[Early B.]

BACK AGAIN....

My attempt to use my HT sub was a temporary solution two years ago, but it didn't last very long due to connectivity issues. Nevertheless, it convinced me that a rear sub for my 2-channel system was in my future. Well, the future is now.

I finally assembled a third dual OB servo sub and placed it a couple of feet behind the listening position near the rear wall. With a low crossover setting and set out of phase, it blends seamlessly with the front subs. However, I only spent 15 minutes listening and tweaking, but it sounds great so far, as expected. I'll resume listening and tweaking after Christmas when I have more time. No pics worth posting yet.

What I said earlier in this thread when I was using my HT sub still applies, but cleaner and better: "Gut wrenching, bowel busting, ball tingling bass!"

I placed an order for an amp box from mlundy57. Once it arrives, I'll clean up the wiring with Neutrik connectors.


P.S. -- the WAF Police hasn't done a drive-by yet. Let's hope I don't get a speeding ticket.
   

[JLM]

If you follow the teachings of Earl Geddes, Floyd Toole, and our own Duke LeJeune you'll discover the concept of using a subwoofer "swarm" to tame inherent in-room bass peaks/dips.  In his seminal work "Sound Reproduction" Toole explains how bass behaves like waves and that those waves can double up, cancel, etc. due to the room size and shape (like waves in a shallow tub).  Geddes points out that physical problems can best (only) be cured via physical means (not DSP).  LeJeune sells a well received swarm system.  The concept works with 3 but more frequently 4 subs located near corners. 

[Early B.]

If you follow the teachings of Earl Geddes, Floyd Toole, and our own Duke LeJeune you'll discover the concept of using a subwoofer "swarm" to tame inherent in-room bass peaks/dips.  In his seminal work "Sound Reproduction" Toole explains how bass behaves like waves and that those waves can double up, cancel, etc. due to the room size and shape (like waves in a shallow tub).  Geddes points out that physical problems can best (only) be cured via physical means (not DSP).  LeJeune sells a well received swarm system.  The concept works with 3 but more frequently 4 subs located near corners.

I'm familiar with their work; their research is what prompted me to try a third sub. Since open baffle subs load the room differently than typical sealed subs, it would be interesting to see how an OB swarm would perform. I'd love to add a fourth sub, but my room configuration won't allow for it. 

[mlundy57]

The number of subs required to smooth out the bass responds has a lot to do with the number and placement of different seating positions. A listening room with only one seat is much different than a room with multiple rows of seats. The more seats, the more subs needed to get good bass at all positions. It’s another case of one size doesn’t fit all.

[cujobob]

Has anyone had luck using Room Correction to integrate multiple subwoofers? Doing it manually can be quite a chore.

[HAL]

Yes, I did it for a customer with 2 front and 2 rear subs with a DSP crossover using time delay.  Integrated very well. 

Try using Room EQ Wizard and calibrated mic for measurements at the listening position.  Start with one sub at a time.  Even a RadioShack SPL meter will work with a warble tone CD.

[Early B.]

Has anyone had luck using Room Correction to integrate multiple subwoofers? Doing it manually can be quite a chore.

Yeah, if someone has a youtube video link or simple instructions for the non-tech savvy on how to integrate multiple subs, please provide it here. I don't know where to start, so I'm relying solely on my ears.

One of my recommendations to Danny was to do a Tuesday Tech Talk where he actually goes into someone's home and shows us how to conduct measurements, recommends treatment options, makes speaker placement suggestions, and sets up the open baffle subs properly.

[nickd]

From HAL,
"Try using Room EQ Wizard and calibrated mic for measurements at the listening position.  Start with one sub at a time.  Even a Radio Shack SPL meter will work with a warble tone CD."

Thanks HAL,
I have 2 custom floor standing monitors Danny just re-worked for me. They are built with down firing 12" sealed servo subs built in to the bases. I have 2 more 12" sealed boxes left over from an older Super V project. I will build out the other 2 subs in the next month and start working on a true "Servo Swarm". 

I use a Lyngdorf Digital amp so running Room Perfect is in the plan. I have always considered setting up the Swarm properly daunting. Honestly I never broke it down to setting up 1 sub at a time. I can wrap my head around that. I have always had issues trying to get the phase perfect in outboard subs. I suppose Room EQ wizzard might help with that. I have a good Mic and stand (came with the Lyngdorf TDAI 270). but i think I need a good outboard sound card for the program to work properly. My Dell laptops are not set up for high end audio measuring. 

From CujoBob,
"Has anyone had luck using Room Correction to integrate multiple subwoofers? Doing it manually can be quite a chore.
Bob, The DSP can do miracles on the room, but I don't think there is any shortcut to proper placement, phase, PEQ settings etc. Think I have to spend a Saturday doing measurements and adjusting subs. Then run Room Perfect to lock it in.

Some day, I hope someone will make a digital amp that can switch between Dirac, Anthem, Room Perfect, etc. like Dolby or DTS processing in a HT receiver. It would be nice to pick which one you like best. I'm very happy with Room Perfect, but the audiophile in me wonders if the others offer different flavors of DSP goodness.

[Tyson]

For a swarm, I'd recommend starting with a sub in each front corner, the 3rd sub placed along a side wall and the 4th sub placed along the rear wall. 

[Danny Richie]

nickd, you already have servo subs built into your main speakers. You can just add a pair to the back of the room and you're done.

And did you ever get those speakers built out and playing yet?

I have a gut feeling that those will be very good.

[Early B.]

I have 2 more 12" sealed boxes left over from an older Super V project. I will build out the other 2 subs in the next month and start working on a true "Servo Swarm". 

Nick -- We'd love to read about your experience with building a servo swarm!

[Early B.]

Here's a shot of my third sub. It's next door neighbor is my HT sub. Love the finish on that thing. Amp box install and wiring clean up will probably be the first audio project for the new year.

BTW -- room is 13x20x8.


 

[poseidonsvoice]

Yeah, if someone has a youtube video link or simple instructions for the non-tech savvy on how to integrate multiple subs, please provide it here. I don't know where to start, so I'm relying solely on my ears.

One of my recommendations to Danny was to do a Tuesday Tech Talk where he actually goes into someone's home and shows us how to conduct measurements, recommends treatment options, makes speaker placement suggestions, and sets up the open baffle subs properly.

I wrote this years ago:

https://www.audiocircle.com/index.php?topic=155030.msg1659006#msg1659006

Recently I helped a colleague who had a pair of GR Research NX Otica’s with Triple 12 inch OB/Rythmik’s as all of you know. Bass was good but not perfect. He added 2 more sealed subs and now it is golden. Did everything with REW and a MiniDSP to integrate the sealed subs. Done.

Pretty much everything we/he did is in that thread I linked above which has several systematic requirements and articles to read (which give you detailed instructions!). It’s a learning curve but very do able. Each person’s room and situation is different so the 1st thing that must happen before you integrate the subs is you must become an expert at measuring your room/speaker system. REW is popular and free and constantly upgraded. There are entire forums dedicated to it so I would definitely work at it. Hate to say it and as I learned years ago, you have to shovel some poop to reach nirvana with bass! A rite of passage so to speak! On my last effort I integrated 4 subs over a weekend. Once upon a time it took me an entire month to do.

Best,
Anand.

[Early B.]

I wrote this years ago:

https://www.audiocircle.com/index.php?topic=155030.msg1659006#msg1659006

This is awesome. It should be a sticky somewhere.

[poseidonsvoice]

Early B,

Thanks for the complement, but honestly on this forum there is very little if any interest in achieving bass perfection through REW and measurements. Everybody wants one stop shopping and the easy way out!

I'll leave you guys with this:

LF response, 50 dB vertical range, 5 dB vertical scaling, no smoothing:



LF response, 70 dB vertical range, 10 dB vertical scaling, no smoothing:



LF response, 50 dB vertical range, 5 dB vertical scaling, 1/12th octave smoothing:



LF response, 70 dB vertical range, 10 dB vertical scaling, 1/12th octave smoothing:



LF response, 70 dB vertical range, 10 dB vertical scaling, 1/12th octave smoothing, with Target Curve overlay:



LF response, 50 dB vertical range, 5 dB vertical scaling, psychoacoustic smoothing:



That is what you get with didactic measurements and (4) asymmetrically distributed subs. Took me 3 days, 6 hours each day. The ramp up in the bass from 150Hz to 20Hz was on purpose, subjectively sounds a little more dynamic on the lowest octaves. The dip around 50Hz is a ceiling mode which is audibly harmless as you can tell in the 1/12th octave smoothed measurements and is also a very small range of the bass spectrum. The area close to 200Hz is the Schroeder frequency transition. Room dimensions are 16 feet wide, 10 feet tall, and 26 feet deep. The only area of boost EQ that I have is around 15-30Hz. There is no EQ from 30Hz up through 300Hz. Just overlapping of subs, xo points, xo slopes, gain, and phase. No delay used at all. Subjectively, it's hard to tell you what it sounds like, it has to be experienced. On my next post, I'll show the waterfalls (CSD) in the under 300Hz range if there is any interest.

If you guys have questions, please ask.

Best,
Anand.

[guf]

I wrote this years ago:
Each person’s room and situation is different so the 1st thing that must happen before you integrate the subs is you must become an expert at measuring your room/speaker system. REW is popular and free and constantly upgraded.

A quick google search reviels that to become and expert 10000 hours is required.  Some quick math on my phone... 416 days 24 hours a day. UGH!.  When I attempted this it was a struggle. Sure i didn't try for 4 years at 8 hours a day but i put in a good effort.   I bought all the stuff. Physical hook up of the wires,  learning new software. posting, resizing,  asking questions... days and days turned into weeks.  And I still wasn't even close to anything. It really sucked the fun out of it for me. AND the sweeping sound drove me crazy after 10,000 times. 
I spend a lot of time on the Klipsch forum and those guys will tell you that unless you have a active crossover you will never achieve the right measurments. Not just the bass but to time delay the upper end... its really over whelming.

Most of the time my system sounds lovely....until i open up the computer and start reading forums.   

NO one has been as hepful as you @Anand when dealing with this. I'm still grateful.  Thanks!

[poseidonsvoice]

guf,

I was at Burning Amp just recently, I should have visited you! My parents live in San Jose.

Yes, of course I have a Behringer DCX or you can use a Minidsp or equivalent for the subs. I do not use any active crossover on the mains however, only for the subs. It takes time, but one of my colleagues who has GR Research NX Otica with a pair of Triple 12 OB Rythmik subs along with (2) other sealed 15 inch subs achieved excellent results as well and he was pretty much an REW noob. He is retired, so he had some extra time. I did help him through Facetime, and we are now close colleagues. The time and learning curve is the reason why Duke LeJeune's SWARM setup for most fellas is a bargain! He'll do it for you.

Thanks for the compliments.

Best,
Anand.

[nickd]

nickd, you already have servo subs built into your main speakers. You can just add a pair to the back of the room and you're done.

And did you ever get those speakers built out and playing yet?

I have a gut feeling that those will be very good.

Danny,
Q4 for my company is crazy. Haven’t had time to finish them. Will likely build the extra 3 subs at the same time after December.

Borrowed some speakers with powered subs to get me through the holidays so although I’m anxious to hear the     Hot rodded Elipticor III’s, I have to wait a bit.

[poseidonsvoice]

Nick,

Cool speakers.

Here are the waterfalls, and low frequency spectrograms. They both tell the same thing. Bass basically decays quickly and cleanly, with little to no ringing whatsoever, except below 35Hz in my case (where you want some ringing for HT effects!). Midbass etc...is clean.





Best,
Anand.

[Early B.]

Early B,

Thanks for the complement, but honestly on this forum there is very little if any interest in achieving bass perfection through REW and measurements. Everybody wants one stop shopping and the easy way out!

Yeah, you're right. We're audiophiles, not sound engineers. Learning to take measurements at the level you're talking about seems exhausting and antithetical to the goal which is to sit back and enjoy the music. 

Besides, most of us don't control our audio space -- we share it with wives, kids, friends, etc. So whenever someone, for example, tells me to get some room treatment, I just shake my head. I think the best approach and question for most of us is -- "Based on my situation (budget, room size, WAF, time, etc.), how can I achieve the best possible sound?"