Car speakers in home theater!

They are engineered completely differently and I found out trying it myself quite a few years back. I did not have satisfactory results. Car audio speakers are designed to sound good in tight spaces, not open ones, like a living room.

Design wise, it is not possible for them to sound good in open rooms. I'd like to see some room charts to prove otherwise though.

OP is right....his man cave is the size of his car cabin.

Clemenslee, from what I understand, car speakers are designed with an infinite baffle concept. Not so for room speakers. But I am sure one can make it work with a capable speaker set.

Car subwoofers are designed to:

1. Make use of the automotive "cabin gain", where low frequencies are "boosted" because of the small size. T/S parameters typically shoot for an F3 in the 60Hz range for a smallish sealed enclosure.

2. Survive the abuse thrown at them by a typical user.

3. Survive the harsh automotive environment...temperature swings etc.

4. Appeal to the consumer with fancy surround shapes, dust cap logos, frames, magnet covers...etc...


Home subwoofers are designed to:

1. Make use of the living room "room gain", where low frequencies are boosted much less than a car. Typical T/S paramters shoot for an F3 of 30ish Hz. in a 60 to 90L sealed cabinet...or lower in a vented cabinet.

2. Low distortion-long excursion without the flashy graphics and plastic.

So I'd say they're not really designed the same. The only similarities would be the physical parts of the speaker itself.

There's no difference between car sub drivers and home sub drivers other then the enclosure designs they're put in. Many "car" brands are very well regarded by DIYers. If you're designing and building your own boxes there's no reason you cant use a car sub if it models well.

What you've got going on is completely different then subwoofer design. A crossover makes the speaker, and none of those speakers are designed to be placed out in a room.

But hey, as long as you're happy that's all that matters.

Did you have Larry the Cable Guy help with those?

Not to bust your bubble or anything, but for about 300 bucks, you could have got yourself Polk Audio CS2 center and 4 Monitor50 towers and had yourself a pretty decent setup. Speakers designed for car audio are just that. You are somewhat correct in that a speaker, in theory, operates on the same principle, but from a design standpoint, there are many different applications that call for a different approach to get the desired results.

I applaud your effort, but i think you would do much better if you put them back in your pickup truck and got something designed for the task at hand.

Building an enclosure is much more than building a box to put the speaker in. The dimensions of a speaker cabinet must be in accordance with the way the crossover is designed. As someone else stated, the car speakers you're using are probably designed for an infinite baffle.

Backwards you have it. The enclosure is driver spec dependent, not the other way around. Autosound drivers tend to have high Fs and high Qts figures. They're made that way to work in small sealed boxes and large untuned enclusures because that's what will fit in a car. They trade off both broadband sensitivity and low frequency response because with short driver to listener distances and cabin gain of a car they can afford to do so. Remove them from their intended environment and those trade-offs become shortcomings.

Bottom line, a well designed autosound driver is made to work well in a 125 to 200 cubic foot listening room, a well designed stereo/HT driver in a 1000 to 3000 cubic foot room. If there was no reason to make autosound and stereo/HT drivers with different specs there would be no such thing as autosound drivers.

Bill, I've modeled dozens of autosound drivers, the manufactuers recommended enclosure sizes are almost never the same as the ideal enclosure based on TS parameters (check out Rockford Fosgate for example). Also, what says a driver that wants a smaller box with a steeper roll off cant be put in an alignment that nets 20hz output?

The biggest difference between auto and home drivers is looks of the drivers, plain (home) vs flashy (auto).

Here's my car subs in a small sealed box with the O-Audio 20hz filter (at LP in room)



Here's the modeled response showing max output before the boost compresses.

I am inclined to agree with you on car audio/home audio subs, but the OP is using coaxial/three-way 6x9 speakers placed inside boxes for HT. These speakers are designed differently than a sub.

Agreed. I pointed that out in post 11 after he posted pics

Hey, if Bose can put 5-1/4" woofers in a box with a convoluted maze and attempt to make it sound like a sub-woofer, you sure can do it better

When you measure in-room you're measuring the room response as much as, if not more than, the speaker response. You can't draw any valid conclusions from that.

You'd be hard pressed to find any transducer engineers or professional loudspeaker designers to agree with you on that one.

Yes the room response is a little ragged, but look at the basic curve. This is a 22' x 22' x 8' room. I'll stick with my measured response matching my modeled response, in addition to what my ears tell me, as proof enough that you can use a "car" sub in a home lol.

You can also check the "master sub index" thread in the DIY section for many other builds using "car" subs. I'm really surprised you are arguing this given the number of successful builds...

That would be because I am a professional loudspeaker designer, and I work everyday with transducer engineers who design drivers, auto sound, hi-fi and pro-sound.

I'm aware of who you are Bill, but that doesn't change the results.

In a sense, you are both correct. Many "car" subs do indeed have higher Fs and are designed for very small enclosures, with the idea that a cars interior will produce significant gain at LF to compensate. However, not all "car" subs fit that criteria. As you point out (and obviously Bill is unaware of), there are several that do indeed have all the (T/S) parameters necessary (including low Fs) to be used in a "home" environment.
As long as you can disguise/hide the predominantly garish looks and "bling" factor.
Now WRT to using car speakers, like coaxes and triax's, this is rarely a good idea. The (vast) majority are meant to be listened to at significant off axis (like door mount) angles or even reflected (such as rear deck mount). Thus the upper frequencies tend to be designed significantly boosted to compensate (most, not all). Listened to on axis (like with HT), they will be very bright.
...but, the EQ of typical HT AVR "room correction/calibration, etc" may attenuate this enough to make it bearable. I think.

cheers,

AJ

Gene Kranz: I don't care about what anything was DESIGNED to do, I care about what it CAN do.

I'm not the least bit unaware of that. IMO autosound drivers with specs that are suitable for a home would be compromises as far as using them in a car. The two environments are too dissimilar for a one-size fits all solution.

You can drive a screw with a hammer if you want to; a screwdriver works better. A driver specifically designed for auto use will have quite different specs than one designed for the home. It's certainly not a matter of color and frills or lack of same that differentiates the two genres. That doesn't mean it can't work in the home, just that it won't work as well as one that is designed for the home. The same applies when the shoe is on the other foot.

They are designed for very different environments... I love car analogies, so here we go. A Ferrari Fiorano and the Swamp Rat will get you to wherever you want to go on the street, but when you hit the Nuremburgring , which one would you choose to get the job done? Now, lets say you want to go slogging through the bayou after a hurricane... different choice, right?

All things being equal in theory, they both get the job done. Home audio speakers are designed to be strong, but light and fast enough to articulate the microdetails found within the recording. Car audio trys to bring these qualities as well, but compromises must be made due to the harsh conditions created by shock, vibration, heat, moisture and extreme cold. We cannoy forget the occasional Starbucks.

Ther different conditions that speakers are designed for call for different materials, construction techniques and crossover designs. When I worked at Magnepan(summer job before the Corps) they were working on planar magnetic drivers for car audio. 10 years and god only knows how much time spent, they still had not made one that worked for the masses. My point is that some technologies simply cannot make the leap frm the home to the car and visa versa. Just because the theory of operation is the same for conical drivers does not mean that all driverswill work or are desireable for a given task.

This makes sense.