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#95849 - 06/24/16 01:25 PM Re: Ultra-X12 Subwoofer Floor Loading [Re: Uncle Steve]
Uncle Steve Offline
Deputy Gunslinger

Registered: 05/08/16
Posts: 11
Well, I believe that we have digressed entirely from my original ‘post’.

In my 75+ years, starting in the 60’s, I have built Heath and Dynaco kits, both audio and analyzers; I have also built and/or modified a number of loudspeakers and cross-overs (with the help of LEAP). I currently have a number of audio systems (all stereophonic) including my old Dynaco ST70 Amp/PAS3 Preamp/FM tuner, plus Phase Linear Amp and Preamp, Adcom, Hafler, etc.; I also possess Duntech PCL 3 speakers (excellent), Magnepans, ESS Transtatic I’s (old,1972, but still produces one of the finest sounds around . . will empty your cupboard and rattles your doors at 15 Hz, and the ultrasonics will drive your cat insane), and KEF LS50’s (for background music).

My original ‘posting’ was to determine the optimum height of this downward firing subwoofer above a wood floor. My experience indicates that with such an arrangement the floor actually becomes part of the speaker, with respect to both driver/vent loading and vent length/action. I have a 65” SONY Bravia TV with built-in, front mounted 3-way speakers, supplemented with the SONY wireless sub. This 8” sub produces better, cleaner (if not as deep) bass than the Ultra X-12: a bass drum has ‘impact’ and is taut, versus X-12’s ‘muddy’ sound (as if was under a blanket!).

My wife likes the appearance of the X-12 so if I cannot obtain better, cleaner bass from it I will probably gut it, invert it, Drylok it and make it into a planter. I have already spent too much time and effort on this subwoofer.

Thanks for your replies, though.

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#95850 - 06/24/16 02:40 PM Re: Ultra-X12 Subwoofer Floor Loading [Re: Uncle Steve]
XenonMan Offline
Desperado

Registered: 04/08/08
Posts: 2676
Loc: Columbus,North Carolina
I guess I read your post right the first time. The GRAMMA isolation pad is designed to eliminate the floor from becoming part of the speaker. It uses some heavy duty high density pads that are about 3 inches thick and is mounted to a carpeted piece of MDF for the sub to sit on. It raises the sub off the floor about 3-4 inches and lets the sub breath a little better. I have the first version which is as described. The newer version doesn't appear to give the same rise.
_________________________
Music system
Model 990/7500/Magnepan 1.6 QRs/Technics SL1200 MK2/Aperion S-12 Subwoofer/OWA3/Sony NS75H DVD
APC H15 Power Conditioner

TV System
Large Advent Loudspeakers/ Polk center/Monoprice surrounds/Panasonic Viera 42 inch/Onkyo HT-RC260/Sony BDP S590/Directv


Home Theater System
Onkyo PR-SC886/Outlaw 7125 Klipsch RF-82 L/R,RC-62 center, RB-35 SR/SL, BENQ HT1075, Outlaw LFM1-EX/OPPO BDP-83/Directv
Harmony ONE
Blue Jeans and Monoprice interconnects
APC H15 Power Conditioner

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#95851 - 06/24/16 05:03 PM Re: Ultra-X12 Subwoofer Floor Loading [Re: Uncle Steve]
Helson Offline
Gunslinger

Registered: 03/21/12
Posts: 283
Loc: USA
I have an Ultra-X12 that has replaced my LFM-1 Plus. I love it and I'm quite happy with my decision to replace the Plus. The bass response, I find, is very tight and precise. I also have it on hardwood flooring using the spikes/discs, but haven't experienced any "loading" or undesirable muddiness.

Since introducing it into my system several months ago, I've enjoyed an improved listening experience from what I had with my previous sub.

One example...
Playing "Edge of Tomorrow's" opening scene, which contains some extremely low bass, demonstrates to me the X-12 can reproduce accurate, precise bass at these low levels and every desired frequency above those.
Just my 0.2¢.
_________________________
Main HT <> 976 <> 7200 <> Ultra-X12 <> sapphire ST2 mkII RF/LF <> sapphire SC center
sapphire ST2 mkII SBR/SBL <> sapphire SS SR/SL <> Verizon/DVR <> Vizio M70Q7 <> Oppo UDP-203 <> Amazon 4k Fire TV

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#95852 - 06/24/16 05:17 PM Re: Ultra-X12 Subwoofer Floor Loading [Re: Uncle Steve]
Outlaw Ben Offline

Gunslinger

Registered: 10/31/13
Posts: 241
1.25" to 1.5" is the proper height to make sure you do not have an issue with cabinet/vent loading. This is the required amount of space to allow the driver to displace enough air that it can properly go through compression and rarefaction. If using the Outlaw feet, you are fine. The Ultra is a very tight sub, as the internal bracing eliminates most cabinet resonances and the Class LH amp tracks the audio signal - if you are experiencing 'muddy' sound, I would also recommend an isolation pad to decouple the sub from the floor.

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#95853 - 06/24/16 08:36 PM Re: Ultra-X12 Subwoofer Floor Loading [Re: Uncle Steve]
XenonMan Offline
Desperado

Registered: 04/08/08
Posts: 2676
Loc: Columbus,North Carolina
Voila!!
_________________________
Music system
Model 990/7500/Magnepan 1.6 QRs/Technics SL1200 MK2/Aperion S-12 Subwoofer/OWA3/Sony NS75H DVD
APC H15 Power Conditioner

TV System
Large Advent Loudspeakers/ Polk center/Monoprice surrounds/Panasonic Viera 42 inch/Onkyo HT-RC260/Sony BDP S590/Directv


Home Theater System
Onkyo PR-SC886/Outlaw 7125 Klipsch RF-82 L/R,RC-62 center, RB-35 SR/SL, BENQ HT1075, Outlaw LFM1-EX/OPPO BDP-83/Directv
Harmony ONE
Blue Jeans and Monoprice interconnects
APC H15 Power Conditioner

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#95883 - 07/13/16 10:53 AM Re: Ultra-X12 Subwoofer Floor Loading [Re: XenonMan]
Uncle Steve Offline
Deputy Gunslinger

Registered: 05/08/16
Posts: 11
But, if the loudspeaker design intends the floor to be part of the speaker (similar to a more complex multi-cavity enclosure), then raising the subwoofer will defeat the original design intent
Anyway, I have been sending out 'feelers' to find a vintage ACOUSTICAL MFG, Ltd (later "QUAD") 50's full-range corner ribbon speaker in good, working condition. Exquisite design and cabinet. Virtually extinct.

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#95884 - 07/13/16 05:56 PM Re: Ultra-X12 Subwoofer Floor Loading [Re: Uncle Steve]
XenonMan Offline
Desperado

Registered: 04/08/08
Posts: 2676
Loc: Columbus,North Carolina
The GRAMMA doesn't just raise the sub off the floor. It provides a raised, isolated platform for the sub to sit on. Subs don't intentionally try to make the floor part of the speaker although sometimes they can. Otherwise designers would have to give different specs for different floor stiffness and design.
_________________________
Music system
Model 990/7500/Magnepan 1.6 QRs/Technics SL1200 MK2/Aperion S-12 Subwoofer/OWA3/Sony NS75H DVD
APC H15 Power Conditioner

TV System
Large Advent Loudspeakers/ Polk center/Monoprice surrounds/Panasonic Viera 42 inch/Onkyo HT-RC260/Sony BDP S590/Directv


Home Theater System
Onkyo PR-SC886/Outlaw 7125 Klipsch RF-82 L/R,RC-62 center, RB-35 SR/SL, BENQ HT1075, Outlaw LFM1-EX/OPPO BDP-83/Directv
Harmony ONE
Blue Jeans and Monoprice interconnects
APC H15 Power Conditioner

Top
#95889 - 07/14/16 01:25 PM Re: Ultra-X12 Subwoofer Floor Loading [Re: XenonMan]
Uncle Steve Offline
Deputy Gunslinger

Registered: 05/08/16
Posts: 11
RE my previous post, yes, my sources have all indicated that the "QUAD" loudspeaker I mentioned does appear to be extinct; a carcass or two might be found in an English attic.
I found a review of this "Corner Ribbon Loudspeaker" in "Wireless World", December 1950 issue, page 29. From the article I have concluded that all of these (I believe) magnificent loudspeakers have been 'incinerated' by the advent of more powerful, double digit Watt amplifiers.
Short of a human sacrifice, I do not believe I will get my wish for a pair, much less one, of these beauties. Amazingly priced at £83, including installation! Of course 1950 £83 translates, based on the 1950 £ to $ conversion rate and the inflation factor, to only a mere $1,100. Nothing of this caliber could be produced today for anything close to 10X this price, considering stunning finish (even the hidden sides) and complex interior bass acoustic filter structure.
Thanks for everyone's advice on my X-12 question; I appreciate the replies. Will try the absorption pad . . . a cheap option.

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#95891 - 07/14/16 02:18 PM Re: Ultra-X12 Subwoofer Floor Loading [Re: Uncle Steve]
XenonMan Offline
Desperado

Registered: 04/08/08
Posts: 2676
Loc: Columbus,North Carolina
The Quad ESL is still being made in an updated form by the same company, Quad-hifi. Google quad esl and you will find it. There is also someone rebuilding the originals but that is very expensive. I have a pair of Magnepan 1.6 which although different in form, operate on the same principle and are awesome for music. They are also reasonably priced. Check out http://www.magnepan.com/index
_________________________
Music system
Model 990/7500/Magnepan 1.6 QRs/Technics SL1200 MK2/Aperion S-12 Subwoofer/OWA3/Sony NS75H DVD
APC H15 Power Conditioner

TV System
Large Advent Loudspeakers/ Polk center/Monoprice surrounds/Panasonic Viera 42 inch/Onkyo HT-RC260/Sony BDP S590/Directv


Home Theater System
Onkyo PR-SC886/Outlaw 7125 Klipsch RF-82 L/R,RC-62 center, RB-35 SR/SL, BENQ HT1075, Outlaw LFM1-EX/OPPO BDP-83/Directv
Harmony ONE
Blue Jeans and Monoprice interconnects
APC H15 Power Conditioner

Top
#95913 - 07/21/16 01:49 PM Re: Ultra-X12 Subwoofer Floor Loading [Re: XenonMan]
Uncle Steve Offline
Deputy Gunslinger

Registered: 05/08/16
Posts: 11
While listening to my Ultra X-12 and thinking about subwoofer sound, another thought popped into my head: listening room construction. When I lived in NYC, Manhattan all of my apartments had thick plastered interior/exterior brick walls, rather than the sheet rock over 2X4 wood studs construction of my house here in Texas (which my English friends referred to as ‘stick and wattle’). I remember having to use a rotary impact drill with a long carbide drill bit, and a lot of force, to drill holes to run wire from room to room. My first experience here with that drill here resulted in a drill chuck size hole, with the drill bit protruding into the next room as soon as I started the drill!
Thinking that over, I am fairly certain that the flimsy, thin wallboard vibrates with low bass frequencies, absorbing then releasing energy which may make low bass sound ‘muddy’. I do not have a laser interferometer to measure wall ‘bending’ modes, so my thoughts are not confirmable. Could wrong, but there may be some truth in this as I have read about loudspeaker manufacturers using interferometry to measure and control cabinet resonances. And, loudspeaker cabinets are a lot smaller than my large listening room walls and, especially, the much less braced ceiling. Thoughts?

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