[danvprod]

My P.I. Audio Group power cable for the PS Audio Gain Cell DAC came yesterday and I am working on breaking that in. I used the EQ function on the A370 amps to tame the peak at 43 Hz, which isn't going to be fixed by adding more traps because it's so low in frequency. The PEQ works well for this and flattens it right out.

Above is the L+R channel with and without the PEQ engaged.

I'd still like to eventually get a GR servo sub (a sealed one) positioned out-of-phase behind my PLM. I suspect this will help to "remove the back wall" since I don't have the luxury to sit too far away from the back wall and can't put diffusion there as I would normally do in a room to tame the rear-wall reflections.

[Danny Richie]

Keep in mind when trying to even out the response to just look at one speaker at a time. If you play both of them at the same time then you can get peaks and dips caused by the time arrival differences of the two speakers and their room reflections.

[danvprod]

Keep in mind when trying to even out the response to just look at one speaker at a time. If you play both of them at the same time then you can get peaks and dips caused by the time arrival differences of the two speakers and their room reflections.

Yes, Danny, good point. The plot above was just the combined to show the effect, but I set the PEQ for each A370 independently to flatten each channel first and then also measured together.

BTW, removing the MacPro from my room has drastically reduced the noise floor (and amount of heat generated). I'm down to about 35.5 dB(A) and NC 32, which is pretty quiet. I don't have measurements from before removing the tube amp, adding the Mod-86 (going balanced), removing the noisy sub outs of tube amp and removing all the fans, but I figure close to a 6-8 dB drop in the noise floor.

Now I can hear the following:
* spinning hard drives (SSD boot drive, but 2 HDD backup drives, which can be heard if they are spun up). I've moved all my loseless music to a SD card, which is plugged into the Mac Mini, it is silent).
* Slightest transformer hum from each A370 amp.
* Some hum 60/120/180 components from the servo subs (acoustic, not electric).
* Slight hiss from co-ax.

[dlynch34]

@Shakey, @Greg --

XO and phase and level were set based on measurements to try and get the flattest bass response in-room taking into account modal behavior.

I worked with @poseidonsvoice extensively on this. Updated A370 amp settings above an also here (4/26/2018):




so I just bought a pair of these and finally getting to a point of hooking them up.  Looking at the picture do I only hook up the line in to my preamp?  What about the speaker connector section of the Super V's?  Sorry I have not had a pair like this and trying to figure out the hook up scenario.



If you look at my subwoofer plot, you can see that there are attemps made to get the aggregate response of the subwoofers as flat as possible. That was only possible in my room by adjust the delay/phase crossover and level controls and ended up with asymmetrical XO slopes electrically to try and match the acoustic response in-room and have proper slopes acoustically. You can also see that they is a big modal dip on the left channel and a peak on the right channel, the resulting trace is pretty flat from just two subwoofers, and ones that are tied to the position of the overall speakers. Perfect world, I'd have four of these in a "swarm" to try and flatten the bass response even more. 

[mlundy57]

You can use either the low/line level (RCA) or the high/speaker level (binding posts) inputs. Which one you choose depends on whether you use an inline filter to keep the first octave (20-40Hz) signals away from the midrange driver.

If you do not use a filter you can connect the sub amp using either the low level input connected to the preamp by RCA interconnects or you can bi-wire from the power amp binding posts to the sub amp binding post. Another approach would be to run one pair of speaker cables from the power amp to the Super Vs then connect a second pair of speaker cables from the Super V binding posts to the sub amp binding posts. This uses less speaker wire but I don't know if the additional length of speaker wire to the sub amp would be enough to cause any phase shift. There is one big WARNING with this approach. You have to Bi-Wire, both pairs of speaker wire to the same pair of binding posts (unless you power amp happens to have two pair of binding posts that are connected in parallel). Whatever you do, do not bi-amp. I made this mistake once and blew up my amp.

If you do use an in-line filter to roll off the low end to the midrange driver, you have to use the low/line level inputs on the sub amp connected via RCA to the preamp. Since you are limiting the low frequencies to the power amp, there won't be any low end signal at the speaker binding posts to send to the sub. An added benefit of this approach is that since the power amp doesen't have to deal with low frequencies, you an use a lower powered amp for the midrange and highs.

Mike

[dlynch34]

You can use either the low/line level (RCA) or the high/speaker level (binding posts) inputs. Which one you choose depends on whether you use an inline filter to keep the first octave (20-40Hz) signals away from the midrange driver.

If you do not use a filter you can connect the sub amp using either the low level input connected to the preamp by RCA interconnects or you can bi-wire from the power amp binding posts to the sub amp binding post. Another approach would be to run one pair of speaker cables from the power amp to the Super Vs then connect a second pair of speaker cables from the Super V binding posts to the sub amp binding posts. This uses less speaker wire but I don't know if the additional length of speaker wire to the sub amp would be enough to cause any phase shift. There is one big WARNING with this approach. You have to Bi-Wire, both pairs of speaker wire to the same pair of binding posts (unless you power amp happens to have two pair of binding posts that are connected in parallel). Whatever you do, do not bi-amp. I made this mistake once and blew up my amp.

If you do use an in-line filter to roll off the low end to the midrange driver, you have to use the low/line level inputs on the sub amp connected via RCA to the preamp. Since you are limiting the low frequencies to the power amp, there won't be any low end signal at the speaker binding posts to send to the sub. An added benefit of this approach is that since the power amp doesen't have to deal with low frequencies, you an use a lower powered amp for the midrange and highs.

Mike

ok so I do not have a inline filter to my knowledge.  So Here is where I guess I am getting stuck.  I hooked up the rca to the low level input and put that into the anthem processor I have ..I assume maybe I am wrong this goes to the left front or right front channel of my preamp?  I then connected speaker to the post of the subamp as shown then to my amp... I hope the picture can give a better description... clearly I am missing something here and do not want to damage anything before proceeding... 

[Captainhemo]

You should  be able to  just run  from   your pre-amp (variable out)  to the  amp and  low level inputs of the sub amps . If you don't have  2 sets of variable outs on the pre,  just use an rca Y  harness for each channel. 
Obviously send the  signal from the right pre out to  the right sub amp,  left pre out to left  sub amp.  You only need populate  one  low level input on each sub amp ( I think the left has the auto on trigger)).   If you  populate both inputs (same channel split itno 2 cables)  you'll get  an extra 6 db of gain out  of the amps.
You  won't  ned the high level inputs

jay

[danvprod]

And you really don't need a line filter either @dlynch34. As Danny explained to me (and the reason I had so much trourble with my 2.5watt tube amp and am so much happier with the performance of the system with the Mod-86 amp). The mid-bass co-axial driver's impedance rises rapidly at it's Fs, so it never sees much if any power. It's a built in protection mechanism and doesn't need a line-level filter (adding one won't hurt).

[mlundy57]

ok so I do not have a inline filter to my knowledge.  So Here is where I guess I am getting stuck.  I hooked up the rca to the low level input and put that into the anthem processor I have ..I assume maybe I am wrong this goes to the left front or right front channel of my preamp?  I then connected speaker to the post of the subamp as shown then to my amp... I hope the picture can give a better description... clearly I am missing something here and do not want to damage anything before proceeding... 

That setup on the sub amp box is different than the way my Subs are wired.

What are the speaker cables that are plugged into the tube connectors at the bottom of the A370 amp box plugged into at the other end of the speaker cable?

[dlynch34]

I am all good now thanks everyone.  I got some Y splitters to resolve the issue.  Now I need to configure my subs to be included for movies..

[mlundy57]

I am all good now thanks everyone.  I got some Y splitters to resolve the issue.  Now I need to configure my subs to be included for movies..

For that you really want a subwoofer designed for home theater use, either sealed or ported. I’ve had issues in the past with open baffle subs connected to the subwoofer (LFE) output of an HT receiver. Some of the special effects would cause the drivers to bottom out. To prevent that, I added a sealed sub to the system and connected it to the HT receiver’s subwoofer output.

To clarify, I am using two 8ohm drivers. This gives me a 4ohm load for the speakers and allows me to use the full power of the A370 amp. If your Vs have two 16ohm drivers you may not experience the problem I did since you would be presenting an 8ohm load to the amp. This would limit the power from the amp and could prevent the bottoming out.

I have connected both main and sub channels to the same subwoofer in the past but the amp was an A370PEQ3 instead of the A370PEQ. The difference is that the PEQ3 has two sets of line level inputs. The PEQ has one set of line level inputs and one set of outputs.

My advice is get a sealed sub that is designed for HT use. When I first had the problem I asked Brian Ding of Rythmik about it. He told me the OB subs were designed for music while the sealed or ported subs were designed for HT. Using the proper tool for each job will give the best results.

Mike

[Captainhemo]

I am all good now thanks everyone.  I got some Y splitters to resolve the issue.  Now I need to configure my subs to be included for movies..

 

[dlynch34]

I actually have a sealed sub that I want to use for movies and just the Super Vs for music.  My question is what is the recommended crossover setting for the Vs when I have it in movie mode with my sealed sub?

Thanks

[mlundy57]

I actually have a sealed sub that I want to use for movies and just the Super Vs for music.  My question is what is the recommended crossover setting for the Vs when I have it in movie mode with my sealed sub?

Thanks

I let mine run full range then set the sub to LFE only

Mike

[danvprod]

I added a new picture of the current set up after adding in two GIK QRD diffusers behind the Vs and a additional bass trap behind the listening position.

[danvprod]

I played around with positioning today after reading Lynn Olson’s article on ideal speaker positioning. Basically, I decided to bring the speakers into a 6’ equilateral triangle and toed them in much more such that they crossed about a foot in front of my MLP.

Originally I had these about 8’ apart. So I moved them each in about a foot. Sub amps were tweaked a bit as well. I need to do more listening but it’s an improvement. One of my biggest challenges with the Vs is their phasey central image. This helps a great deal. Plus I still have imaging outside the speakers.

This also seems to address some issues with a 370hz peak I have in my room and extends the response up to 20kHz.