control 1 click up. I CAN NOW CRANK THE VOLUME CONTROL FULLY OPEN AND NOT HEAR ANY SUBSTANTIAL DISTORTION... I'm not saying it's audiophile wonder system, but again, IT'S WELL WORTH DOING AS OPPOSED TO JUST LIVING WITH THE BOSE.

WITH A LITTLE MOD, FOUR POLKS ARE BETTER THAN TWO! You can custom tailor the brightness with a combination of tweeter resistors and the headunit treble control. It's beginning to almost sound sweet! In any case, I found that pitching the BOSE is a GOOD THING!

Good luck!
Southbound

 

hey southbound,

i just want to put in two of the DX-6's in my front. I have a 2002 TL-P and am i total newbie with doing any mods to my car. if i find the speakers, do you think i could do this with a few tools? or should i take it to a professional

thanks

 

Taestee,
The polk install is pretty darn easy. If you know lefty loosy righty tighty then I would do it yourself.

Read this thread:Polk info , I gotta warn you though, be prepared to do some serious reading because it is ONE LOOOONG THREAD. After you are done you will have intimate knowledge of the subject at hand.

Cheers,
Iggy

 

Southbound,

Once again, great research, and thanks for sharing it with the rest of the forum to benefit from. As one who has taken your advice and done the front DX6 upgrade I too have been considering the back, but didn't due more to the midrange notch than the brightness.

A couple of questions however: When you pad the tweeter with a resistor like that don't you introduce phase shift and other audio anomalies? Aren't you also changing the load (resistance) the speaker sees? It's been a few years since my audiophile days, but seems like I remember something about that when studying crossovers. Of course this may not matter in a car system where your soundstage is severely compromised anyway, and let's face it, these electronics are not exactly audiophile-clean. Also, with all of the "satellites" now down 3db you could say alternatively that you just moved the subwoofer up 3db. That might not be a bad thing, your thoughts?

 

Hey Southbound,
Thanks for all the good info.
I have a quickie. I am getting another pair of DX6 for my rear doors and I plan to disconnect the tweeter from the rear speakers since I don't want them to be to bright. Will it change the impendence of the speakers if I disconnect the tweeter ?

Thanks dude.

 

RandyL, dr...
You just raised very valid questions. However, I think your quote above just answered your own question. Although, In this "simple" crossover of just a series cap with the tweeter, there should be minimal phase shift. The series crossover cap shifts the phase one direction, and the inductance of the tweeter coil moves it back the other direction to center. Since a resistor by itself doesn't shift any phase, if your initial signal is in phase, then the resulting signal would still remain in phase. There would be slight impedance bumps througout the frequency range, especially near the crossover point(even with the stock speaker) but as you say, this isn't exactly an audiophile environment, and NO speaker is without impedance bumps. IN ANY crossover network that I've seen, they always use a resistor or an "L-Pad pot" to lower the tweeter gain. I'm sure that the more elaborate car audio crossover networks that have a switch or jumper to change the tweeter output + or - 3db, are simply adding or shorting out a series resistor. So play with what value sounds best for you, and don't worry about a phase problem. It would be so minimal as compared to the attentuation results. It would never come close to nulling anything out, or causing an actual reverb delay, etc.

As far as completely disconnecting the tweeter. YES, that would change the overall impedance of the total speaker. (So would adding the series tweeter resistor). However, it would only shift the impedance up by 4ohms at the most. This would have no detrimental effects that I can think of. All it would do would be to let the amp run cooler by driving a higher impedance load. I wouldn't want to lower the impedance for fear of overworking the amp, but to raise it up to 8ohms would only let the amp cruise. I guess if you put a resistor in series with the woofer, it might adversely affect the damping factor. The bass response might become a bit more sloppy. But damping factor isn't that significant up at the higher tweeter frequencies, since there is no REAL physical movement or "MASS" of the cone to stop and start abruptly.

Therefore, all things considered, I believe that either of these options are definitely superior to living with the BOSE. I think you'll find that you might not want to take the tweeter completely out of circuit, but then each of us desire different results. With my 4.7ohm/5Watt resistor mod to the rear tweeter, and the fact that the POLKS are about 3db less efficient, I have noticed that the sound stage has moved more forward in the car after the mod. Then again, it may have moved more to the rear after just replacing the front BOSE with the less efficient POLKS while leaving the louder rear BOSE in place for a month. I can't remember how it used to sound completely stock now? I did sit and listen in all five positions in the car yesterday. I found that sitting in the middle of the back seat and moving my head up between the two front seats was where the "sweet spot" was. Too far back, and all I got was the subwoofer and not enough brightness from the front. Too far forward and the rear fill seemed to be lacking from what I was used to with the BOSE. However, It's a LOT cleaner. I have played around with moving the fader a click or so to the rear to help bring a little more depth back to the soundstage. NOTHING is perfect. Especially with this compromised system and solution. BUT, it's definitely significantly better than the stock distorted and mushy Lo-Fi BOSE system.

It's important to note the difference between turning the treble control down and cutting the overall tweeter level down. Turning the treble down will start to "roll off" high frequencies at some break point. From that point upward, the frequencies will be more and more attenuated. The roll off may be 6db, 12db, or even 18db per octave or more depending upon how many "reactive poles" are involved. With the treble control, if you turn it down to drop 6db at 5Khz, you will be down another TWO octaves or another extra 12db, 24db, or even 36db at 20Khz. However, when putting a series resistor into the tweeter circuit, you are "cutting" ALL of the frequencies equally. So, if you put a resistor in series with the tweeter to drop it down by 6db at 5Khz, it will still only be down by 6db at 20Khz. So it's important to realize the difference between these two types of response controls. A combination of both is really needed to provide the infinite adjustments and optimum results. This is what a professional 1/3 octave graphic equalizer would allow you to achieve through "selective" attentuation. (or accentuation). Sadly, I don't think you're going to find that caliber of equipment in a car audio stereo, Especially this Acura Bose system! A single treble control just can't provide this type of selective response adjustment. All it can do is start somewhere, and just keep rolling off, at who knows what rate? I guess it could have a shelving frequency built in where it quits attenuating any further... but who knows where and how much???

In our case of just trying to get the best results out of simply replacing the speakers alone... All we can do is give ourselves the best combination of adjustments possible without replacing the entire system. It's definitely a compromise solution at best... but still worth the minimal expense and effort involved.

Hope some of this helped you to clear up your questions...
GOOD LUCK!
Southbound

 

Hey Southbound I'm glad to see that you've put in those rears!!! Now I wonder how that AC/DC sounds I've finally finshed my set-up as well and thank you for all your help! Maybe next week sometime you could take a listen but then you'll want to get rid of that stock eq in a hurry! so I don't know if that's such a good thing!!! Anyway congrats and thanks! Brad

 

Hey SB -

You got me thinking - again.

What about using resistors on all 4 tweeters. Maybe 2.7 ohms (or 3.5 ).

That way the sound would be more even front to back and the rear passengers wouldn't get such a raw deal.:yack:

 

heyrandy,
If you're not planning to ever bypass the factory EQ, you have probably come up with a GOOD idea.

I found the resistor mod to be very easy to do. The factory HU doesn't put out enough power to even warm up a 5watt power resistor at tweeter frequencies, and it can easily be soldered to the POLK DX6 terminal strip and then glued with RTV to the bottom edge of the magnet. If you go for it, go ahead and unsolder the crossover cap on the positive "side terminal" and CUT THAT SIDE TERMINAL OFF! Then resolder the crossover cap back to the center of the terminal where the rivet is. This will ensure that you don't end up with a potential short again... I think it's that speaker "side terminal" that ends up rubbing/cutting against the door hole cutout.

Be prepared for a lot of trial and error to come up with the values that suit your particular ears. I didn't find the 2.7ohm value to make enough difference to warrant the extra work, etc. I found that the 4.7ohm cut things down about right, while still leaving PLENTY of high frequency response. Common 10% resistor values would be 2.7ohm, 3.3ohm, 3.9ohm, 4.7ohm, 5.6ohm, 6.8ohm, 8.2ohm and 10ohm. Those would be values that you could expect to find in an electronics supply store. FRYS electronics actually had a great selection of all of these values.

If you feel inclined to go through the mod process, let us all know what values seemed right for you. If you're handy with a soldering iron and desoldering techniques, it really is a piece of cake mod to try. Again, it's half of the reason I selected these speakers in the first place. Just remember, if you go too far, and then bypass the EQ someday, You may have to go back in and remove the resistors. How many times can we take these door panels on and off before we screw something up?

Anyway, GOOD POTENTIAL IDEA!

Also, thanks for the great informative petroleum/gasoline report! You definitely know your stuff in that area. I too need to back off of the board for awhile to get caught up on work and family life. But I felt I owed you a response and a THANK YOU for your reply. I have both Chevron and Unocal cards... I guess I'll just keep putting those two fuel companies gas into my TLS. So far I haven't had any pinging with the 91 Octane Premium, But I wish we had higer octane out here. I wonder why they dropped the 92 octane?

Take care,
Southbound

 

Southbound -

Quote: How many times can we take these door panels on and off before we screw something up?

My thoughts exactly! That's why I want to do things right the first time. I never plan to upgrade my amp but will upgrade the back doors with another pair of DX6s. I also plan to add your resistor/cap mod at the same time and only want to do it all one time (tough customer!).

Anyway, it doesn't have to be perfect, but what would your best guess be on the right resistance if I did all 4 speakers?

You think it sounds good with the fronts unmodified but with the back tweeters having an extra 4.7 ohms. So would 2.35 ohms all around give the same effect if your ears were equidistant from all speakers? I'm sure it's not linear and since your ears are closer to the fronts, I'm guessing it should be lower than 2.35 (do they make lower value resistors - say 2.0?).

Any advice would be greatly appreciated.

About octane values decreasing to 91, without MTBE it gets much harder to make the higher grades. MTBE has a blending octane value of something like 110 and ethanol is significantly lower (I'll look it up tomorrow at work). The only other way refiners can make high octane (without costing a buttload) is with tetra-ethyl-lead, MMT, and aromatics (benzene, toluene and xylene). And of course these components are restricted - especially in CA.

Did all of the refiners change octane grades or only some? I'll call my contacts and ask them why they changed if you want.

Our cars have a knock sensor so they should never knock - even using 87 (or 85 in high altitudes). 94 octane that is sold out east is mostly a marketing game. Very, very few cars can make use of the incremental octane. If you are going for 1/4 mile times at the local drag strip and have added the common mods and reduced all unnecessary weight like seats, spare tires, soundproofing, and speakers, you may notice a slight difference with grades above 91. But, if this is your daily cruiser, save some money and stick with 91.

 

heyrandy,
It's probably hard to give a value that would be accepted by everyone. When I put the speakers in my rear, I hooked the new POLK up with insulated clip leads and various values of resistors. I had the speaker lying in my lap so that I could hear the tweeter pointed straight at me. I wasn't really listening to the overall response this way. Obviously the bass was lacking out in the open air, but I could tell how much the tweeter "BITE" was cut down. I found that I could just BARELY detect any change when I shorted in and out a 2.7ohm resistor in series with the tweeter.

It took upwards of 4.7ohms before I felt a significant drop in the tweeter harshness. BUT, this was with the tweeter IN MY FACE... Once I installed it back in the door, I found that the grill cloth cut down some more of the brightness. Also, in hindsight, The rear speakers come off way less bright because the high frequencies are very directional. To hear the highs from the rear speakers, they have to come through the back of the front seats first. Therefore, things would probably sound better if I had done things in reverse. If I cut down the brightness of the front speakers and left the rears stock, things might sound more balanced???

I don't want to keep taking my panels off and on either. Each time, the weather seals will fit looser and the snaps will fit looser, etc. Not to mention that I'll get in a frenzy sometime and run a screwdriver though something or drop the panel on the concrete and scrape it up, or break an electrical connector, etc. HOWEVER, the rear door panels are easier to do. There is only one connector to deal with... everything else is the same.

If I had to guess at a value, it would depend upon how bright you perceive the stock POLKS with the STOCK system to sound... If you think things are waaaay too bright now, I'd probably go with 4.7ohms all the way around. The overall volume will be a bit less, though, especially with all four speakers replaced. I have found, though, that turning up the head unit all the way still does not really distort the POLKS... SO you can get away with turning the volume knob up a few more clicks than you could with the Bose. If you think the POLKS are just a BIT bright, and you can now live with the treble control somewhere near middle, then I'd go with 3.3ohm or 3.9ohm/5watt resistors.

I'd buy all three of these values and do a quick clip lead in your lap test like I did. It will give you an idea of what you're going to end up with. Keep in mind that things will be toned down a bit from the speaker grill cloth and the fact that your head won't be on the floor... BUT, I don't think any value down in the 2ohm range would make enough difference to be worth the effort. Like I said in hindsight, I'd probably let the rears have more highs than the front, unless you're concerned about the rear passengers sound... BUT just in case there is a bit of a phase shift involved with this mod, it would probably be best to keep them ALL the same value. I'd go with 3.9ohms all the way around, but give yourself some playtime with the other two values... just to make yourself feel comfortable with that decision.

I take it you're handy with a soldering iron? If so, the RC terminator mod and adding the tweeter resistor is really easy to do. Like I've also said before, while you're at it, unsolder the crossover cap from that side terminal that shorted you out... then cut it off! Then resolder the cap to the center of the terminal. Glue down the 5watt resistor to the bottom edge of the magnet and use some insulation on the leads. I use teflon insulation because I happen to have it and it won't melt with a soldering iron... But just strip some insulation off of a piece of wire and slip it over the resistor leads and you should be fine. I also used a band of two tie wraps to hold the resistor tight against the magnet as the RTV dried overnight. In fact, I left the tie wraps on in the final install. The last thing I want, is to have the resistor break loose from the RTV and then rattle/buzz against the magnet during bass notes, etc. The magnet will also heat sink the resistor, even though I drove around with the tweeter resistor installed and the level cranked to 25 clicks for one hour and could just BARELY detect some warmth from a 5watt resistor in the STOCK system with the resistor hanging in the open on the floor.

Hope this helps? Good luck. Oh yeah, if you haven't already done it... put a sheet of dynamat under each speaker spacer. I think it really helped to tighten up the bass as compared to my tests without it. Again, you want to do all you can the first time with respect to these door speakers installed with the stock system. They need all the help they can get.

Thanks for the octane tips!!! YES, all of the stations out here have now dropped to 91 octane premium. Unocal was first, then Chevron followed months later... Glad to hear that you think it should be sufficient. SO with respect to the bottom line about our gasoline out here in California, would you say that it is better or worse than other states gas with respect to keeping our injectors and intake valves clean, etc.? I know it's probably the best for the air quality... but how about the car itself???

Thanks and GOOD LUCK! I'll be interested to hear how things work out for you... I may have to go back in JUST ONE MORE TIME... depending upon your reports. By the way, Do you already have a second pair of the POLK DX-6s? If not, I'm afraid you may not be able to find anymore out there at this time

Southbound

 

Sorry if this question is a repeat. I just want to clean up my sound a little and add some highs. If I just add the POLK DX6s to the front as they are, will the sound be too bright? I don't want to hassle with everything else. Thanks in advance.

 

Walker -

I currently have only changed out the fronts with the Polk's. I typically have my treble set in the middle or maybe down 1 click and the bass up 2 clicks.

Of course it is brighter than stock but that was my main reason for the mods. The Blows are a real POS when you take a look at them. The Polk's weigh almost twice as much.

It is not overly bright except for some radio broadcasts (they probably boost treble?). Most of my CDs and tapes sound pretty good without turning down the treble from center. I wouldn't add resistors if just changing out the fronts.

Be sure to remove most of the rain shields. Before I did so I had to favor the fronts by 2 clicks on the fader since the Polk's were sounding quieter. Now it's centered after trimming the shield to the gasket.

Good luck!


SB -

Both MTBE and Ethanol have blending octanes around 110 (+/- 3) but Ethanol adds ~1 psi to the vapor pressure of the gasoline so the refiner has to make a "heavier" blend stock (ie, lower vapor pressure) so overall gasoline volume is decreased.

I talked with a contact at Chevron today and he said that they lowered the octane from 92 to 91 for a couple of reasons with the MTBE phaseout being the biggest since it's hard to boost octane in CA these days. Basically they can make more volume of premium at 91 than 92 (and of course premium typically has higher margins). He said that they haven't heard many complaints and no major automakers are asking for anything higher than 91 anyway.

I believe that you probably have the "cleanest" gas in the world in CA (except for that dam EtOH) so I wouldn't sweat which brand you bought.

As a side note, my Acura dealer sells Chevron fuel injector cleaner at the parts counter so that's another vote for their additives. But again, I haven't heard of very many people having injector troubles these days. I recall that the Bosch injectors in BMW's were having trouble with certain gasoline additive packages back in the mid to late 80's. But of course those additives were made to clean carbs. The automakers and oil companies have learned a few things since then.

 

Thanks Heyrandy

 

SB

When you put the Dynamat on, do you cover the white plastic or cut it out?

Also, when my door speakers didn't work for a couple of weeks and I only had the sub to listen to, it didn't seem like the electronics cut the highs out to the sub very well (at least not compared to my home system). I could still listen to the radio but of course the sound sucked.

It was almost like Blose decided that if they could make 6.5 inchers sound like tweeters, why not do the same for the 9 incher?

Anyway, because of this, I'm wondering if I should include a capacitor in the blackum box setup for the sub or does it make any difference due to the low voltages?

Thanks

 

heyrandy,
I bought the dynamat extreme. I figured that I should get the best stuff and do it right from the beginning. It cost like $19.99 for a pack of two sheets. So two packs does the four speakers. I pulled the white plastic spacer off and attached the dynamat directly to the door frame covering the speaker door hole cutout. Then I took the utility knife and cutout the center section of the dynamat where the speaker will mount through. I located the screw holes and then poked holes through the dynamat with a small screwdriver or icepick. I had to also use some scissors and cut off a little bit of some of the dynamat corners. Otherwise the sheet would hit on the armrest etc. Just center it around the speaker hole the best you can. It seemed to stick very well. Just rub it into all of the door frame contours really well. ALSO, THE EXTREME DYNAMAT IS COVERED WITH FOIL! The foil will conduct... So cut it back just a bit like 1/4 inch at the bottom of the door hole cutout so the speaker terminals cant short to the foil. You don't want to go down that road again. The foil can be cut back and peeled away fromt the actual dynamat. Then mount the white plastic spacer back over the top of the dynamat with the screws going all the way through everything. The dyanamat is only like 1/16 inch thick and is plyable, so it doesn't cause any depth issues.

IN THE TLS, the bass voltages are so low, due to the 1/2ohm woofer, that I found the 100ohm resistor to be just fine without adding a cap. I did a zillion listening tests with heavy bass material and the fader set to the rear, and it might have been my mind, but it seemed like things just kept sounding a bit smoother with the capacitor out of circuit. I put a .1uF in series and it was hard to tell if it made much difference between the .05uF? It think it was a bit better, but I kept going back to the resistor by itself and kept finding it to sound smoother. SO THEN I DROVE AROUND WITH THE 100OHM/1WATT RESISTOR CONNECTED AND CRANKED HEAVY BASS MUSIC FOR AN HOUR AND KEPT PULLING OVER AND CHECKING THE HEAT ON THE RESISTOR. IT JUST BARELY GOT WARM TO THE TOUCH WITH THE LITTLE FINGER. I decided to up the wattage to a 100ohm 2watt resistor and gotta figure things are fine. (WITH THE STOCK SYSTEM!) IN YOUR HOME SUBWOOFER SYSTEM, I would definitely put a .1uf/1kv cap in series with the 100ohm/2watt resistor to be safe. 1watt resistors should be fine for all applications, but I have put 2watt resistors in my home systems where space is not an issue. Just don't jump up to 5watts where the resistors become wirewound types.

NTE does make all of this stuff, both 1watt and 2watt flameproof resistors. They should also carry a variety of the 5watt tweeter resistors. I know that NTE makes everything... as to what the local store stocks, may be a differenct story? Yeah, it sounds like you need a shopping list and then go for it.

Good luck! I think you'll be glad you did.
Southbound

 

hr,
In case I didn't make myself clear, You want the dynamat to cover all the way up to the edge of the door hole cutout. Just peel back 1/4inch of the foil from the top of the dynamat down at the bottom of the door hole cutout. (for short circuit protection) Poke holes through the dynamat where the screws will go and mount the white plastic spacer ON TOP of the dynamat. That is probably the most important thing to do to make sure that the speaker vibrations are damped from the metal door frame. You definitely want the spacer mounted on top of the dynamat or it won't do you much good. If the speaker and spacer were still mounted against the steel metal door, the metal door would still tend to resonate. The dynamat would still probably help stop some of it, but if the speaker and spacer are placed on top of the dynamat, a LOT of the resonances are damped out before they ever really vibrate against the metal door. TIGHTER SOUND, LESS BUZZES AND RATTLES!

SB

 

My speaker source found me another new pair of DX6s for $90 even. Picked them up at lunch.

I asked him about Dynamat and he said that he has something better. His source is a buddy that works at the Ford plant and can get me the stuff they use for soundproofing. He said that it is real sticky and has a foil liner also but it sounded slightly thicker than Dynamat?

Anyway, he made it sound like it wouldn't charge me much if anything. How much should I get? What size Dynamat pieces did you use?

Thanks

 

heyrandy,
I'm sure that there are probably several different and/or better materials to use than dynamat. I just used it because it was hanging there at FRYS electronics where I bought the speakers.

My hat goes off to "Iggy" for his intense and thorough application of his dampening material. If you saw his pictures of his door work you would be impressed by the way he covered every contour of the ENTIRE door panel. I just didn't feel inclined to go to his level of mod work with a torch and all. I used one sheet of dynamat under each speaker. The sheets are like 1 foot square. I also just realized that you were asking about whether or not I put the dynamat over or under the white plastic that covers the entire door, NOT the white plastic spacer. Duhhhhh. I was reluctant to dismantle any more of the stock car parts than absolutely neccessary. I didn't even want to drill new mounting holes into the door frame (hence the Polk DX6s again). I guess I'm a bit concerned about warranty issues, as well as screwing something up or creating new rattles, etc, etc. Therefore, I didn't remove the white plastic that covers the door panel. I found it to be very taut against the door frame at that area. I think it was glued down around the speaker area. If it was loose and flapping around, I'm sure I would have thought twice about just putting the dynamat on something that didnt' really adhere to the door frame. I can't quite remember everything now, but I do know that I didn't remove the white plastic weather door covering sheet. I also know that everything pressed down real nice and tight against the door frame over whatever white plastic sheeting was present there. The dynamat is kind of like sticky tar paper with foil over the outside of it. It pressed down and stuck real nice to every contour of the door frame. It wasn't like it was stuck to some flappy piece of sheet plastic. Plus the speaker spacer screwed down through it keeps it even tighter... So I think you'll find it the same way. It only takes a few more minutes to install and makes you feel a lot better about the installation.

As far as the sound improvement. All I can say is that I had a listening demo between another member of this forum. (BFOR3) We met up at the point where we had both changed out only the front speakers with the POLK DX6s and everything else was stock. We took the same CD back and forth between cars and played it at the same volume levels by counting the clicks of the volume control. At that point in time the only difference between our systems was that my speakers were mounted with one sheet of dynamat and I had also installed my terminator mod. I'm sure he would testify as well, but at that time, my system sounded significantly better. It's hard to know which mod did what because I installed them both at the same time. He kept commenting upon how much louder and tighter mine sounded, especially in the lower mid and bass regions. (probably dynamat related) We both noticed improved clarity and the fact that we could turn it up louder before it sounded blaring. (typcial terminator mod effect). He has since added an aftermarket amp and new subwoofer system. So I'm sure his system now blows mine away. (Congrats BFOR3!)But there was a point where the dynamat and terminator mod put my system noticeably ahead.

So use what you wish... I'm sure anything will help. Some materials are bound to be better than others. And more is probably better... I just went for what was easy for me to buy and install. The regular dynamat looked like it was more rubbery without any foil covering. It might produce a rubber smell??? The dynamat extreme was only $5bucks more per pack, so I popped for it. I don't notice any smell from the amount that I have used in the door panels. It would be nice to have the entire INSIDE of the door panels coated with something... but then it's only a car I guess... Again, I only used one sheet per speaker (about one square foot)

BTW, I fueled up at the local Unocal station tonight and the pump said that the product contained MTBE? (known by the State of California to be harmful to the environment)Do you think that it is just left over labeling from the days when it did have MTBE? OR could we still have that out here. If so, should I choose gas that does contain it over gas that doesn't say it contains it?

Thanks again!
SB

 

Unocal doesn't have any refineries anymore. The one in Wilmington was bought by Tosco which was bought by Phillips who just merged with Conoco. But last I heard, the refinery was using the "76" marketing brand logo, etc. The last time I was there they still had the butane sphere in front painted orange with the 76 logo on it?

Anyway, I know they (the refinery) made the switch to EtOH from MTBE but it caused them lots of grief with the higher vapor pressure. So they had to buy lots of alkylate to be able to make CA-spec gasoline.

Maybe the stickers are leftovers, maybe the refinery stepped back and uses MTBE again, or maybe the gas station gets their gas from somewhere else??? I'll try to find out for you.

I a nutshell, I prefer MTBE over EtOH in an engine since MTBE is more like oil (more lubricity) and doesn't carry water with it or dry out rubber parts etc.

But I like EtOH since it is better for the alkylation business. MTBE is of course worse when the filling station's storage tanks leak. And they are both stupid and ineffective in reducing smog in any car with a working O2 sensor.

 

heyrandy

Would you share your source for the DX-6s? I'm in the market for 2 pairs.

 

I was looking on ebay (search "polk dx6") and bid on a couple of pairs but was unsuccesful. Then I looked at the past autions (completed items) and saw that a guy from KC was trying to sell a pair but his reserve wasn't met so no sale.

Anyway, I emailed him and we hooked up for $90/pair cash a couple of months ago. When I emailed him about another pair last week he didn't have any but found a NIB pair a couple of days later.

Since you live in CO, I would probably go the Ebay route rather than the guy I used. You can probably get a new pair for $90 plus $10 shipping or a used/demo pair for half that. At least with ebay, you have some recourse if the goods aren't what is claimed. Plus you can see the history of the seller and if he has any complaints on record.

By buying them locally, I was able to see that the speakers were still sealed in the factory bags so I figured that they were probably OK. I don't think that I have a guarantee (no receipt) except that the guy who sold them to me said he would get them serviced through his suppliers if I had any troubles???