DIY, Faitals 18'' + RCF 940 in 950 horn, passive crossover + EQ, quite happy with them
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so you have 4 18" drivers but still use a sub.... interesting.
the faitals are in open air space so they do not hit low do they ?
what are your xover numbers if you dont mind.
btw, your speakers mounts are DOPE!!
did you did some welding ?
They are usable without subwoofers with enough correction. In my room ~35 Hz, sounds fine. But I already had subs before building these speakers. And subs play in this room from 17hz (not a lot of headroom, but enough for me). And as I demonstrated above — speakers + subs made it possible to get pretty good bass. This combination sounds great to me.
Xower: ~650 dipoles/horns, and subs + speakers work together below 100 Hz, as I describe earlier.
Speakers mounts made from plywood, two metal "sticks" (some standard stuff from a hardware store) and bolted joints, no welding, all made in the kitchen and in my yard
Turning drivers (besides the visual design)) gives some additional low-pass filter. Besides, the polarity of all drivers must be adjusted with a microphone, as with any other speakers. E.g. if you want to get positive polarity with the driver reversed, you need to change the connection on the terminals to the opposite.
I think it's off-topic
I saw a guy on the web talking about placing two subs very close to the listening seat, like one on each side, or two behind the seat. He said that this greatly reduces the effect of room reflections as you hear so much of the direct sound and the bass sound great. Has anyone tried this?
Many folks have posted here about using near-field subs, especially with dipole or Ripole designs. OTOH, Dr. Geddes has said that it takes the brain a couple of cycles to register deep bass tones. By the time that recognition takes place the bass has already had time to reflect multiple times around a normal domestic room, so even if the subs are close by the listener is experiencing a fully reverberant field and there is no true near-field bass. Any perceived benefit to the near-listener placement might be due to moving the subs within the room so that room modes are excited less, or at least differently.
Try it and let us know what happens!
Bill
Try it and let us know what happens!
Bill
Thanks Bill for the good reply. I can see how very close subs can sound good as the bass reflections from the room will be at a much lower level that the bass coming from the sub that is about a foot away from the listening seat. A friend of mine told be about the precedent effect where the loudest sound source will be the one we hear over a lower level source of the same sound. So I wondered if a very close sub would be what we hear over the bass reflections of the room, and if other people have found this to be true. If this is true it would really help dealing with un-even bass response at the listening chair if we could just place subs right by the chair and get a flatter listening experience.
I’ve never tried nearby subs, but I used to have four dipole subs the size of refrigerators at just above 1 meter distance. That was not in any way unaffected by the room, although a lot less than a single monopole sub at 4 meter distance.
However - I have the extreme version of multi sub setup - Double Bass Array with 24 subwoofers. Never heard speakers play headphone-quality bass before this.
However - I have the extreme version of multi sub setup - Double Bass Array with 24 subwoofers. Never heard speakers play headphone-quality bass before this.
Sure there is a fully reverberent field, but there *can be a rather large disparity in the pressure levels (intensity) between what's close to "near-field" and what is the reverberant field (..particularly as freq.s lower).
*with intensity/spl it becomes more difficult if you are sitting on-top of a room mode(s) "peak" that elevates the reverberant field to near or greater than that of the direct sound.
Moreover the brain processes time/phase delay, so along with pressure differences there are still perceived time/phase differences.
Time and intensity differences can actually result in some amount of externalization instead of internalization.
Notably: you can also achieve some amount of externalization by having the listener sit in the room's low pressure zone (relative to a certain bandwidth) and have sub(s) positioned to enhance the disparity in pressure differences between the listener's ears (usually one of which is in a higher pressure zone - often more laterally (angular) from at least one side of the listener).
Finally there is the matter of the freq. range itself, typically "sub woofers" are actually woofers that can often extend higher than 100 Hz and still be near the system spl-average - so a sub doesn't have to be only a "deep bass" reproducer.
-so basically while "near-field bass" (as a technical definition) might be an overly optimistic term (..for anything but headphones), in a reasonably well-setup design the result can be substantially different than a set-up we would typically NOT consider "near-field".
Also, (as I've previously mentioned) dipole bass (and particularly dipole stereo bass with the right positioning for "null" cancellation) can further effects that enhance externalization.
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"My room is 5 x 10 meters but fills every inch of it, and also plays 120 db 20 hz with headroom." .... Thats hard (but not impossible) to achieve with 6 good 15 inch (Sd 880) Pro drivers with 4 or 5 inch inch voice coils with 700 watts or 1,000 AES continuous power handling and high Bl low Mms motor / cones.
Its impossible with 6 Peerless 830847 with 466 Sd (11 inch not 12 inch which = 550 Sd as that fat rubber surround wastes 20% of the cone area) audiophile drivers with 2 inch voice coils which max out (reach Xmax limit) at 250 watts AES (forget the audiophile power ratings) ... Thats not a bass driver its a toy.
I only use sealed box not ported (yuk!) speaker so you can add approx 3dB to each of the sealed box sims if you use ported and want to achieve higher SPL at the expense of sound quality.
The sim shows both a single Peerless 830 847 and a 6 driver set up.
Just a few highlights of the Peerless driver... At 20 Hz using 250 watts the cone is travelling at its Xmax of plus/minus 12.5 mm (1 inch) bouncing around on its fat elastic band surround... Its max SPL at 20 Hz is.... Drum roll ... 97 dB !! So for a single driver, 100 Db requires 500 watts, 103 Db requires 1,000 watts 106 Db requires 2,000 watts, 109 Db requires 4,000 watts... You get the picture.
Doubling the drivers to use two instead of 1 results in a real world increase of approx 3 to 4.5 dB when distributed ie you dont gain the theoretical 6 dB for each doubling of Sd due to distributed source interference, so add 4.5 dB for every doubling of the surface area ie Add 4.5 dB for two drivers, add a further 4.5 dB for four drivers and add a final 2.25 dB for 50% increase from four drivers to 6 drivers... = 109 .25 dB AT 1 METER... But you have a 10 meter long room and according to you the Peerless "fill every inch of it with 120dB at 20Hz with headroom"... Oh really? Point sources drop off at 6dB with every doubling of distance, so your max 109.25 dB at 1 meter becomes 103.25 dB at 2 meters, 97.25 dB at two meters and 91.25 dB at 4 meters listening distance in your 10 meter long room.
So I would suggest that even if you sacrifice sound quality and go ported instead of sealed box to gain a few more dB, you are still a world (galaxy actually!) away from the 120 dB at 20Hz with headroom in every inch of your 10 meter long room...
They're PA subs with a 32Hz tune using 2x18s and for a large concert rig, not even that many of them. Yawn.