downfiring drivers vs. sidefiring drivers

ronaldo141

does anyone know the benefits of downfiring drivers vs. sidefiring drivers if there are any and which is the best to have? thanks.

goingganzo

i think the differance is between them is if you do a down flirting sub and you can put a plate to help out sertan frencies. but if you have a carpeted room you will lose some bass. also the sub has to have to be able to be down flirting it has to have a small % of vc sag. if it has to much you will dammage the woofer over time. but i have allways had front flerting subs. or back in the case of my car lol

Tour2ma

WhaDsay?

scottvamp

Flirting subs??
My PSW1200 has a downfiring port and side firing speakers. The port fires into its own base. Power port tech.
In my livingroom setup I have a AR 12" that is downfiring and once again it is firing down on a wooden base that is part of the sub itself. It has about a 2.5 inch gap and the port is also downfiring. For a about $300 it has done nothing but impress me from day one.
A miss perseption perhaps with down firing subs is that the subwoofers fire directly into the floor. Whatever surface you put it on. In most cases would be carpet. (not good) I have only seen very cheap subs built like this - like a ratshack special for example.
Inwhich I owned in one of my first setups and it sounded aweful.

MxStYlEpOlKmAn

Have u thought of putting them on a raised platform? My mom has a altec lansing computer sub, downfiring. It use to be my friend's and his was on carpet and it sucked eggs. I traded my computer speakers off with him and gave them to my mom. It is now on a platform on the desk and I swear it rocks the house. night and day

kberg

Ok, so my Infinity BU2 is downfiring on carpet w/o a platform. Are you guys saying that I should raise it off the carpet and have it downfire on a hard surface, or raise it but still have it downfire on the carpet? If so, any suggestions for what might be most effective?

Doc?

Thanks

MxStYlEpOlKmAn

Well obviously if you put it on a hard surface...right below the sub - there will be no difference. Put some feet on the sub and put it on a surface...but try it first to see if u find ne results...

goingganzo

just get a large piece of slate put it under the sub this will help you out.

Tour2ma

I can kick in a bit with some confidence here (I passed a test… inside joke).

Originally posted by MxStYlEpOlKmAn
My mom has a altec lansing computer sub, downfiring. It use to be my friend's and his was on carpet and it sucked eggs. I traded my computer speakers off with him and gave them to my mom. It is now on a platform on the desk and I swear it rocks the house. night and day

Sid, computer sub’s are a whole different thing. What’s it reach down to… maybe 60Hz? But it’s not how “low it goes”, it’s how high it rises that explains your example. It almost certainly is reaching up to 250Hz, well into mid-bass, and carpet will kill mid-bass. Trading carpet for a “sounding board”, i.e., the platform and desk, will make a dramatic difference in the mid-bass.

Originally posted by kberg
Ok, so my Infinity BU2 is downfiring on carpet w/o a platform. Are you guys saying that I should raise it off the carpet and have it downfire on a hard surface, or raise it but still have it downfire on the carpet? If so, any suggestions for what might be most effective?

First kberg, at what frequency is your crossover set? If it’s over 120Hz – bad, 120Hz good, 90Hz better. Somewhere in the 90 to 120 range, where true, deep bass starts, fear of a sub’s output being muffled by carpet ceases to be a real issue for a down firing. True, deep bass is difficult to get rid of, that's why it's the principle realm of the standing wave. A number of company's make a pretty good living at offering solutions to standing wave issue (tube trap for one) because carpet, drapes, etc., just don’t phase true bass.

Ronaldo,
As for down vs. front? It's just the first design decision. Equal performers can be found using both designs. With true bass dispersion is not an issue so you don’t need the spread often touted for downfires. Absorption not an issue so you don’t need the direct-line touted by frontfires. Once your ears and gut are satisfied, it can come down to cost-value and eye appeal. For some that means front because they want to see that driver working (it can be appealing).

ronaldo141

thanks for your help tour2ma. I've also seen some interesting older velodyne subs with both down and sidefiring drivers, but evidently it doesn't make a big difference.

kberg

Originally posted by Tour2ma


First kberg, at what frequency is your crossover set? If it’s over 120Hz – bad, 120Hz good, 90Hz better. Somewhere in the 90 to 120 range, where true, deep bass starts, fear of a sub’s output being muffled by carpet ceases to be a real issue for a down firing. True, deep bass is difficult to get rid of, that's why it's the principle realm of the standing wave. A number of company's make a pretty good living at offering solutions to standing wave issue (tube trap for one) because carpet, drapes, etc., just don’t phase true bass.

My crossover is set at 80Hz, so it seems like I'm Ok on that issue.

MxStYlEpOlKmAn

Tour, So your saying putting Bose 'Bass Modules' on a raised platform will help the bass? Considering they play about 25% or more of the Bose Cube's Midrange...haha

Tour2ma

kberg,
At 80 Hz you should be fine from a loss consideration, but another problem that Doc alerted me to, could become a factor. Depending on the bass attenuation rate of your processor you could face wave convergence due to multiple bass sources. Even with a 12 db per octave roll-off, your mains are still reproducing a fair amount of bass “information” for a ways below 80 Hz. Ditto for your sub above 80.

Multiple bass sources can interact directly with each other as well as all of their reflections, creating bass “hot” (reinforcement) and “cold” (cancellation) spots in you listening room. If you play test signals under 100Hz at 80 db or less, a walk around your room, with or without a SPL meter, should let you know whether this is occurring. If it is, raise your crossover point to 90 and repeat.

Sid,
Hadn’t looked at “bose” in awhile, but seem to remember they’re front ported, so they’re not firing into the carpet at least. Can’t say if raising will help for sure, but if they firing into a sofa or chair, yes it’ll help prevent the killing of the frequencies over 120 Hz they handle. And as with any speaker that reproduces bass, corners will reinforce bass, away from walls will lean it out.

I tried to help a friend a while back that went bose. Corner reinforced the base, but they just sounded so “boomie”, any benefit of sounding deeper was lost.

kberg

Originally posted by Tour2ma
kberg,

Multiple bass sources can interact directly with each other as well as all of their reflections, creating bass “hot” (reinforcement) and “cold” (cancellation) spots in you listening room. If you play test signals under 100Hz at 80 db or less, a walk around your room, with or without a SPL meter, should let you know whether this is occurring. If it is, raise your crossover point to 90 and repeat.

You mean set the crossover at the sub at 90Hz, if needed, yes? When I said I had my crossover set to 80Hz, I meant at the receiver. Currently, the setting at my sub is all the way clockwise to 200Hz, per Doc's recommendation to prevent double filtering. So, with that said, what recommendation(s) do you have?

kberg

Originally posted by goingganzo
just get a large piece of slate put it under the sub this will help you out.

Would doing this yield a tighter bass response from my sub? Is that the idea?

Tour2ma

kberg,

Only recommendation I was making was to check your room to see if you have a problem. If you’ve been living a while with your rig set as you described, it’s not likely that you do. But if you listen in the same spot all the time, it’s possible that the bass in other listening positions in the room is “unnatural”. It doesn’t hurt to check.

Should you find an issue, any crossover changes would be at the AVR, not at the sub. The sub should stay at the max setting you described to eliminate the double filtering Doc cautioned you against.

All the above is based on communication with Doc. I was keen to crossover to a planned sub at 50 Hz and he just warned me about possible problem of leaving that much bass in my mains. But he said try it and see. Just trying to pass “the learning” on.

As for the slate? Can always try it I guess, but before I spent money on slate, I’d try:
- moving the sub around to find the best response spot for the room, and
- find some scrap particle board, thick plywood or other dense media that’s big enough in the garage to get a feel for the change.
Then again maybe slate is cheap, but I know it’s very heavy…

kberg

Tour,

Understood. Thanks for your responses!

Tour2ma

Your Welcome..

BTW, Love the quote...