sealed, vented or both??

[zerox61]

hey. i heard people say that sealed subwoofer enclosures will reproduce a more accurate bass and ported will reproduce more deeper bass and louder. i want both =). so would it be good to have 2 subwoofers, one sealed and one vented in one system? right now i have both subwoofers , both 10" hooked up. im thinking of doing the same thing for my car. but except with better amp, sub and equipment. or should i just stick with one type of sub woofer instead of both.

 

[mike c]

one type for both is better.

a properly designed ported subwoofer should be accurate. if it wasn't it's because it wasn't designed properly.

you WILL encounter sealed subwoofers that isn't accurate as well. so it's not really in the type of enclosure, but how well the driver, amp and enclosure is designed.

what subs are you looking at?

 

[annunaki]

Mike is correct here. A properly designed ported system can be every bit as accurate as a sealed system (to the ear) if designed correctly. A poorly designed sealed system can sound worse than a ported design or vice versa.

Each woofer is usually going to have atendancy towards sealed or ported. Knowing the driver in question along with its specifications will yield where its tendancies lie.

 

[zerox61]

oh ok. i see.looks like i stilll got much to learn. u got any sources with tuning ported woofers? i use this program called WIN ISD. http://www.linearteam.dk/default.aspx?pageid=winisd

and i was wondering. if a box was tuned too low. people said the sub can be damaged. how does that work?

 

[mike c]

annunaki is our resident experty DIY'er. show him/us what driver and amp you are planning to use ... he/we can probably recommend the proper enclosure type/tuning for you.

or at least, give us your budget, and what you want to achieve.

 

[zerox61]

annunaki is our resident experty DIY'er. show him/us what driver and amp you are planning to use ... he/we can probably recommend the proper enclosure type/tuning for you.

or at least, give us your budget, and what you want to achieve.

my budget is arround 500$ AU.. which translates about.. 350$ US?? im guessing. at first im going to use if for my computer. and when i get my licence i will install it into my car (alfa 156 XD) so after building it its gonna be for my computer. so a realitivly small room. but i rekon the difference between my small room and the car.. shouldnt alter the sound quality a big difference.? room size difference is about stacking 7 or 8 of the alfa to have the same approx volume.

but i rekon with the budget i might re consider the Logitech Z5500 (about 700$ but i can get for about 500$[told u stuff here is rip off]) instead of a DIY. since i owned those speakers for about one year. i might get them back. but im looking for a more 'fun' kinda thing like building it myself.

amps maybe i will build one too since im into eletronics.

considering this one:
http://h1.ripway.com/haiiz/IMG_0759.jpg
i it does not say what power input it uses on the page so i will have to ask the store. by "transformer" i think its to the house but i think a bit of mod can make it use direct from the car with no dc-ac inverter.

and the signal to noise ratio.. 122db..but unweighted. what does unweighted mean?

or this one looks pretty good to me. in terms of specs.
http://h1.ripway.com/haiiz/IMG_0743.jpg

please help me pimp my speakers! haha thanks.

 

[mike c]

i'm no expert (as in, i'm pulling things out of my $%^) but i think DIY'ers tune subwoofers higher in cars because of the massive cabin gain.

if you tuned something for your room, there'd be too much low end for the car ... if you tuned something for the car, there'd be NO low end for the room. DIY'ers is this correct?

sealed maybe?

 

[zerox61]

hey. yeah i wasnt too sure. if the size difference would affect it i thought the difference was in size on my room and car would be too small to have changes. i havnt actually tried this. got no time but thats only my theory.. but how does it actaully affect it? like resonance? or what?

 

[mike c]

i think by frequency response ...

anyway, since most PC subwoofers are tuned to the high 30's anyway ... it's a safer bet to tune for the car which is around 30hz as well ... all this is talking about a ported subwoofer.

 

[zerox61]

hey. when searching for a sub. we find one that is same as the rated power of the amp in rms? or do we pick one that has higher power rating than the amp.? but then people will say thats called underpowering..

 

[annunaki]

i'm no expert (as in, i'm pulling things out of my $%^) but i think DIY'ers tune subwoofers higher in cars because of the massive cabin gain.

if you tuned something for your room, there'd be too much low end for the car ... if you tuned something for the car, there'd be NO low end for the room. DIY'ers is this correct?

sealed maybe?

I tune low for car or home. If you tune too high without a good infrasonic filter say good bye to the subs.

Most people want extremely high output in the car so I see no issue with tuning into the 20hz range if the woofer will allow.

I was modeling the JL Audio 13W1v2-4 last night and it does extremely well (for the house) tuned to 21hz. The issue is that it has a rather large enclosure 5.3 cu.ft. or so. They go for about $159.00 US.00 They also do great in a sealed enclosure of 2.25 cu.ft.

You could simply build two enclosures, one for the car and one for the house for any sub if you wish as well.

 

[annunaki]

Matching the rms power output from the amp to the sub's rms power handling is a good idea for most users. Having a bit more power than the sub's rms is not a bad thing either.

 

[zerox61]

Matching the rms power output from the amp to the sub's rms power handling is a good idea for most users. Having a bit more power than the sub's rms is not a bad thing either.

how about the sub's rms is higher then the amp's? would that be called underpowering?

 

[annunaki]

To some degree but it will not destroy your woofer. Underpowering is fine as long as you know where the amplifier goes into clipping. When an amplifier fully clips it doubles its rms output capability at .1% thd. As long as you keep the amplifier from clipping you will have no issues. This is typically why we see limiting circuits built into plate amplifiers.

Example:

If an amplifier is capable of 100 watts rms at .1% thd, it will output 200 watts when fully clipped. Now the power isn't really useable as it will sound terrible, but it still is double the power.

The issue that you run into is a if a sub is rated at 125 watts rms and the amp is 100 watts rms @ .1% thd and a person listens with the amplifier partially clipped outputting 150 watts rms the sub will burn up if given enough time.

Too much power over time is what destroys speakers.

Distortion alone cannot destroy a speaker, especially a sub. A 10 watt fully distorted signal played into a subwoofer would be no problem for the sub. Neither would a fully distorted signal at the subs rms power capability. It would simply sound really bad.

If under powering alone destroyed speakers, everytime one turned down the volume and the amplifier outputted 1 watt or so the speakers would be damaged. It does not make sense.

Ideally, for the average user, keep the rms output of the amplifier as close to the rms input of the speaker. For more advanced users after more dynamic capability, it is common to have much more rms power on tap than the speaker is rated for.

Also see my post #17 here: http://forums.audioholics.com/forums/showthread.php?t=36834&page=2

 

[zerox61]

thanks alot. for clearing up the confusion i had earier during the post of that other thread about the 20watt amp. helped alot. i wont be on the forums much anymore because of exams. i will be back in about 3 weeks when its finally over. then no more school! yay.