hooking car sub to home theatre sub amp

[[DANGERDAN]]

My settings were all correct as i have a pretty good understanding on how the system all works, the bass boost was off and the gain on about 85% with the headunit sub level set to 8+ and the crossover set at 85hz with a 24db drop with every octave. The sub enclosure is around 1ft square (not ported for better accuracy) and hooked up only to one of the two alpine type r 12's due to it not having any where near the sufficient power for both. (wired in 2ohm for 100% power output from amp).

The new kicker with the same settings does well in accuracy its just not powerfull enough, distorts way too early for claimed 500 watts.

[STEvil]

Do you have the sub facing a loading wall, or is it open to the room?

[[DANGERDAN]]

iv had it in the back seat facing backwards forwards upwards in the boot same thing outside lol, it was def just the alpine being not a great amp. It was a mrp which im sure is the budget end of alpine so im not concerned or put off with buying another alpine.
As said before the kicker resolved the bad accuracy the alpine presented i just don't think its powerfull enough due to distinct distortion in large excursion situations.

[Bun-Bun]

That's just the thing. Alpine amps are good products and I have never heard anyone else make such a claim as you are here.

Though your statement of sealed enclosures being more accurate tells me you do not understand sub box design.

Only powering one sub? They are in separate enclosures?

[STEvil]

Alpine amps work. I wouldnt call them good products though.

Sealed enclosures do have better control characteristics than ported boxes for the most part, but usually car audio subs have overbuilt suspension so they tend to work best in unsealed (ported) enclosures.

What are the settings on your receiver/amplifier? If it also has a crossover the settings may be "multiplying" the crossover points.

[[DANGERDAN]]

Yea i have played with ported and sealed enclosures and i always seem to come back to sealed due to better control and accuracy that it produces, the only thing ported offers in advantage to me was a deeper frequency if ported right but that counter acts itself when the frequency response becomes less accurate and i love to hear crisp bass instead of the boom boom that most spastics like to feel more than hear.
What i have atm so that there is no cross filtering between the amp and the headunit is the unit controlling the LPF @ 85hz with a 24db per octave slope and then the power amp is on 200hz and from what i would say would not interfier at all due to the HUnits filter cutting most of the sound out at that frequency.
I did this with the alpine just to insure multiple filtering was not happening and i also tried with the unit filter off and using only the amp as the filter etc so i am pretty conscious about the cross filtering anyway hehe :P.

[Bun-Bun]

Of course there are better amps then alpine. But they are good enough and i definitely have never heard of any exhibiting the issues presented here.

Enclosure design is far more complex then the generalization's made here. Sealed have the benefit of being cheaper (easier) to design and build. As well are smaller and more predictable in there environment.

I find 12db per octave to behave a bit more naturally with my setup. But other than that i can only think there was something wrong with that amp.

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[[DANGERDAN]]

Yea there probably and could have been something wrong with the alpine but its not my concern right now, as for the enclosure you have to agree that you cant beat a sealed sub in terms of accuracy and quality but a ported sub has the benefit to go louder, use less power and hit harder at lower frequency's. I am a quality man i care not for loud and boom boom, i want to hear the bass guitars, the kick drum, the snare and any sub sounds without the distortion of just 50hz smashing away.

[STEvil]

I tend to rely on my tower speakers to cover the majority of the audible output, though I tend to build over-sized towers. Subs really should only be felt in my opinion, but that doesnt mean you cant use them to reinforce the ouput from the towers if you have to.

that said, I dont think sealed with the type r's is the best choice, at least not in a home. A 4th order or horn might go better if you wanted to stay sealed on one side though.

[Bun-Bun]

The alpines definitely would prefer a vented enclosure.

Vented enclosures are just as capable of sealed at reproducing accurate sound. It just takes a properly designed enclosure and driver.

I agree with stevil, I take my fronts down as low as possible. The highest i like to crossover is 60hz.

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[[DANGERDAN]]

No matter what, a sealed sub will always have a flatter response on the frequency spectrum and that's if the speaker was designed well in the first place, so no the alpine "IMO" would not be better off ported at least not for me. It is a personal preference, sound quality wise sealed is the way to go but a ported box can have near quality to that of a sealed but the sealed enclosure is better if you are after the flattest response possible in a speaker enclosure. If i did port however i would get more efficiency and less power requirement but that's something il just sacrifice.

Yea i think your right with the crossover at 60 or below but atm i have crappy speakers that cannot handle that part of the frequency too well so that's why its on 85 so that middle area is not left with a whole.

[Bun-Bun]

Vented enclosures have just as flat of frequency response as sealed in their designed range (that is tuning frequency up to ~50-60Hz). The only thing you are going to get better out of a sealed enclosure is transient response. And if you are concerned about accuracy to that extent then you need something a lot better than alpine/kicker drivers/amps.

[[DANGERDAN]]

That's exactly right, you may be able to get a close similarity in frequency response but the difference is in the quality of that, sloppy bass vs tight bass and that's what is sacrificed when going ported.
What other subs would you know of that are commercially known that offers higher quality output for subwoofers. ?

[Bun-Bun]

for car's or home audio?

for car's there is memphis audio, dd audio, RE audio...

car amps memphis audio, audison, sundown...

will have to check a car audio forum. I haven't kept up and design primarily vented enclosure's.

Home audio see rythmik subs...

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[STEvil]

I dont agree with you that sealed enclosures provide tighter bass. That is a function of the design of the sub, design of the enclosure, and the settings of the amplifier(s).

Sealed enclosures are ok for what they do but I have never heard one in a system that I would rely on as the sole source of ouput. That said, there are improvements that could be made to most ported style enclosures as well, rather than just a round or square tuned port.

Here's a few more that are better than Alpine:

Eclipse, Fi Audio, DC Audio, EarthQuake, MA Audio, Kicker, Rockford, MTX, Lanzar.....

Pretty much any mid-top range manufacturer can beat Alpine, other than Sony, Dual, and Pioneer maybe

[Bun-Bun]

Alpine electronics I have always found to be one of the best. I have a Alpine HU from a few years ago and its awesome. Their speakers have gone to crap though. I had some Type-R 6x9's that sounded pretty good but kept blowing tweeters. And now their build quality has gotten even worse. Type X subs are a joke. Never had a problem with any of my Memphis Audio stuff.

JL Audio W6v2 and W7 subs are good. But you will pay for them. Phoenix Gold maybe...

I dont agree with you that sealed enclosures provide tighter bass. That is a function of the design of the sub, design of the enclosure, and the settings of the amplifier(s).

This. I have a vented enclosure. Port tuned to 32Hz. four 10" Memphis PR subs powered by a 1100wrms Memphis monoblock. Incredibly tight and fast bass. Songs with strong drum presence you feel as if the drummer is in the car with you. However you cross it at anything higher then 55Hz and it sounds like garbage. But I also designed and built the box myself for my specific drivers. Not some cheap pre fab box.

[[DANGERDAN]]

Yea well i think there are multiple reasons why you need to use 55hz for sound to come out crisp and clear, one would be that your using 12db slope which means that it takes longer for the actual cutoff to occur in the frequency band and means that your sub try's to distribute sounds a lot higher and possibly muffles the sound. If you use 24db you could decrease the distortion and make it possible to go higher in the crossover.
There's also damping factor which i reckon affects bass performance if you try to mix the entire sub frequency's with each other and causes interference because of that, thus explaining why you cant use anything higher than 55hz because sound is affected when the cone try's to compensate for alternating polarity at high sub hz and then having the kick drum in the middle of it and then because of low damping the cone cannot get back into place quick enough to not affect the sound.
Or you could be one of those boom boom people i was talking about xD.

My two cents

[STEvil]

Dampening factor will only change a ported box below tuning. Above tuning frequency ported enclosures operate nearly identically to sealed. Good old helmholtz..

That said, 55hz at 12db per octave isnt much different than 85hz at 24db per octave.



edit - crappy graph, I know, but it illustrates the point that 85hz/24db is taking you away from the near midbass frequencies of a kick drum faster than the 55hz/12db slope is.

[[DANGERDAN]]

wasn't referring to damping factor with sealed vs ported enclosures, just in general towards crossovers. Yea i was talking to someone today about how the ported enclosures affect only the frequency's below the tuned frequency.
Nice graph that actually shows some good information about the slope and i see where your coming from in that aspect.

[[DANGERDAN]]

Do they have like a dynamic slope where you can have it drop off 12db and then say at 150hz make it drop off higher like 24+db.

[Bun-Bun]

Many factors come into play above 55Hz. Standing waves, resonate freq. of box and car, port distortion, the fact there is a gas tank between the sub box and the cab... etc...

And that graph illustrates perfectly what I was experiencing earlier today when I was playing around with my settings. I was using my HU's active crossover but found I could fine tune it enough. Turned off the HU crossover and adjusted at the amps. Got it perfect now. But I did do some comparisons of 12db and 24db slopes and the 24db settings left the bass feeling lifeless.

[STEvil]

Do they have like a dynamic slope where you can have it drop off 12db and then say at 150hz make it drop off higher like 24+db.

If you did it digitally (software) there is no reason it couldnt be done. Probably can do it through analogue as well but then you're going to build a custom one of these to do it right:

[NEOAethyr]

I may be a bit late since the topic has progressed, but I just stumbled apon this vid and I thought about this thread, interesting info I think.
With a dmm you could wire a whole array with parallel and series and figure out the ohms without alot of tricky and questionable math.

[STEvil]

tricky and questionable? uh... no.

[[DANGERDAN]]

yea id seen this a long time ago lol, the guy put me off so much the way he was presenting his information. I actually couldn't trust what he said.