hardware and subwoofer placement

[Shieldwolf]

I'm putting in the hardware today. Mounting the mother board etc. I was wondering where most people mounted there hardware. I'm planning putting a Klipsch subwoofer in the cab and I wan to be sure it won't screw up my cabinet.


Comments or suggestions

[ashardin]

Well. the main problem with the sub inside the cab are rattles and muffled sound.  It will happen, especially if you have refurbed an old cabinet.

Also, i'm sure the sub is shielded if its a mulitmedia sub, if its not, don't get it close to the computer.  Magnets + HD's = bad).  If your computer if inside the cab you also run into the long term effects of the bass waves (vibrations) doing potentially bad things to your computer.

The second problem is you will lose a good deal of the sound.  It will have to penetrate the wood, coin door, or any other opening.

I have tried subs inside and out and I think you will be much happier placing the sub outside the cab.  You could put it on the side or even behind if you are worried about it showing.

If you are going to put the sub in the cab I think you are just as well to skip it entirely.

[JackTucky]

Subwoofers emit low frequency sounds, that travel well through walls, floors, etc.  Did you ever live near someone with a loud stereo, the only sound you hear is the bass?

I have my sub in the cab, it sounds awesome.  In fact, the cab sort of extends the subwoofer.

In my home theater, my DD 5.1 sub is in a cabinet.  Sounds great too.

BTW, I could be wrong, officially, but what I have sounds good to me.  

Art

[Santoro]

I screwed my square sub directly to the wall and floor inside my cab using L-Brackets.  I also put felt between so that there would be no vibrations.  

Looks and sounds great.

[ashardin]

If you guys like the sound, no problems with it.

I'm a sound nut myself (big car system, Home Theatre, etc.)  While it is correct the low frequencies do go through walls etc. much better than higher frequencies, you are losing a great deal of the sound to absorbtion (that's why the person's music next door is muffled and not as loud when they have a sub kicking).

So, especially with your HT sub in the cabinet, you are losing a great deal of the sound waves and volume.  Just for kicks, take your 5.1 sub out of that cabinet and hear how much better it sounds.

Again, though, I'm a sound nerd (not audiophile though, my ear can't tell small differences), so if what you have makes you happy, by all means stick with it.

[slycrel]

  Question on that...  most subs have some sort of tube into them.  Could you cut a hole in the front of the cab (near the coin door or something) and line that up?  Wouldn't that be much closer to the same?  Or even build the guts of a sub into a box that's part of the outside of the cab itself?  So that you've got three sides to the box in the cab and the other three being the bottom of the cab and two outside walls...  know what I mean?

[bluGill]

Speaker cabinet design is a science that isn't fully understood.   If you want to know, get a book on the topic and learn what works and why.

Holes in the right spot are good things.  Holes in the wrong spot are not.   Speaker cabinets or some shapes are better than others.  In an upright cabinet you have plenty of room for a sub in the base, but you might need to move the computer to the top or something.  

[ashardin]

slycrel

Yes, you can extend the port through the front of the cab, its done all of the time in car audio.  They port the subs in the trunk through the rear deck lid into the cabin of the vehicle.  But (and there is always a but), as BluGill said, speaker building is a science.  You cannot arbitrarily extend the port length of a subwoofer without negatively affecting the sound quality.  The "hole" is much more than that, it is a mathematically calculated size and length the maximize the speaker's sound.  

Now, your second idea is very doable.  I've got a picture of it from one of my cabs.  2 6 1/2" shielded subs (so as to not affect the HD) on the front, and then I build a sealed enclosure behind it in the cabinet according to the T/S parameters of the speakers.  Many raw drivers will come with an info sheet with the optimum sealed enclosure size, measure it and build it out.  www.partsexpress.com is great with the info they have on the speakers, including online info so you can get the driver that works great for your application.

here is how it looks mounted (you cannot see the enclosure in this pic though.

[HeadRusch]

Guys, its a MAME Cab...not a $40,000 dedicated home theatre.

Mines inside my cab....seems to work fine.  Had it outside the cab for awhile and didn't notice
tremendous difference considering the MATERIAL I was playing

[AlanS17]

The best position for a sub in a machine would be at the bottom in a corner and make sure that the port (the hole) and the speaker itself face inward and not against the wall. This should maximize sound while minimizing rattling.

In addition, even though most computer speaker sets are shielded, this doesn't always to the bass because it's made to be set to the side away from everything else.

So I would recommend some of those sliding adjustable mounts that you can buy from Happ Controls (or Bob Roberts) and install the board along the inner wall as far from the sub as possible. If you plan on using a full PC with case then just set it in there in the bottom as far from the sub as possible.

[slycrel]

  Thanks for the reply guys.

  Ashardin, thanks for the picture!  I've been considering if I wanted to try something like this option or not, I'm glad someone got it to work!  I have an older sub that I want to put into this project and was wondering about how to do it.  I'll let you know if I have any more questions.  

  As for the $40,000 comment...  some of us are audiophiles.  I'm pretty picky about that kind of stuff, so I don't want to feel like I did a sub-par job on my cab.  Oh, and my $ limit is $500, which should be more than enough for building from scratch like I'm doing.  Besides, I'm going to be using it for more than pac-man era games.  

[grafixmonkey]

While you do hear the bass through walls more easily than the rest of the sound, it doesn't mean it passes right through...  The frequency cutoff for a sub is usually in the hundreds of Hz, sometimes as low as 120Hz like the Klipsch systems, sometimes as high as 250Hz or more for systems where the sub has to make up for the satellites having really tiny speakers.  I'd guess that when your neighbor plays the stereo loud, you probably don't hear much of anything above 70-80Hz or so.  (unless they've got it really pumped up.)

Besides, most arcade systems don't have all that great of a speaker system, just a couple decent cone speakers under the marquee.  The positions of your speakers are more important than the other factors.  Have a friend hold a couple of speakers in various positions in front of you while you stand and listen, and see what position sounds good.  Personally I like them above and in front, so they make an equilateral triangle with my head.  Wider expands the sound towards having a "stereo hole", and closer contracts it until it becomes mono.  Driving games made a cool audio effect by putting the speakers right behind your head, in the top of the seat.  Depending what your panel and cab look like, you could even put them behind the machine facing the wall so they reflect the sound off it and to your ears.  Also, a subwoofer feels most powerful right in front of its bass reflex tube (that's the tube you mentioned Slycrel).  If that is close to you while you play, you'll feel the vibrations more.  You also might not have to turn the bass up as high, so you'll bug the rest of your house less while you play.

[slycrel]

  I didn't mean to give the impression that I'll only have the sound at the bottom.  I'm thinking of putting the subwoofer at the bottm with 2 sattelite speakers in the marquee like most arcade games do.  I'l let you guys know how it works out.  Probbaly whether oyu like it or not.  

[jdsony]

This seems to be a subject that comes up a fair bit. Some people will be happy with any sounds they get out of their setup while others will only be happy if they have achieved perfection. I myself am one of the latter but understand that some people really don't hear the difference between decent and amazing or some just don't care.

If you extend the port on your subwoofer you are essentially changing the frequency the sub will produce. This may or may not be a big issue with how the sub sounds. Also if your sub isn't completely enclosed (the speaker isn't completely enclosed by the box) and it has a port then ideally you would want both the sub speaker and the port facing out of the box. All these things depend on lot's of factors though and chances are if you just put the sub in the enclosed cabinet you will be happy.

The easiest route would be to use a sub with no port and have it coming out of the cabinet. Non-ported subs generally produce less bass than if they were ported but the bass is tighter and cleaner sounding.

[grafixmonkey]

"port"?  you talking about the bass reflex tube?  I'm pretty sure the only thing extending that a few inches would do is slightly change the resonance characteristic of the sub.  (slightly, meaning you might be able to measure it with an oscilloscope and some software...)  From what I've seen it looks like the tube is designed to provide a way for the air to escape when the speaker moves in towards the box, while not allowing any particular note to resonate more than the others, and not delivering the sound waves significantly out of phase with the ones coming directly out (so they don't cancel.)

So don't stick a long piece of PVC pipe or a vacuum hose on it or anything, but don't worry about putting the reflex tube next to a hole in the cab, extending it a few inches won't change anything.

and about satellite positions - the vertical placement does not change the sound as much as the horizontal distance between the speakers does.  Try the test I mentioned, you might be surprised how it sounds.  Or if you don't feel like it, just go for the equilateral triangle thing because that's what sounds best to most people.

This place is divided between the people who enjoy accurate reproduction, and the people who want to build badass monster gaming machines...  really, the games Mame plays didn't have sound systems nearly as good as a decent set of PC speakers with sub, and sound fine on most any speakers.  They didn't even produce sound that was worthy of a high quality system (8-bit, 11khz samples or lower).  But, man is it nice to feel the bass shaking too!  (esp. playing mortal kombat!)