Attentuate a car speaker

Squishman

Squishman

Audioholic General
Not an AV topic, but at least I chose the off-topic forum!
I have a question if someone who is a techno-wiz can help. I improved my dash speakers of my car stereo. and wow, it really sounds amazing. The dash speakers and door speakers are tied together as the fronts and the rear are the the rears. So, six speakers, plus a powered sub. It is a 2005 Grand Caravan if it matters. The new dash speakers are to replace the crappy Chrysler dash speakers. My problem is that now the left dash speaker is too loud and I do not want to use the balance control as a fix for obvious reasons. Can I add a resistor or something to the positive wire going to just that speaker? If so, I need to know everything like the value of the resistor to buy and if is there polarity involved in hooking it up, etc. Thanks!
 
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pewternhrata

Audioholic Chief
Where are your speakers placed? The best way to combat a louder speaker in cars is balance and fade (left right, front rear) how did you wire the speakers? (6 channel amp?) did you use any component speakers? (Mid and tweeter with x-over) Are you utilizing a center channel?
Sorry for the list of questions. If you could list what your equipment is I should be able to sort it out.
 
Squishman

Squishman

Audioholic General
4 channel amp. No. center speaker. Dash and doors are tied together as fronts. So I do not want to use the balance as I would lose the door sound. Plus, I would lose the left rear as well if I just turned the balance more to the right. So, nope. I need something to add to the line I believe. What that is, I do not know. Hopefully an expert will pipe in who understands my plight.
 
P

pewternhrata

Audioholic Chief
4 channel amp. No. center speaker. Dash and doors are tied together as fronts. So I do not want to use the balance as I would lose the door sound. Plus, I would lose the left rear as well if I just turned the balance more to the right. So, nope. I need something to add to the line I believe. What that is, I do not know. Hopefully an expert will pipe in who understands my plight.
What are your speakers in the door and what do you have on the dash? Assuming a mid in the door and high in the dash? Is the door or dash too loud?
 
Johnny2Bad

Johnny2Bad

Audioholic Chief
As long as it's only a tweeter or small full-range ( a low power device) you can add a power resistor to attenuate the one speaker. Get one rated for about 10 watts to be safe (5 is probably fine, but it's a spec that is cheap to go safe on),and maybe buy a set, 0.5 ohm, 1 ohm and a 2 ohm. That will allow you to try 0.5, 1, 1.5, 2, 2.5, 3 and 3.5ohms as the attenuation level, pretty much guaranteeing you will find something you like volume-wise.

You could just guess and buy only 1 resistor, but they are not terribly expensive and if you find you bought the wrong one, with shipping, you'll have spent too much.

You can choose either ceramic or aluminum-bodied. They eat power by transforming it to heat, leaving less to drive the speaker, so be careful where you place them so they have free air around them and there isn't anything likely to melt at the installation point. They can go anywhere in the speaker line to your offending speaker. You just have to install it in either your (+) or (-) line, doesn't matter. If you use more than one resistor, you could even install one in each line, at the same point, which might be most convenient. Or you can install them in series (one after the other) in just one line. All up to you.

Examples:
https://www.parts-express.com/1-ohm-10w-resistor-wire-wound-5-tolerance--016-1

https://www.parts-express.com/051-ohm-5w-resistor-wire-wound-5-tolerance--015-.51

Don't make changes to the speaker line or have loose connections during any testing, while the system is powered up. Turn everything off (maybe shut the car off totally), make a change, insure the connections are well insulated and secure, then turn the car/radio on and check the levels. Be sure to listen at a number of loudness levels, from quiet to loud (or as loud as you will ever listen, at freeway speeds).
 
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highfigh

highfigh

Seriously, I have no life.
Not an AV topic, but at least I chose the off-topic forum!
I have a question if someone who is a techno-wiz can help. I improved my dash speakers of my car stereo. and wow, it really sounds amazing. The dash speakers and door speakers are tied together as the fronts and the rear are the the rears. So, six speakers, plus a powered sub. It is a 2005 Grand Caravan if it matters. The new dash speakers are to replace the crappy Chrysler dash speakers. My problem is that now the left dash speaker is too loud and I do not want to use the balance control as a fix for obvious reasons. Can I add a resistor or something to the positive wire going to just that speaker? If so, I need to know everything like the value of the resistor to buy and if is there polarity involved in hooking it up, etc. Thanks!
Here's a link to a site that's geared for car stereo and alarm people, but the audio principles apply to any situation- the site name is https://www.the12volt.com/ and they have circuits for this application. You want to use an L-pad. A power resistor will work, but it will change the total impedance.

If you do use a power resistor, you'll need to determine the attenuation needed, then find the impedance of the speaker. FYI- not all car speakers are 4 Ohm and this is probably the reason your new speakers are more sensitive. With a dedicated amp, they can use whatever they want, as long as nothing in the system changes. Double the resistance and the level will drop by 3dB.
 
Squishman

Squishman

Audioholic General
Great info thx folks. The door is not too loud, just the left side dash. Door are 3 way 5" Alpines and the dash are 4" 3 way pioneers. The original dash speaks were just these lousy 2" full range cones in a 4" frame. I'll post results after I get the parts. Thx again.
 
Johnny2Bad

Johnny2Bad

Audioholic Chief
I never use L-pads for anything; a rheostat that can handle that much power sounds bad to my ears, and an L-pad runs the speaker out through two of them. And since there is no crossover network in his single speaker setup (where a change in resistance could alter the crossover parameters),it's not necessary to design for constant impedance.

No amplifier that belongs in any audio system should have a problem with moderate added resistance; in most conventional amplifier topologies, it actually increases stability. The effect: is power ouput falls, which is the goal.

Finally, L-Pads cost the most.
 
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highfigh

highfigh

Seriously, I have no life.
I never use L-pads for anything; a rheostat that can handle that much power sounds bad to my ears, and an L-pad runs the speaker out through two of them. And since there is no crossover network in his single speaker setup (where a change in resistance could alter the crossover parameters),it's not necessary to design for constant impedance.

No amplifier that belongs in any audio system should have a problem with moderate added resistance; in most conventional amplifier topologies, it actually increases stability. The effect: is power ouput falls, which is the goal.

Finally, L-Pads cost the most.
First, I never mentioned anything about rotary L-pads. A fixed L-Pad is two resistors that attenuate AND maintain the impedance- it's one resistor in series and another parallel, named because the diagram looks like an L. For that matter, it might be helpful to find the amplifier and wire the front speakers in series to drop the level by 3dB.

Ever listen to Revel speakers? They use L-Pads for their tweeters in some models. Apparently, their l-Pads sound better than most. Or, maybe L-Pads don't screw up the sound as much as you think- ever done a blind test for this?

Second, the OEM audio systems from Chrysler and others use speakers made for them with unusual impedance because A) they can and B) to prevent people making changes to "their" system without jumping through a few hoops. Two 4 Ohm speakers in parallel is 2 Ohms and not many car stereos like or survive that when cranked. Chrysler used 10 Ohm speaker loads for years before they started using systems "Designed by Mark Levinson". Put a 2 Ohm load on that amp and I bet it will be pretty unhappy.

Third, who said the amplifier in most OEM car stereos are "decent"? Better than they were, but still not what they could be. They ramped up the quality because they finally realized they were losing billions of dollars to the aftermarket (Thank you to the automakers for taking their time in that) but that doesn't mean they spend a lot of money for it.
 
Johnny2Bad

Johnny2Bad

Audioholic Chief
Many loudspeaker manufacturers use L-Pads, particularly in the HF driver section. But as you say, it's common to use switches, not rheostats. But if he were to search for L-Pads on Google, he wouldn't be finding that type. It's true (obviously) that you never mentioned anything about rotary L-Pads ... what you did was mention L-Pads without any indication of which type you meant.

Configuring an L-Pad without electronic experience isn't something I would normally recommend to someone who had to ask the question. It is in essence the design of a crossover, because constant-resistance networks are a common component of all but the simplest capacitor-limiting HF networks. No switch needed, but math is.

OEMs use low impedance amplifiers in order to generate high power from limited automotive 12V supplies. It was the standard practice of BOSE when they contracted to supply premium audio ... a BOSE system using that very technique was an option on my 1990 Miata, so it's far from a new idea, and it's been adopted industry-wide since.

I know of no Class A, AB, or D amplifier design that cannot handle a slight increase in impedance (resistance) at the power outs. In fact they can handle excessive additional resistance without issue.

There is no need to go through discovering the actual speaker impedance if you buy a small selection of Power Resistors and experiment to achieve the attenuation desired.

And it's still going to be more expensive to configure an L-Pad over a single power resistor.
 
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KEW

KEW

Audioholic Overlord
Great info thx folks. The door is not too loud, just the left side dash. Door are 3 way 5" Alpines and the dash are 4" 3 way pioneers. The original dash speaks were just these lousy 2" full range cones in a 4" frame. I'll post results after I get the parts. Thx again.
I have to ask if you can explain why the left side dash is too loud and the identical speaker located right side dash is not too loud!?
The dash speakers should be at the same level given identical speakers!
I could understand both dash speakers being out of balance from the door speakers since they likely have different efficiencies, but if the right dash speaker is a reasonable match for the door speakers, something seems wrong.
 
highfigh

highfigh

Seriously, I have no life.
Many loudspeaker manufacturers use L-Pads, particularly in the HF driver section. But as you say, it's common to use switches, not rheostats. But if he were to search for L-Pads on Google, he wouldn't be finding that type. It's true (obviously) that you never mentioned anything about rotary L-Pads ... what you did was mention L-Pads without any indication of which type you meant.

Configuring an L-Pad without electronic experience isn't something I would normally recommend to someone who had to ask the question. It is in essence the design of a crossover, because constant-resistance networks are a common component of all but the simplest capacitor-limiting HF networks. No switch needed, but math is.

OEMs use low impedance amplifiers in order to generate high power from limited automotive 12V supplies. It was the standard practice of BOSE when they contracted to supply premium audio ... a BOSE system using that very technique was an option on my 1990 Miata, so it's far from a new idea, and it's been adopted industry-wide since.

I know of no Class A, AB, or D amplifier design that cannot handle a slight increase in impedance (resistance) at the power outs. In fact they can handle excessive additional resistance without issue.

There is no need to go through discovering the actual speaker impedance if you buy a small selection of Power Resistors and experiment to achieve the attenuation desired.

And it's still going to be more expensive to configure an L-Pad over a single power resistor.
I never wrote anything about amplifiers not handling higher resistance but when two 4 Ohm speakers are in parallel, which these are, it's possible to puke an OEM amplifier that may have been designed for higher impedance loads and having done car audio from 1978-1997 (I still do audio systems in residential, commercial and marine applications), I have seen many car amps and head units that stopped providing audio as soon as a second pair of speakers was connected. I also replaced many Bose systems that couldn't provide the output the car owners wanted, but the aftermarket speakers weren't particularly compatible with the Bose amplifiers. They sounded decent, but not loud.

Also, your description of what is needed WRT L-Pad calculators and math is a bit more precision than an OEM system with new speakers warrants, IMO. Precision is great, when needed- this will be fine without. I wasn't insisting on using L-Pads, though. However, I don't understand the recommendation to buy a selection of power resistors when you mentioned the excess cost of an L-pad. What should he do with the resistors that aren't used? :D

I don't fit in Miatas, but they're cool cars- I had an RX-7 and it was great. Unfortunately, I no longer fit in those, either. If I did, I would get another one.
 
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highfigh

highfigh

Seriously, I have no life.
I have to ask if you can explain why the left side dash is too loud and the identical speaker located right side dash is not too loud!?
The dash speakers should be at the same level given identical speakers!
I could understand both dash speakers being out of balance from the door speakers since they likely have different efficiencies, but if the right dash speaker is a reasonable match for the door speakers, something seems wrong.
The dash speaker positions are very different and even though they're the same size, they sound different because the direction, sound path length and shape of the windshield directs the sound to different places. The driver's seat is next to the door and the passenger side speaker is beyond arm's length. If his head was in the middle, they would be the same level. Even with only door speakers, the driver's side is usually louder.
 
P

pewternhrata

Audioholic Chief
The dash speaker positions are very different and even though they're the same size, they sound different because the direction, sound path length and shape of the windshield directs the sound to different places. The driver's seat is next to the door and the passenger side speaker is beyond arm's length. If his head was in the middle, they would be the same level. Even with only door speakers, the driver's side is usually louder.
Driver side will typically be louder for the driver and passenger side would be louder for the passenger. The speakers in the dash are most likely a different ohm than the doors hence why they are louder. If a passenger is riding along, the passenger door will sound even quieter to the driver. If the ohms are different between dash and door he would need to match those values. I've done quite a few systems in cars and sometimes it can be a pain to get it right. Would be helpful to know more about the setup, amp headunit speakers with model #s, factory wiring or all ran new. I had a buddy replace door and dash speakers both 'full range' after he played around he opted for components. Tweeter in the dash mid in the door. The xover had 2 outs for the tweeter one increased dbl level by 2 which was awesome
 
highfigh

highfigh

Seriously, I have no life.
Driver side will typically be louder for the driver and passenger side would be louder for the passenger. The speakers in the dash are most likely a different ohm than the doors hence why they are louder. If a passenger is riding along, the passenger door will sound even quieter to the driver. If the ohms are different between dash and door he would need to match those values. I've done quite a few systems in cars and sometimes it can be a pain to get it right. Would be helpful to know more about the setup, amp headunit speakers with model #s, factory wiring or all ran new. I had a buddy replace door and dash speakers both 'full range' after he played around he opted for components. Tweeter in the dash mid in the door. The xover had 2 outs for the tweeter one increased dbl level by 2 which was awesome
First, aftermarket and most other car speakers are 4 Ohm, for the reason Johnny2Bad mentioned- they're used in a 12VDC electrical system and that limits the amplifier's output, although that's not as much of a problem as it was in the beginning of solid state car radios. You can't achieve more than 12V of output without some kind of additional circuitry and that voltage limit means 6V, peak to peak at 100% efficiency. In real world conditions, a low powered radio was able to output around a whopping 3 Watts/channel until they wire able to miniaturize and use a stereo chip for each channel, which was good for about 14W, at fairly high distortion. It was also a good way to see smoke when people would leave the speaker negative wire connected to the car's body or combine the negative speaker wires.

The system in this thread is OEM- some of those don't even have a balance control.
As I posted, I did car audio for 20 years and installed many competition systems- balancing the levels is easy if the amp has independent controls for each speaker, but that still doesn't fix the problems with time coherence- the difference in distance causes the same phase cancellations we see in home theaters, just at higher frequencies and messes with the imaging.
 
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pewternhrata

Audioholic Chief
@highfigh what's your take on running 2 speakers off one output? Did he run series or parallel...The dash speakers and door speakers are tied together as the fronts and the rear are the the rears. So, six speakers...running 6 speakers off a 4channel amp. Of course you could but a little more info on the setup could be beneficial. Yes most are 4ohm, but most is not all, again do we know for sure they are both 4ohm. Not saying balance will be a cure all, and not saying an l-pad is bad idea. Just appears to be something else going on...but again I'm no expert.
 
highfigh

highfigh

Seriously, I have no life.
@highfigh what's your take on running 2 speakers off one output? Did he run series or parallel...The dash speakers and door speakers are tied together as the fronts and the rear are the the rears. So, six speakers...running 6 speakers off a 4channel amp. Of course you could but a little more info on the setup could be beneficial. Yes most are 4ohm, but most is not all, again do we know for sure they are both 4ohm. Not saying balance will be a cure all, and not saying an l-pad is bad idea. Just appears to be something else going on...but again I'm no expert.
The only car speakers I saw that weren't 4 Ohm were subs that were made to be used in a multi-driver configuration, so they were 2 or 8 Ohms. Door, dash and rear deck speakers were all 4 Ohm, because they weren't made for custom and even if they were, amps used in a custom system can handle 2 Ohms, so it really made sense to stick with 4 Ohms because it was more common to use one speaker or set in each corner, with maybe a mid-bass in front (mounted low) to create a more similar path length. The electronics at the time really couldn't time-align the system the way a DSP can, so we had to do it with placement.

The OP wrote that he replaced the door and dash speakers- that tells me they were parallel and the OEM amp or head unit is made for a non-standard impedance. If you look at older GM speakers, you would see 9 Ohms' stamped on the magnets. Connecting 4 Ohm speakers would usually work if it wasn't cranked, but in the case of the Chevette radio, adding another pair of speaker would cause the sound to stop completely, until the radio had the correct load.

Running two speakers in series results in the output SPL of the average of the two- that would probably fix the level problem at the dash, but reduce the output of the left door speaker to the point of being noticeably lower.
 
hemiram

hemiram

Full Audioholic
I'm still confused as to why anything would change just because of speaker replacement. I have 3 small speakers in the dash of my 2010 Challenger, and I changed them to JL's that dropped right in for a major sound improvement with a tiny loss in output. One tap of the fader towards the front and the volume balance between the front and rear was back to what it was, with a much smoother top end.
 
highfigh

highfigh

Seriously, I have no life.
I'm still confused as to why anything would change just because of speaker replacement. I have 3 small speakers in the dash of my 2010 Challenger, and I changed them to JL's that dropped right in for a major sound improvement with a tiny loss in output. One tap of the fader towards the front and the volume balance between the front and rear was back to what it was, with a much smoother top end.
You mean by ONLY changing the speaker's location? The windshield is curved, so it focuses the sound in a particular area- remember parabolas and hyperbolas in math class? They're different kinds of curves, but they have a focal point, just like any symmetrical shape of that type. The problem- the windshield isn't a symmetrical shape and the curve tends to be at or close to the outside of the speaker's cone. That could be construed to be done so it fills the middle of the car with sound, rather than bouncing it into the face of the person sitting in the nearest seat, but if the speaker were moved toward the center, everyone sitting in the front seats would hear a gap in coverage, somewhere.

Your speakers are smoother than the original ones and less sensitive, so they don't quite fit the definition of "matching" the rear speakers but that's OK. If the OP's speakers sound better than the OEM ones, they're still an improvement but because the frequency response has differences, the left one sounds louder than it should. It's possible that the OEM dash speakers are limited in the lower mid region, by design and the new ones aren't. If the front speaker specs weren't known, finding an exact match WRT performance wasn't the basis for choosing the replacement speakers and it was based on what would fit, the sound WILL change.
 
hemiram

hemiram

Full Audioholic
No, the speaker locations haven't changed (from the OP's post, it seems that he replaced the dash speakers and put the new ones in the original locations), and I would be shocked if he didn't put them in the same holes. I would assume, maybe incorrectly, that the replacements are a matched pair, so I don't see why just plopping in new speakers would result in an imbalance as the OP is having, since the right one should increase in volume too. The only way I would see that happening is if the tweeters are adjustable as far as angle goes and the left one's output is bouncing off the glass directly at the driver's ear. I've been in a lot of cars with half assed car stereo installs over the years and never seen any major imbalance after a speaker swap that wasn't able to be diagnosed as a bad speaker or wiring/amp issue. A lot of these installs were comically bad. My favorite was a friend's brother who "installed" 6X9" speakers by simply setting them on the rear deck, not seeming to realize they would become missiles in a wreck. He was lucky, when it flew, it missed his head and just went through the windshield. The speakers being ruined was the least of his problems. His really nice '71 Chevelle SS was gone.

On my car, a 2010 Challenger with the "Sound Group II"Boston Acoustic 7 speakers and sub, the back speakers do so little I didn't bother changing them. My friend spent a couple of hundred bucks on the rears to swap them to JL's and the slight improvement was really only audible when you had the fader set "wrong" and the back speakers were way louder than the front, which sounded pretty bad. I took some of that money and put some sound deadener sheets in the doors to quiet down road noise, and a little in the dash to quiet the buzzing it gets in the colder months until the car warms up inside. My friend and I kind of take turns being guinea pigs with mods and stuff. I was the first one with the dash speaker swap, he was the first with the rears. The results, or lack of them, made me pass on doing it. Most of the time, going back 3 vehicles what one does, the other one does too.
 

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