Difference between Car sub and home theater sub (1 Viewer)

[dhutchings]

Hello All.

Let me List my Setup specs:

Pioneer 7 band Graphic EQ(this thing is my best friend...it makes a detrimental difference in the quality of my sound....the lows super way overpower the highs and mids without this.)

Yamaha 5.1 (im not sure the model...i dont feel like getting up to look at it either) 550 Watts in 2 ch mode..

2x Radioshack 10 inch cone version PA speakers 160 watts Peak Connected to the Yamaha reciever

Out from Yamaha to
Kenwood 7.1 Powering no speakers. Just using Active sub out to another stereo.

Insignia 2ch 200w stereo

2x Kicker 12 comp series 300 watt subs.

As you all can see i have a complicated setup. Its a little hard to explain. Sorry if the way i wrote that is weird. Believe it or not it sounds...At least to me really nice.


I have an honest question to ask. Please don't flame me with things like car subs are bad don't ever buy one...or home theater subs are bad....Thats not what I am asking for. What i am asking for is this:

Why do Home Theater Subs Project(correct word?) better than Car subs? Its not like it matters in my room. But say i took them downstairs in a basement, (which i did) mt basement is 2 1/5 times bigger than my room(i have a small house and room)why are they not heard as well. I would expect since they are so powerful in my room, that they would be at least heard downstairs. Now if i take my old 100 watt home theater sub i can hear that much better than the car subs at 600 watts.( i have 2 of them.) In my room the subs get loud to to the point that my windows start shaking. I am not trying to brag or sound like an idiot or something else of that nature, i am being honest.


Again Sorry if this is not written very well.

Thanks for the help.
Dhutchings

 

[Robert_J]

You have to look at the two parts that make up a "sub" - the driver and the enclosure.

Drivers - The biggest difference is marketing. That's right, the majority of the time a "car audio" driver will work in a home setting. The reverse also works most of the time as well. I run 15" web.archive.org/web/20070209015758/http://www.tcsounds.com/tc3000.htm TC 3000's in my home theater. They were originally designed for the car audio market. Years ago, Adire Audio introduced the 12" Shiva driver as one of the first high excursion subs on the market. It was first marketed to the home audio crowd but the car guys started buying them like crazy. The car audio market is much larger than the home market and it is really the only way a driver company will sell enough to stay in business.

Enclosures - This is where the difference in performance comes into play and it is all explained by Hoffman's Iron Law (Google is your friend). To sum it up, large enclosures produce deep bass. The smaller the enclosure, the more difficult it will be to produce bass. You will have to have a very high excursion driver, add lots of EQ and pour on the power.

In your case, your room adds gain just like the inside of a car. The larger the room, the less natural low end boost. I'll also bet that your home theater sub is in a larger enclosure and it is ported. Ported enclosures that are tuned low, also produce more low bass than

 

[dhutchings]

Thanks for the reply. My subs are car subs. They are not in a ported enclosure. I actually had to put boom tape inside the enclosures because of all the air leakage. I will definitely look up Hoffman's iron law on google.

 

[Robert_J]

This is my favorite Hoffman definition. Other links on Google get into a lot of discussion. http://ldsg.snippets.org/appdx-a.php#HOFFMAN

I didn't get into much about Theile/Small parameters but that is the determining factor on most sub installations. Marketing folks are pretty good about selling to their correct audience. Kicker, since you own them, is great at it. Their subs are loud and can take a lot of abuse. But as you can see, take them out of the car and they will not perform very well. If you look at the T/S parameters, they will typically have an Fs of 30 to 35 hz, a Qts of .5 or higher and a very small Vas. Compare that to the parameters of my TC-3000. The Fs is 22 hz. That's almost 1/2 octave lower than most Kicker subs. The Qts is also .308. When installed in a sealed box, my sub has a more shallow roll-off in the low bass region of the frequency spectrum. The only thing our subs have in common is a low Vas. The only drawback on my sub is the high inductance. That does impact the sound quality some but not much. The inductance induced hump in the frequency response was EQed out within 2 days of building my subs.

Get out of the mainstream subs and look at ones from smaller companies. I helped another guy recently with subs from Exodus Audio. TC Sounds / Audiopulse is great but expensive. AE Speakers. Fi Car Audio. Elemental Designs. At all of these places you can call them and sometimes talk to the owner/engineer. You don't get that at the larger companies.

 

[dhutchings]

Sorry that took me so long to respond. My internet connection went down for a while. The main reason i bought the kicker subs is because the store that was selling them was selling them 50 bucks a piece. 100 bucks normally, but they were having a going out of buisness sale. At the moment i do not have enough money to go out and buy new subs, so thats out of the option. I used to have an ED sub. (elemental designs) That was a nice sub for 10' sub. That was a pretty loud one. I am going to stick with my kickers though because they are loud enough for me. The loudness of the bass sometimes cuts out the rest of everything else if i turn the amp up that they are connected to past 60%. I know this gonna be like a "noob" question but thats what these places are for. What does QTS and VAS mean? There probably something i might know and feel stupid for asking what they mean, but then again i could be wrong with that theory. I am guessing fs means Frequency response or something close to that just from the context.

 

[Robert_J]

Originally Posted by dhutchings

I am going to stick with my kickers though because they are loud enough for me. The loudness of the bass sometimes cuts out the rest of everything else if i turn the amp up that they are connected to past 60%.

Loud does not always equal accurate. My TC-3000's were extremely "loud" when I first built them but they had absolutely no low bass. They had a huge peak in the frequency response at 55 hz caused by the inductance of the voice coil. I used a parametric EQ (Behringer Feedback Destroyer) to flatten that peak and boost the low end a little. Now my subs are flat from 80hz to 17hz with usable bass below 15hz. A 15hz tone will cause the cones to move and I can feel the pressure waves in my chest but I can't hear anything.

Also, if your sub is overpowering your other speakers then your system is not properly calibrated. Your sub should never call attention to itself. Even when watching an action movie the explosions should just envelop you and not come from your sub. Really you shouldn't listen to your system, it should be part of the movie experience.

This should answer your Qts and Vas question - http://www.eminence.com/resources/data.asp
Click the Know How section - http://www.audiopulse.com/
More information - http://www.diysubwoofers.org/