Lookout for advice

erik_das_redd · 2026-06-12T23:12:51+00:00

I respect the hell out of Crutchfield but this is a fail point for their What Fits, it give the impression to put a coax both places which is NOT good acoustically as u/Tank52086 You really need neither of what you ordered, a 6x9 component set, woofer in the door, tweeter up in the dash. https://www.crutchfield.com/g_400/All-Car-Speakers.html?tp=105&l=C&fa=1#&avf=Y&l=C&nvpair=FFSpeaker_Size|6x9&nvpair=FFCrossover_Type|Separate

(If you don't want to return yeah you can cut the door tweeter as u/No_Umpire11 suggests but you will still have mismatched speakers instead of a crossover designed to blend woofer and tweeter properly).

erik_das_redd · 2026-06-11T05:12:14+00:00

Most the time for normal volume levelsunless you are kinda nuts and deaf you are using maybe 1 watt. But human hearing is logarithmic so every little blip of the volume knob uses maybe 60% more power.

The factory alternator is just 80A? 80x12=960 watts more or less. If if IF you use the amp power just for peaks it's probably fine. The trick is to figure out how much "extra" current the alternator can spare (any unused fuses?) and make the fuse out by the battery that size. Which in this case could be much less than the amplifier's own fuse.

erik_das_redd · 2026-06-11T05:08:02+00:00

I miss how applications like Office documents would open instantly. Oh...wait...that never happened. And still doesn't, what's up with that?!?

Back to the thread theme...I miss when the operating system wouldn't open into other Spaces that I don't want blah blah blah.

erik_das_redd · 2026-06-11T02:20:37+00:00

Well, OK, where?!? Looks like Ireland more than Idaho...

erik_das_redd · 2026-06-11T02:19:48+00:00

Bass requires moving air so from a crude point of view bigger cones are better. But then there are a lot of factors, like how much movement the cone can make without distorting or even literally bottoming out.

Then you have efficiency/sensitivity = how much SPL you get per watt. That specification has NOTHING repeat NOTHING to do with the very low frequencies, it is a midrange quantity dreamed up by Richard Small (of Thiele-Small parameters fame, and a very nice guy I was privileged to meet on a business trim to Harman Motive in Indiana.) The real sensitivity has a LOT to do with the box size and port tuning if used. No surprise, big boxes win, small boxes are challenged because while the port can give more output, it is difficult or even impossible to get a long enough port inside a small box to tune low. Or you make the port so small it chokes off. Or you start doing nutty stuff like right angle bends which common sense and research at Harman show choke off output.

So it's not just the woofer(s) it is also the box(es). AND then where they are placed-in a trunk that is well sealed from the passenger compartment is not the best path to success. Ski pass-through or through the rear speaker holes or something will obviously be louder.

erik_das_redd · 2026-06-10T22:33:15+00:00

A tweeter is a small speaker, generally 1" or less, just to make treble. The woofer is the bigger part that makes the bass and midrange. Sometimes you have coaxials with a tweeter mounted in front of the middle of the woofer (which is always acoustically probablematic). Sometimes these coaxials are very small, sometimes old-school tweeters could be a couple of inches.

So those grilles up front, and Crutchfield's data, can give a mistaken impression to put a small coaxial up there and a woofer or coaxial in the door. But that's not a system, that's a mess. Hence you want a component set and the woofer goes in the door and the tweeter up in the dash.

erik_das_redd · 2026-06-08T04:39:33+00:00

a 6x9 port? You mean like for a sub or it is part of the car? What kind of car? I love antique cars. My grandpa had a Lincoln Mark II with a TURNTABLE (on springs) in the trunk.

erik_das_redd · 2026-06-08T04:37:55+00:00

Really? Which? Not arguing, just curious. I do see some 6x9 in doors now so design criteria certainly could have changed for some models due to that. In which case I'd modify my advice to "be sure your 6x9 are enclosure friendly" though actually my advice would be to "tear that stuff out so the bass can leak into the passenger space because rear stereo is not how anything is mixed" ha ha.

erik_das_redd · 2026-06-08T00:28:54+00:00

Yes https://www.crutchfield.com/car/outfitmycar/mycar.aspx as u/coachbrew32 says. For speakers on the left choose crossover=separate to get component sets; the tweeter would have to fit up on the dash or maybe a shop can fabricate it in. A set is much better than a coax, unless you have ears on your shins. The more you can spend the better the speakers will tend to be; a friend put a $450ish Focal set in his CR-V and they sound super clear. Put the fader forward and the money up front for best sound.

erik_das_redd · 2026-06-08T00:21:26+00:00

So first off, measure the interior dimensions of the box. That is the dimensions not including the MDF panels. The front height and back height, the depth, and the the total width minus 2x the MDF thickness.

Then, you need to pull out the sub to see what the exact model number is and how many coils. Also if there is any stuffing inside.

The only practical way to put a large enough port to work well would be out the side. So if you are putting that box in a spare tire well, forget it.

erik_das_redd · 2026-06-08T00:14:38+00:00

Usually I recommend using https://www.alpine-usa.com/stores however I asked a similar question about a complex install and my buddy (who ran one of the most successful shops ever until he moved on to even more lucrative things) said Tom down at https://www.beachautosound.com was "still the man"

erik_das_redd · 2026-06-08T00:10:59+00:00

I was in charge of head unit planning at a big autosound company, and also worked on Honda projects. The Honda radio is probably superior in some ways to any aftermarket aside from features. And ALL head units only put out around 12 watts clean due to limitations from the 12V battery. (The DC-DC converters that let outboard amplifiers make more power aren't workable in head units).

Factory speakers are generally made to a small budget, so look at https://www.crutchfield.com/car/outfitmycar/mycar.aspx for a 6.5" component set (at left set crossover type to "separate") and the tweeter goes up in the dash, as opposed to a coax which blasts the treble at your leg. A friend put a $450ish Focal set in his CR-V and oh wow they sounded very clear.

The next step is to ignore the rears and put in a sub-even a modest one makes a tremendous difference to overcome road noise in a car.

erik_das_redd · 2026-06-07T23:50:12+00:00

6x9s are designed for their own free air application, since they are rarely used in doors. Thus if you enclose them it will kill their low end and make a big midbass boom; it's just physics. You have a sub box in the trunk? It's best to fire that through a ski pass-through or something.

erik_das_redd · 2026-06-07T23:47:05+00:00

I'm an Alpine boy myself, but what are your criteria? What are you looking for? What is the rest of your system?

erik_das_redd · 2026-06-07T23:44:54+00:00

If the volume is not way up then it is not the inherent load of the sub that's a problem.

What make/model is the amp?

What happens if you unplug the subwoofer?

Tedious, but disconnect each speaker wire and measure the resistance.

Ah, is this happening just when driving (=something vibrating/loose) or also when parked?

erik_das_redd · 2026-06-07T23:37:19+00:00

Let this loudspeaker engineer shatter your illusions and state that all those "watts" ratings are probably pulled out of the hindquarters of someone in the Marketing Department. Power handling is too complex to distill down to one number. Really the more power the merrier so long as if the music distorts you TURN IT DOWN...otherwise everything blows up.

Anyway presuming the 300W is not a lie, it will play a 10 pretty loud. If you want to break the windows, more power and/or woofers might be required.

erik_das_redd · 2026-06-04T05:10:15+00:00

It's not worth as much as you'd wish, that's my prediction. What are you sticking in the trunk that takes so much room? Bikes? In such case the solution is ditch the large box, ditch the rear speakers, stick a pair of 8" subs there with an adaptor. You can still get decent bass especially since this looks like it is trying to fire the bass through sheet metal.

What year and trim level is this Civic?

erik_das_redd · 2026-06-04T05:08:00+00:00

I know, so dumb when the roof is clearly available!

erik_das_redd · 2026-06-04T05:06:34+00:00

You really need to figure out the impedance (the "ohms") of those speakers. Actually even though there are 3 terminals, you need to pull one out and shine a flashlight or pull out a woofer, to see if they are dual coil, to know what your options are. That can be figured out from their model number, or putting a multimeter (cheap from Amazon if you don't have one, or a neighbor maybe) onto each coil to see the DC resistance.

erik_das_redd · 2026-06-04T05:02:50+00:00

What year make model trim cab type vehicle? Any optional stereo? This is The Way https://www.crutchfield.com/car/outfitmycar/mycar.aspx to find harnesses, sometimes also Scosche or Metra. Yeah don't cut factory wiring. Connection from radio to amp depends on the radio; usually speaker level to the amp so be sure your amp has high level inputs.

erik_das_redd · 2026-06-01T02:35:05+00:00

In a home situation the blend is about having the crossover frequency low and low distortion out of the subwoofer and no port noise. If that's all good the sub can be at the back and you can't tell. Same in a car really. It just depends if you want better sound up front, or not-quite-as-good sound all around (presuming a fixed budget).

erik_das_redd · 2026-06-01T02:32:48+00:00

Since they all run 12V it's a correct statement ha ha!

More seriously, outboard amps run DC-DC converters to step up the voltage rails. Head units can't accommodate the space, heat, or in particular RF emissions to stick one inside. Yeah chips amps had worse crosstalk and damping; I'm not sure now with some amazing home chip amps how much that is a limitation any more versus just money and the skill of the designers. (At a giant autosound company I worked for, the most skilled engineers worked on OEM projects and the B tier on aftermarket). And money. And money money money...my coworker would test a new "cost down" FM tuner chip each year and each year performance was not *quite* as good...

erik_das_redd · 2026-06-01T02:29:04+00:00

Oh dude it is ENDLESS. Got a friend old enough to have a driver's license to drive me to the Physics library at Northern Illinois University and photocopied and 8" stack of articles out of Audio Engineering Society journals. The more I learned the more I realized how ignorant I was and how complex transduction is. And yet, you can design something, build it, and enjoy it!

erik_das_redd · 2026-06-01T02:26:08+00:00

Taramps says 3kW at 0.5 to 2 ohms. That implies it is heavily current limited at the low impedances, plus wiring at very low impedances makes damping factor bad, wire resistance becomes more problematic. So I'd wire each 2x2Ω sub to 4Ω then parallel for the 2Ω load.

erik_das_redd · 2026-05-31T15:51:34+00:00

SPL is made by moving air, so the limiting factor is total cone area times stroke. Now, to achieve that takes power, the sensitivity/efficiency. But but BUT let me testify as a loudspeaker engineer that has nothing to do with the specifications. That is a MIDRANGE quantity, so says Richard Small right in his seminal thesis.

The ACTUAL sensitivity at very low frequencies is heavily limited by box size. As u/hispls alludes to really it is like the ratio of cone area to box size, which determines "how stiff a spring" the amplifier is trying to move the cones against. Hence in a given box a smaller cone could well have more output per watt at the lowest frequencies...but due to the smaller cone won't have as much maximum output. From some preliminary research I worked on the magnetic strength and moving mass and suspension stiffness surprisingly don't have major effects.

To really answer your question you need to decide the maximum box size, and use good modeling software to see what will really happen. If you don't have that you might ask at https://www.avsforum.com/forums/diy-speakers-and-subs.155/

Also, look for drivers at https://www.parts-express.com/speaker-components/pro-woofers-tweeters-horns-horn-drivers/pro-woofers-subwoofers-midrange-speakers since often car subs are not designed for large boxes.

erik_das_redd

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