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Subwoofer Decision

I have narrowed my search to two choices though I am sure I will get comments steering me away from these.
Contrast Rythmik Audio 12G with Vandersteen 2Wq. I would like to get only one though I know a pair are best choice. Could maybe afford 2 Rythmik, but only 1 Vandersteen for now. The subwoofer would support Dali Helicons (4 ohms) biwired and driven by 2 mono McIntosh MC 252's at 500 watts each into 4 ohms. Living room size aprox. 24'x16'x8' placement not centered on 16' wall due to furniture (wife) constraints must stay put. Subwoofer placement needs also to stay there as well, I know this limits possible best choice for placement, my bad. There is room behind, next to, and between speakers. Any help help is appreciated.
128x128lowfreqguy
m-db's avatar
m-db
987 posts
 
Dunkirk. I thought it was just the theater I was in. That monotonous low frequency rarely letup throughout the film. It went on to win the Academy Award for sound?


Velodyne seems to be so busy with their LiDAR sensor development and production that their subwoofer marketing is almost non existent.

There wasn't much on the subwoofer market when I purchased their ULD-18 the first low distortion servo controlled subwoofer whose development has continued to their current products. Velodyne's DD Plus Auto EQ and the flexibility of the visual eight band nine parameter Manual/Preset Room Optimization enables almost limitless adjustability and indistinguishable system integration. 

Back panel connectivity is wide ranging. The remote controllability of polarity is useful on those recordings that reverse polarity from track to track while the six presets and gain are just too much fun.  
jsm71
141 posts
 

I've had my twin Rythmik F12Gs now for close to a month.  I still need to have a friend over to fine tune the phasing, but I'm very close.  These have exceeded my expectations, because playing with other subs never matched very well.  The way concert hall ambience comes forward in large scale orchestral pieces makes my speakers sound twice their price.  Big crescendos with concert bass drums put a smile on my face. My room treatments are also keeping order as intended.  

Electronic bass is never overdone, just supported.  Not overdoing the subs volume is key.  When a truly low note is on the recording, I now hear it, in proper pitch, not as a boom.  Recordings that used to simply boom are now cleaned up.  I couldn't be happier.

bdp24's avatar
bdp24
9,862 posts
 

Awesome jsm71! The continuously-variable phase control on the Rythmik plate amp makes getting that parameter optimized possible. The 0-180 2-position phase switch found on many subs is a joke!

One old trick for phase adjustment is to temporarily wire your speakers in opposite polarity (switch the positive & negative/red & black leads of your cables), then play a test signal of the 3dB-down point of the chosen crossover frequency between the speaker and sub, and adjust the phase control until the output of the opposite-polarity speaker and sub cancel out each other, creating a zero-sum null. Once the audibility of the test signal has been minimized (it's complete elimination is optimum), switch the speaker cables back to correct-polarity, reversing the plus & negative/red & black speaker cable leads back to normal. 

ieales's avatar
ieales
1,201 posts
 
A phase control is also a joke as it is not constant phase across the subwoofer’s range. For example, at 90° setting shift is 80° at 20Hz, 120° at 40Hz and 150° at 80Hz. Best option is BOTH phase control and 0-180 switch.

Adjusting XO frequency changes the phase.

The wrong way to go about it is to preselect a crossover frequency. It’s been my experience that with the same hardware, the XO frequency is highly room, and to a less extent amp, dependent and picking XO by the numbers is not the way to proceed. Main amplifier choice can necessitate a different XO frequency for the same speakers in the same room.

Adding extra cable and additional connectors to run ’through’ the sub is counter productive. Cable interaction could just as likely negatively impact the entire system.

It my experience, the best way to integrate a sub is add a High Pass to the main amp, drive the sub at line level with a simple high quality Y and adjust the sub to integrate. See http://www.ielogical.com/Audio/#SmallestThings for our last XO. The disadvantage of this method is the filter must be matched to the amplifier input impedance. Swapping amps will require a second XO. A distant 2nd best is to use an electronic XO and run the sub wide open. An electronic XO can be a useful tool to find more quickly the sweet spot than soldering capacitors in a passive XO. The main problem with some electronic XO is that the low and high pass frequencies are linked and filter order is usually fixed and steep. A sub with multiple filters and phase controls may allow better integration of frequency, slope and phase.

As far as fast or slow, it is well integrated and not. All to often, the wrong XO frequency is selected and phase is horribly wrong. WAF be damned, sometimes "The sub MUST be placed HERE!!!"

For some background on subs and their operation see http://www.ielogical.com/Audio/SubTerrBlues.php/
For just setup suggestions see http://www.ielogical.com/Audio/SubTerrBlues.php/#Setup
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