Forward firing, downfiring or sideways? - Home Theater Forum and Systems -

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post #1 of 8 Old 10-28-06, 01:14 PM Thread Starter
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Forward firing, downfiring or sideways?


There are all sorts of rumours concerning different driver configurations and their perceived advantages.

There are those that believe that forward firing produce the best impact. The "chest thumpers" if you like. The gorilla type sub.

Then there are the downfiring subs which can shake the house down but still (allegedly) don't hit you hard in the chest. The floorbanger sub.

A third type is the sideways firing sub. Merely by orientation of the box your drivers in a forward firing sub are pointing along the back wall rather than at the listener. Do they hit you in the chest or shake the house down?

The reason I ask is because my IB fires along the back wall. When I'm in the hot seat the drivers are pointing at roughly 90 degrees to my viewpoint. I don't get hit in the chest even at 120dB.

By sheer coincidence my browsing chair is directly inline with the drivers but further away than the hot seat. I sometimes suffer discomfort from music with a heavy repetitive bass beat when I'm browsing. But not when I'm sitting in the hot seat.

This suggests some sort of beaming is going on even though the crossover point is below 80Hz. It could be sheer coincidence that my browsing chair is at the pressure node of the half wave which is causing the discomfort.

Any thoughts? It should be easy to rotate a powerful forward firing box sub to test whether beaming is taking place. I just don't happen to own such a sub.

I have seen SVS owners removing the floorplate from their downfiring sub to sit in line with the naked drivers with the sub on its side. What do they know that we don't?
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post #2 of 8 Old 10-28-06, 02:16 PM
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Re: Forward firing, downfiring or sideways?

Interesting, I get chest thumping bass everywhere in the room.
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post #3 of 8 Old 11-12-06, 11:55 AM
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Re: Forward firing, downfiring or sideways?

I've owned front firing(JBL PSWD112), down firing(Hsu VTF-3 MK2) and side firing(Hsu VTF-3 HO w/turbo). I did try the down firing VTF-3 MK2 as a front, side, rear and even straight up firing sub and it seemed to hit the same no matter the orientation. The VTF-3 HO w/turbo is side firing and hits hard as . I've tried it front firing and it seems to hit just the same. In my room the orientation doesn't seem to matter for how hard they hit. What changes in my room based on orintation is how they sound. The HO firing to the side sounds the best in my room.
post #4 of 8 Old 11-12-06, 10:44 PM
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Kipp Jones
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Re: Forward firing, downfiring or sideways?

I prefer front or down firing.

Have you driven an SVS lately???
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post #5 of 8 Old 11-15-06, 10:00 AM
Andrew Pratt
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Re: Forward firing, downfiring or sideways?

The wave length's of sub base is so long that it doesn't matter which way the driver is facing. If you're feeling more base at one location then another its most likely due to differences in SPL due to standing wave cancelations that are occuring at other places in the room. Do you have an SPL meter? If so play some test tones and see if there isn't a huge difference between the two locations.
post #6 of 8 Old 11-15-06, 12:33 PM
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Re: Forward firing, downfiring or sideways?

Yeah, chest thumping should be a matter of pressurization/spl. The trend I have noticed is that those who use downfiring configurations seem to get better in room FR on the whole. It's definitely not cut and dry or all encompassing by any means, and it could be just a big coincidence, but in general, I've noticed it to hold pretty true.
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post #7 of 8 Old 11-29-06, 04:58 PM
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Re: Forward firing, downfiring or sideways?

FWIW, we had a couple of friends round the other night to watch Pirates of the Caribean DMC and generous soul that I am, I allowed them and the wife to sit in the 'listening position' and the two seats adjacent. This left me sitting in the one position next to a wall. I spent two hours suffering staggeringly overblown bass that rattled every tooth in my head. In the light of Chris's comments at his surfing position, I can easily believe that he is sitting at a reinforcement node. I'll bet it's about 30 to 35Hz. This is a problem I hadn't even considered, until enforced proximity with a room boundary and it's surfeit of reinforced frequencies.

As regards DF or FF, I'd always assumed the directionality of bass (or lack of it) to mean it was purely an asthetic concern. However, in the smaller European room potential sub positions are more limited. You've kinda got to fit them in where you can.

I recently helped a friend set up his new SVS SB12 with my SMS-1 as an aid. He only had two positions it could sit in with a few inches either way for tuning.

In the process of the afternoon that followed, I turned the sub with driver to the wall, along the wall and away from the wall. The position in question was best about 12"out from the wall but there was no room to move it further. With a DF that would have been the limit of choice; 0-12". With the FF SB-12 it gave the option of driver against the wall (0") to the 12" position with the driver facing out (19"). I tried all the variations with the sub facing forward, back, left and right, within the room available before finally settling on the final position.

A DF could not have allowed this.


Mitsubishi HC6000 : Carada 88" Precision Series screen : Sony PS3 : Audiolab 8000CD : Audiolab 8000AP : Cinepro 2k6 : XTZ 99.25 fronts & center : M&K Xenon 25 and LCR 25 surrounds : BFD : EP4000: Dual AV15-X 4cu ft sealed subs
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post #8 of 8 Old 02-08-07, 01:32 AM
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Re: Forward firing, downfiring or sideways?

Look for a dip/peak at 35hz.
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downfiring , firing , forward , sideways

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