Educate me on car audio, help with upgrades

Yuriman

Diamond Member
Jun 25, 2004
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Looking to do some audio upgrades on my Honda Insight. It's currently very "cobbled together".

What I have:

Two cheap Sony 40w RMS 6.5" speakers in the doors, powered by head unit, came with the car.
Two cheap Rockford Fosgate Prime 45w speakers I added to the deck behind the two seats
A Bose home subwoofer I found on the side of the road with a dead amp (which I cut off), under the carpet in the hatch - looks a lot like this.
A 240w RMS Kenwood 4 channel AB amp (KAC-8401) I brought from my previous car, powering rear speakers and sub

85hz Crossover
Dialed back ~1500hz range by head unit's equalizer due to it being way out of line from the front speakers

The rear speakers sounded significantly better than the fronts when all of them were powered by the head unit / before I found the sub, to the point I almost didn't want the front speakers. I'm not sure if this is because of the better "enclosure" provided by the deck vs the doors, or if it's the speakers themselves, but that's why I chose to put the rears on the amp with the sub. I couldn't change the fronts out at the time because the door panels prevented anything but a low profile speaker from being installed, but that's resolved and I can install whatever now.

The sub sounds "fine". I'm not a bass head, I listen to a lot of indie and acoustic music and tend to keep the bass low enough that it fills in, but doesn't overwhelm. It serves this purpose, but I'm open to thoughts/criticism.

Over the weekend I mounted my door speakers to the door frames, rather than to the plastic panels, and that seemed to improve the very anemic upper base the fronts provide and mellow out the overwhelming 1500hz +/-.

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At this point I'm not sure what would be the most cost effective way to make it sound a little better. A friend would be willing to sell me his class D Alpine PDR-F50 amp for pennies on the dollar. On paper, aside from more watts and an original price tag 4x as high, it looks to have worse THD, signal to noise and frequency response than the significantly cheaper Kenwood amp I already have. I understand class D amps are more efficient, and what's on paper isn't always reflected in the real world. I'm not sure what I'd do with two 4-channel amps. I'm considering swapping the Kenwood out with the Alpine for the door speakers (and throwing it up on Craigslist) to see how it sounds, and then either dedicating the Kenwood to the sub, or replacing it with a small 1/2 channel D amp for the sub.

Regarding the sub, I would consider replacing it with something a little larger, but I don't want a terribly large sub. I believe the Bose unit has a 6.5" woofer, maybe an 8"?

I've looked around at replacement 6.5" door speakers. A lot of reviewers and sites seem very reluctant to call one speaker better than another, and instead imply buyers should just listen to them. That's hard to do when ordering online. It seems like more expensive speakers tend to have higher RMS watt ratings but otherwise look no better on paper, and frankly I have little first-hand experience with car speakers, so any specific suggestions would be helpful. What do I need to know when selecting door speakers? If I were to order today, I'd likely try out some Infinity Reference speakers.

Thoughts on putting a few strips of dynamat knock-off into the door panels?

Other ideas?

oDQ1xJ3l.jpg
 
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monkeydelmagico

Diamond Member
Nov 16, 2011
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Whoa. That is rather cobbled together isn't it?

1: Spend the time and effort to get the fronts sounding good. Reasoning: When you go to a concert the music comes from the front. Same with your home stereo. Putting so much power into the rears might make for a loud system but not necessarily a good sounding one.

2: I suggest a component setup for the front. I find them to be far superior to full range speakers. A component setup for the front is the first thing on my shopping list when I upgrade a car stereo. I've used the Infinity Reference you mentioned and found them to be good. Very good on frequency separation. Can be a bit harsh. Boston Acoustics are warmer toned to my ears. I like that better.

3: I would run your current 4 channel amp to the four full range speakers. You need to have your head deck able to control each speaker independently while maintaining proper gain throughout the volume range. Hard to do if you are sending half the signal to an amp and the other half direct to the front speakers.

4: Forget the sub or buy your friends Class D to power it. A sub is the last thing I shop for. Why you might ask? Because in some cars I don't need it. By the time I have set up a nicely baffled 4 way component system with a decent amp behind it the sound is perfect without the need of any additional bass. Of the 6-8 cars I've owned and upgraded only 2 have ever really "needed" a sub. Both were full size 4 door sedans.

5: yes dynamat in the front doors, especially if you amplify them, will be important. Really important if you run them full range. Fairly important if you cross them over and push the bass frequencies to a sub.
 
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Yuriman

Diamond Member
Jun 25, 2004
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A lot of "component" speakers I see just have the tweeter moved away from the woofer. Does it really make that much difference, or should I be using three piece?

How important is it to completely isolate the front of the speakers from the rear? The door frames have plenty of holes in them, and the panels don't seal completely at the edges - there's an air gap.

Once bit that has me interested in with the D amp is the power efficiency. Any power savings are attractive in a car where I regularly aim for 100+ mpg, as a few hundred watts saved is actually (admittedly barely) visible in fuel economy. Plus, the Kenwood has fan in it which I can hear when the engine shuts off. Not too big a deal, I've been enjoying how it sounds for a few years now.

My subjective experience with the system as it is, is that there's adequate bass even without the sub when parked, but once I'm on the highway with road noise and the like, it sounds very inadequate, and the sub helps greatly to fill that in.
 

NutBucket

Lifer
Aug 30, 2000
27,034
546
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Moving the tweeter helps a lot. They're way too low by your feet. Is there a stock location further up on the door? If not the sail panel is an easy place for it.

I'll second the recommendation for Boston Acoustics. Very underrated brand but admittedly it's been years since I bought speakers.
 

Yuriman

Diamond Member
Jun 25, 2004
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Ordered a set of Infinity Kappas to try, and will be running them from my amp, sans sub at first. Will try getting some mat for the doors in a few weeks.
 

NutBucket

Lifer
Aug 30, 2000
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Sealing up the doors helps a lot...but just adding some dynamat-type material (there are various brands) to the door skin is already a good improvement. The metal is so thin it echoes.

Edit: looking at Boston's website it seems they don't make car audio anymore. Talk about the fall of a great company. I have something 5 pairs of their speakers from the early 90's. Budget friendly, US made and great sound!
 
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Smoove910

Golden Member
Aug 2, 2006
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I'd amplify your front door speakers, and as suggested, go with a pair of components (I have Image Dynamics in mine). I'd also only run your rear speakers off the deck. You don't need to amplify sound coming from the rear, it's only used for 'fill'. Dynamat your door's exposed metal surfaces that reside behind the door panel. There's also a spray in deadener that I use that you can spray inside your doors that helps deaden too. Once you get the front stage setup to sound how you want, then add your bass.

On a side note, keep in mind Class D amps are usually good for bass. Class A is what you want for your highs.
 

Midwayman

Diamond Member
Jan 28, 2000
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Does your HU do time alignment? If not a sound process might be what I do next. That made the biggest difference when I upgraded my car audio. Aside from that component fronts help. Treble is very directional. Tweeters directly facing your listening position help alot. You can also get angled mounting rings to point the mids towards you face. A little sound deadening always helps too. I'd check out these guys https://www.b-quiet.com/ they are a lot cheaper than dynomat.

Just keep in mind car audio is a bad place to spend money unless you have a really quiet car.
 

jtvang125

Diamond Member
Nov 10, 2004
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As already mentioned concentrate on your front stage. Ditch those coaxial speakers and go with the best component system your budget will allow. The woofers, tweeters and crossover will be of much better quality. The tweeters on most coaxials are a joke anyways. Bridge the kenwood amp to feed the set as much power as you can. Seal and dampen the door panels as best as you can. Don't worry that it's not completely sealed because that's impossible to do. Just get the large openings.

If the Alpine is within your budget then get that to power the rear speakers and bridge 2 of the channels to power the sub. Set the rear fader on your deck to have a more front bias. Trying to get good SQ in a car is a very expensive chase.
 
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Yuriman

Diamond Member
Jun 25, 2004
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Over the weekend I installed four Infinity Kappa speakers, re-ran most of the wiring (14 gauge for speakers, 12 gauge to power the amp).

I started by just replacing the door speakers and leaving them powered by the head unit, and frankly the Infinity Kappas were a phenomenal upgrade over the Sony Garbage™ I had there. I found I was hearing detail that was previously entirely lost, and was able to flatten the equalizer.

Next, I replaced the rear speakers. I had to get out my jigsaw and make some "modifications" because of the depth. From these I ran 12 gauge braided copper to the amp. I then replaced the ground and 12v lines to a new amp (Infinity Reference) with 10 gauge. The 12v line runs directly from the battery (fused) and through a grommet in the firewall. The ground is next to the amp, under the passenger seat.

After connecting the RCA cables from my amp, I immediately noticed a lot of hiss and high pitched whine which wasn't present without them plugged in. Turning on some music, I noted the rear speakers sounded like complete garbage. Aside from the whine, low frequencies were completely garbled, worse than crossed phases, more like blown-speaker sounding.

-I pulled the Infinity amp out and put my older Kenwood back in, and while the whine wasn't as loud, low frequencies still sounded garbled and awful, so it wasn't the amp. My guess is that the Kenwood amp's different design minimizes whine somehow (class D vs AB?)
-I tried switching the phases to the speakers, which made no difference.
-I tried using both front and rear outputs from the head unit, and both front and rear inputs on both amps.
-I tried playing with gain, HPF and LPF on the amps.
-I tried powering the amp through the 12v power socket (different +12v source and ground) and that made no difference.
-I pulled the dash apart and stretched out my RCA cables, which were really too long by a lot (10ft?), and frankly are garbage cables. With them away from everything else (EMF) and not bundled up, the whine was reduced on the Infinity amp but the low frequencies did not improve and still sounded blown out. I have on order a pair of correct-length shielded beefy RCA cables, but I doubt that will solve this.
-I cut and spliced the RCA cables down to a very manageable ~24 inches, no improvement.
-I tried connecting the amps to my phone as a source, rather than the head unit, and still the lows sounded bad.

So, I believe I've ruled out a bad amp since they both do it. I've ruled out head unit as a source of garbled audio by using my phone as source. I've used different cables and swapped phases. I've tried a different power source. I have not yet tried jumping the amp by shorting the remote to +12v, and running it from battery while the car is off (so no electronics possibly interfering), or using the old speakers, because pulling the rear deck apart is a real chore. The speaker box was seemingly unopened though, and both left and right speakers sound the same, which makes me inclined to believe they aren't both blown new speakers from the factory in the same box. Everything below maybe 150hz is just horribly distorted and garbled though.

I think my approach when I get home from work today will be to power the amp with the car off, and also separately from a large PC power supply, try using my phone as source, and try both new and old speakers to see if perhaps the pair of Kappas I got were defective. Any troubleshooting advice is welcomed.
 
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Yuriman

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Jun 25, 2004
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Reading around, it sounds like ground loops generally cause hiss and whine, but I'm not able to find anything on why I'd have severe distortion in low frequencies, even with gain set to minimum.
 

Thebobo

Lifer
Jun 19, 2006
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I was going to do this to my blazer and add a sub but I had a hearing test and I have already lost about 10% of the higher ranges. Going to be the old fogie here but you already know that loud music/noise will cause hearing loss. The Louder the shorter amount of time it takes. And its not temporary. Is it worth it so that someone 20 cars away can hear what you listening to? When your young yep!

Anyhow looks like a cool project I've wanted a sub in my truck.
 

Yuriman

Diamond Member
Jun 25, 2004
5,530
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Think I've got it resolved. I sat outside for a couple of hours playing with them, and turns out it was both rear speakers. I put my older Rockford Fosgates back in the rear deck and they sounded fine. Powered the rear speakers again by the amp without any enclosure and they both had distorted bass. Pulled one of the Infinities from a door and tried it on the amp just to be sure, and it was fine. Looks like I'll be exchanging them.

I was going to do this to my blazer and add a sub but I had a hearing test and I have already lost about 10% of the higher ranges. Going to be the old fogie here but you already know that loud music/noise will cause hearing loss. The Louder the shorter amount of time it takes. And its not temporary. Is it worth it so that someone 20 cars away can hear what you listening to? When your young yep!

Anyhow looks like a cool project I've wanted a sub in my truck.

It isn't about volume, but clarity. Have you ever bought a new seat of headphones or speakers, and noticed particular character in music that was previously absent? Like, being able to hear the scratching of the bows on strings in a piece of classical music?

That, and not having any major dips/gaps or peaks in frequency response. This is the frequency response graph of the studio monitors I use on my computer at home:

iloud-micro-monitors-frequency-response.jpg



Comparatively speaking, my car speakers are all over the place.
 
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rstrohkirch

Platinum Member
May 31, 2005
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Do you have any other questions outside of the troubles you were having with the rears? This is a on/off again hobby of mine but I'm unsure of what your actually asking in your OP. I don't see any goals, budgets, etc.
 

Yuriman

Diamond Member
Jun 25, 2004
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Ground loop isolators came in today, and improved sound significantly. I also got the fronts and rears powered by the amp, and am very pleased by the improvement.

As for questions, how about, what way do you recommend adjusting gain on my amp? And, What do I need to know about dynamat and its knock-offs? Does the thickness of it matter?
 

rstrohkirch

Platinum Member
May 31, 2005
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For basic gain level settings you would generally use a sine wave. You want to maximize the signal through the chain so on your HU, or whatever your using as a source you want to set gains using max volume. If you don't know whether or not the source your using clips at max volume then back off max volume around 10%. Then play a sine wav and slowly turn up the gains from zero until you hear distortion in the tone. Back off a little and your done. Try something like a 250hz sine wave and wear ear protection.

In regards to Dynamat, the point of CLD tiles on a door is to add mass to the sheet metal and change the frequency at which it resonants. The first thing you need to do for a door is to seal off any large holes. You can do this with some 1/4" plywood. You cut it to shape and screw it to the sheet metal. That way if you ever have to do repairs in the door you can still easily access the cavity. Then you go through with your CLD tiles and get a coverage rate of around 50%. You do the same thing to your door card. You also want a good seal around the driver in the door. Do all of this and you'll get improved response. You can spot attack areas by running a tone generator and moving up through the frequency band till you hear things resonating and then try to fix it.

This is an average quality CLD tile at a good price. Not the best and not the worst but should work well for you. https://www.amazon.com/Noico-deaden...UTF8&qid=1526495775&sr=8-1&keywords=cld+tiles
 
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NutBucket

Lifer
Aug 30, 2000
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IMHO plywood is a hard way to seal holes. I used mesh...like mesh you would use for lathe and plaster. Then I covered that with the rubber mat and Ensolite.

http://www.raamaudio.com/pages/How%2dTo.html

That's the stuff I used about a decade ago. Luckily I haven't had to get inside the door since! I only sealed the fronts IIRC. I applied the mat to the rear door skin only as I left the stock rear speakers (hu amplified) for some fill only.
 
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rstrohkirch

Platinum Member
May 31, 2005
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Whatever way you prefer. Sealing up the large holes in the door goes a long way towards preventing front and back wave interaction which can only give better results.
 

Yuriman

Diamond Member
Jun 25, 2004
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For whatever reason, the new amp seems a lot more susceptible to electrical "noise" - I grounded it in the same place as the old one, with larger cables. While ground loop isolators on the RCA cables got rid of the hiss, I'm hearing what I'm fairly certain is the spark plugs (or maybe injectors) firing whenever the engine is running. I hadn't noticed it before because I set the system up with the engine off. What can be done about this?
 

rstrohkirch

Platinum Member
May 31, 2005
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First you need to make sure you're amp ground is legit. It should be bare metal and have low resistance to the frame of the vehicle. Use a multi-meter to check resistance and continuity between ground point and the frame. Make sure RCA and power wire to the amp are not next to each other. From there you need to isolate things. If you pull the RCA from the amp does the noise still show up or does it go away. If it goes away then you can test running a ground from your source to the same spot as the amp. You can tell if it's up the chain by using something like you're phone with a 3.5mm to rca cable into the amp. This will isolate the source. If noise persists it's a ground, vehicle, amp issue. Vehicle issue would be something like bad plug caps/wires arcing to frame.
 

Yuriman

Diamond Member
Jun 25, 2004
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I'll check those when I'm home. No plug caps or wires though, it's coil packs and from the sound of it, it's all of them - I can hear the correct number of ignition events for a 3 cylinder.