[Jstower]

Some VMPS speakers used drivers made by MISCO, maybe Brian used their drivers for the VLA too. I did not see any passive radiators on their website. Contact them, I read they are nice people.
https://www.miscospeakers.com/

VMPS's passive radiators used a unique high-compliance suspension and a low moving mass diaphragm to achieve a low resonant frequency. The low mass of the passive radiator cone also meant it was very sensitive to small changes to the amount of putty (mass) on the cone.

Thanks WGH, I have owned many VMPS speakers since the 80's, and all of them have had Passive Radiators in them. Brian used the make his own PR. Yes he did use Misco drivers in his speakers. Jim

[WGH]

Look guys the design is proven. VLA subs exist.

I appreciate  everyone's comments, concerns and suggestions, but it just a couple hundred $$ in MDF, really not a big deal. If it sounds terrible, I can always add solid dividers between each sub or just cut the cabinet in half. Jim

Do you have the design? Or is it build a box, stick in 4 speakers and 2 passive radiators and you have a VLA? If it was this easy everyone would do it. Sounds like you are willing to experiment, this project seems more like a VLA clone proof of concept with the realization that the first prototype will not work as expected but may have potential. At first, I would build only one.

When I first started my woodworking business I had a shop partner, his name was Jim too. Sometimes we did jobs together, other times we had our own customers. Jim would get frustrated at me because I drew out designs, made cut lists, researched and ordered hardware before starting a job. Jim thought all that was a waste of time, he really wanted to start cutting and figure it out along the way. Needless to say when Jim worked on his own projects they all became disasters and kludges as he cut stuff apart and reassembled, eventually taking more time than if he worked out all the details beforehand.

[Jstower]

Do you have the design? Or is it build a box, stick in 4 speakers and 2 passive radiators and you have a VLA? If it was this easy everyone would do it. Sounds like you are willing to experiment, this project seems more like a VLA clone proof of concept with the realization that the first prototype will not work as expected but may have potential. At first, I would build only one.

  I have a cut list on my desk. Most DIY people start with a plan and then end up with something else in the end. That's called innovation.  WGH how many speakers have you owned? Unless you are able to have a in home audition of potential speakers, its pretty much a crap shoot.     Just look in the ads here on AC. I've seen many people live with a pair of speakers 6 months then sell and move on to the greatest and latest designs. Jim

[WGH]

WGH how many speakers have you owned? Unless you are able to have a in home audition of potential speakers, its pretty much a crap shoot.

Not too many, I go with the classics and keep them forever. I have been to RMAF many times which is how I discovered Salk speakers.

The first pair were home made cabinets with a single driver 8" speaker with a whizzer cone, the amp was the classic Heathkit AA-14 with the walnut veneer cabinet, about $70 in 1967, that was a lot of money at the time. The sound of the speaker was a disappointment. People are still buying the exact same single driver speaker design 53 years later and whenever I hear one it is still a disappointment.

KLH 17's were the next pair, followed by...

JBL L100 I bought in 1972, heavily modified/braced, cabinet back in now 1-1/2" thick, better crossover parts resulting in tighter bass although they still only go down to 40 Hz before rolling off quickly. Still used daily as shop speakers.

Von Schweikert VR2 speakers bought in 2006 - heavily modified and braced. Mod documentation starts here:
Part 2 - https://www.audiocircle.com/index.php?topic=44748.msg400398#msg400398
Part 3 - https://www.audiocircle.com/index.php?topic=72808.msg683847#msg683847

Salk Sound Veracity HT2-TL bought  in 2011, modified with 1/8" custom mesquite veneer over 1" MDF, 1-3/4" solid mesquite front baffle, constrained layer damping using 2 layers self-stick floor tile with 1" open cell foam on inside walls.
Build photos: https://www.audiocircle.com/index.php?topic=100672.msg1015847#msg1015847

I have opened up my REL Gibraltar G2 sub, it is built like a tank and doesn't need any improvement, the cabinet is only 20"w x 16"h x 24" deep but weighs 84 lbs. 450 AB watts into a single long throw 10" carbon fiber driver. It works very, very well.

Back to your build. Prototypes are fun. I bet you could have a working speaker in 8-20 hours. Quick and dirty. No glue, butt joints with drywall screws, woofers are screwed to the face of the front baffle (not inset), ugly crossover hot wired to speaker cables. More of a proof of concept than finished product. Just build one and measure the response.

When Dennis Murphy is designing a new crossover for Jim Salk he usually has just one speaker in his shop.

[Jstower]

Back to your build. Prototypes are fun. I bet you could have a working speaker in 8-20 hours. Quick and dirty. No glue, butt joints with drywall screws, woofers are screwed to the face of the front baffle (not inset), ugly crossover hot wired to speaker cables. More of a proof of concept than finished product. Just build one and measure the response.

I've moved up, my speakers are all active. The Sub will also be active, I can change crossover setting pretty much on the fly.  Jim

[Housteau]

The VLA can be a bit deceptive when looking straight on.  A 3/4 shot shows their depth.  The cabinet measures 14 inches wide x 19.5 inches deep and stands 68 inches tall.

[Jstower]

I have opened up my REL Gibraltar G2 sub, it is built like a tank and doesn't need any improvement, the cabinet is only 20"w x 16"h x 24" deep but weighs 84 lbs. 450 AB watts into a single long throw 10" carbon fiber driver. It works very, very well.

As far as the REL subwoofers I believe they are great Subwoofer, I'm not discounting your system. But I'm sure if one of these "speakers designers" were to show up at your house to listen to your system, mine system, or anyone on AC, I'm sure they could tweak and improve the sound quality of the system. Jim

[Jstower]

Hello Housteau, WOW those are Beautiful. I bet in person they are breathtaking. Jim

[WGH]

I've moved up, my speakers are all active. The Sub will also be active, I can change crossover setting pretty much on the fly.  Jim

Active subs are super cool, more manufacturers are starting to integrate apps into the plate amp so the crossover and volume can be controlled from a smart phone. The REL Gibraltar line has a remote control wireless puck, an LED display below the driver can show the crossover setting, stereo volume, HT .1 volume and phase, all adjustable on the fly. Turn the bass up on early cool jazz recordings, turn it down on modern pop, all without leaving the sweet spot.

[Jstower]

 I think the only changes to the cabinet with possibly moving one of the 15" passives to the top of the side. The same side or the opposite side I have not decided. Jim

[WGH]

What are the active electronics for your towers? I am always interested how other audiophiles approach the hobby.

Way back in April, 1990 Audio magazine published a detailed article by Ralph E. Gonzalez about the Bassis parametric bass equalizer including circuit board design, parts lists, construction, adjustment and use. I still have that issue. Here is a copy of the article in a pdf file for anyone wanting to build one of these units:
http://wghwoodworking.com/audio/bassis.pdf



Marchand Electronics still makes an assembled Bassis with prices from $690 - $1150
https://www.marchandelec.com/wm8-bass-equalizer.html

While thinking about bass equalization I came across a couple of interesting web sites:

Room and Sub EQ 101: How to use parametric EQ to flatten your bass
http://www.acousticfrontiers.com/2013111room-and-sub-eq-101-how-to-use-parametric-eq-to-flatten-your-html/

Build Your Own Subwoofer by Siegfried Linkwitz which includes design, measurements and equalization
https://www.linkwitzlab.com/thor-intro.htm

[Housteau]

What are the active electronics for your towers? I am always interested how other audiophiles approach the hobby.

I am using the Xilica 4080 active crossover for my system.  It is ideal for my set-up with a wide range of integration options as well as correction for the room.

[ZAKski288]

+1

[ZAKski288]

Hello Jim, back in 2010 or 2011 I went to pick up a couple of mono blocks at a guy’s house somewhere in Michigan, he had a pair of  RM-30’s powered by the amps I came to pick up. A pair of RM-40’s in another room. Also He said he had one VLA subwoofer in his home Theater room in his basement. Never offered to show to me! It’s possible he had one but I really don’t think he did. That’s the closest I came to a Potential VLA sighting.
Good luck with your build Ken

[Speedskater]

Way back then, using active crossovers like Linkwitz designed or the Marchand unit was the way to go. But now crossovers with a DSP processor are much more powerful and often more adjustable.

[WGH]

Are you guys taking measurements and generating EQ filters with the XTZ Room Analyzer II Pro and implementing/importing them into the Xilica XP-4080?



 

[Housteau]

Are you guys taking measurements and generating EQ filters with the XTZ Room Analyzer II Pro and implementing/importing them into the Xilica XP-4080?
 

I use True RTA to plot a real time graph and manually make adjustments where needed.  It is a tri-amped system and so I can be specific on where I make adjustments.

[OldScott]

WGH - Whereas Dave is using the fine Xilica for his V-60s I have been recently using the miniDSP OpenDRC-DA8 which essentially does the same thing. Both of us earlier used Behringers for some time.

Although Brian used to say the Marchand crossovers were top line. for whatever reason he was looking at electronic crossovers for the V-60's. At that time I loaned him an early DEQX to consider. I did not mail it to him in the factory packing but a shipping box from some other componet. Not recognizing it as my DEQX he sat it up on the shelf and forgot about it for 6 months or so but by then he had already decided upon the Behringer. At this time Mike Galusha in Denver had found someone in Holland who was making modification circut boards that greatly enhanced the Behringer. Dave, Brian, and I all ordered one. In fact mine got delayed because Mike had to hurry up Brian's in time for C.E.S. Actually it wasn't C.E.S. for earlier after winning best of show with the RM-40's for some reason Brian got disillusioned with C,E,S. and moved his display to T.H.E.Show which ran concurrently with C.E.S. , usually at the Alexis Park, just off the strip. Mikes modified Behringers had a few quirks. One of them was they you COULD NOT disconnect any interconnects without first turning off the power switch. Dave and I were helping Brian set up the day before the show when somehow in late afternoon  an interconnect got pulled blowing the Behringer. So Brian had to send someone, perhaps John Casler, out in a panic search for one in Vegas. One was found and after that Brian stuck with stock units. That was just as well for it turned out that there was another defect in the circut boards that Mike was being sent which caused them to all  fail after a hundred hours or so operation. Mike later told me that mine was the last to go. So Dave and I used stock Behringers for quite some time after that.

The Behringer is a real enigma. I truly have a love/hate relationship with it  Its functionality is a superb example of really good German engineering putting it at least ten years ahead of its time,. Many parts in it are state of the art BUT many are crap. In the DEQ (which features graphic and parametric EQ in the digital domain) the DAC and ADC chips are high end but distortion is caused by analog conditioning curcuts for which the only solution is to change the circuts completely.The exact same thing is true of the DCX (which provides three way digital crossover). An optimum setup is to use both the DCX and DEQ. Fortunately things work out well if you run the digital output to a good external DAC. Also they can be modified. asi-tek has  a long line of upgrades to include  AADC and DAC replacement, clock upgrade, EMI/RFI shielding,  Bybee Rails, and even an external battery upgrade. I cannot vouch for their services as there are both good and not so good comments on them on the Web. However he whole gamut ot their upgrades cost upwards of $3,000 which seems over reaching for a unit costing only a few hundred dollars and considering available alternatives. A lesser expensive approach is with Behringermods.com in Great Britain. They sell replacement audio circut boards for around $200USD for the DCX and $150USD for the DEQ. For those who might not want to run the risk of killing oneself (or loved ones) with a soldering iron they will do installation on the DCX for $270 and the DEQ for $280. For an outline of the issues with the Behringers, parts, and services see behringermods.com. Whith all this being said I am still keeping my units as a reserve backup in case what I am using fails! 

[OldScott]

OH, being Pro-Audio units input needs to be attenuated by about 15db.

[ZAKski288]

Scott, thanks for the Behringer mods site, very interesting. Has anyone had a unit modded?  Ken