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Audio/Video Gear and Systems => Owner's Circles => VMPS Speakers => Topic started by: John Casler on 11 Jan 2005, 02:35 am

Title: "DIRECT DRIVE" VMPS for DEQX/TACT systems and VMPS
Post by: John Casler on 11 Jan 2005, 02:35 am
Hi All,

While Brian and I feel that the best "intended" sound of the VMPS speaker systems is derived from the "SYSTEM" installed and tuned via Big B's design philosophy, we also recognize that many of you are exploring the new "digital room and speaker correction systems".

In light of this, Brian has agreed to let me "offer" all VMPS Systems with an option to accomadate these new systems.  The initial offerings are listed below:

Option 1 = DIRECT DRIVE VMPS

This system has "NO" crossovers in the system and the binding posts drive direct to the individual drivers.  All binding posts will have the minimum possible wiring direct to drivers.  This can be ordered on all systems.


Option 2 = DIRECT DRIVE and Standard VMPS

This system allows the best of both worlds having both "Direct Drive" and Crossover systems in the speaker.  It will have 2 times the binding posts.

I will have the pricing "firmed up" shortly and will post them both here and in the "price list" sticky.

It is quite evident that "at least part" of digital audio's future is moving in this direction.

VMPS is interested in offering the tools to allow our users to have the options they need to move in the directions they choose and not have to resort to a significant amount of DIY speaker building unless they enjoy that sort of thing.

B, and I had the opportunity to have additional discussion on the future of VMPS and we have some things in store that I think will knock your socks off. :o

I suggested a couple more VERY EXCITING  :bounce: "upgrade/options" that will be tested and hopefully added to the VMPS menu soon.

One new upgrade is for the RM40 woofer system.  The upper bass woofer has been significantly improved, and is now available.  

I had the opportunity to hear the improvement in weight, impact and attack over the last few days in Las Vegas.  The improvement is very nice, and could only be done by someone who designs their bass drivers, as Brian does.


I will explain this in more detail in a seperate post shortly.
Title: "DIRECT DRIVE" VMPS for DEQX/TACT systems and VMPS
Post by: zybar on 11 Jan 2005, 03:04 am
As one of the guys using a Tact preamp with my RM 40's, I am very happy to hear this John.

Please post the details on the woofer upgrade/changes as soon as possible.

George
Title: "DIRECT DRIVE" VMPS for DEQX/TACT systems and VMPS
Post by: ted_b on 11 Jan 2005, 03:38 am
John,
This is the right direction for VMPS to be taking.  Great ideas.

I'm sure my RM/X's cannot be retrofitted, as you described, without significant pain and suffering, but I know Brian supports going in and shorting out the woofer xover.  Is there any possibility that the treble/mid xover can be bypassed in the field?  My DEQX arrived this weekend and I'd love to take full advantage of the flexibility of their crossovers.  
Thx,
Ted_B
Title: "DIRECT DRIVE" VMPS for DEQX/TACT systems and VMPS
Post by: JoshK on 11 Jan 2005, 03:58 am
Ted,

May I suggest you take one step in sucession with the next?  Start with the woofers disaggregated with the rest and then move onto the mid/tweet section.   Before attempting the mid/tweet, can you verify for DEQX/VMPS owners that the DEQX xo can simulate a series first order xo, i.e. a quasi second order?  PM me if you need more details.  I think it can but I am not 100% sure.
Title: "DIRECT DRIVE" VMPS for DEQX/TACT systems and VMPS
Post by: John Casler on 11 Jan 2005, 04:13 am
Quote from: ted_b
John,
This is the right direction for VMPS to be taking.  Great ideas.

I'm sure my RM/X's cannot be retrofitted, as you described, without significant pain and suffering, but I know Brian supports going in and shorting out the woofer xover.  Is there any possibility that the treble/mid xover can be bypassed in the field?  My DEQX arrived this weekend and I'd love to take full advantage of the flexibility of their crossovers.  
Thx,
Ted_B


Hi Ted,

I felt that it was the best way to address the direction some customers and clients were going.  That said, the "magic" that Brian "installs" is the heart of VMPS. but...the exploration of the new technology by you, the users, might allow for additional "growth".

We wish to provide a tool to enjoy your hobby wether it be for the ultimate, analog, digital, audio, or HT system.

To address this, we need to offer a flexibility that will allow us to harvest the maximum performance from many directions.

This is just one of those directions.

As far as "retro-fitting" that is a "technical" conversation you would need to have with Brian.
Title: "DIRECT DRIVE" VMPS for DEQX/TACT systems and VMPS
Post by: John Casler on 11 Jan 2005, 04:20 am
Quote from: zybar
As one of the guys using a Tact preamp with my RM 40's, I am very happy to hear this John.

Please post the details on the woofer upgrade/changes as soon as possible.

George


Hi George,

Well you and a few of the others here, were the impetus to me petitioning Brian with this move.

I have also contacted the local DEQX dealer and worked out a deal where I might be able to put together some "VMPS Digital Drive" packages.

I beleive it can be so optioned on all of the line.

I would ask that all of you who have success with the two technologies, share some of the details so new comers can profit from your "early adaptor" status. :mrgreen:

As far as the woofer upgrade for the RM40, I will post that in another post soon.
Title: "DIRECT DRIVE" VMPS for DEQX/TACT systems and VMPS
Post by: ekovalsky on 11 Jan 2005, 04:43 am
Quote
VMPS is interested in offering the tools to allow our users to have the options they need to move in the directions they choose and not have to resort to a significant amount of DIY speaker building unless they enjoy that sort of thing.


Glad to hear it, since I've been contemplating an ultra-ambiltious DIY system to replace the RM/X since going "digital".  

I have taken the first step and already and am using the 2.2X subwoofer outputs to driver the RM/X woofers (with the inductor coil bypassed) and the main outputs to drive the mid/tweeter (through the factory crossover).  The improvement just by actively biamping, with room correction bypassed, is substantial.  Best sound  (supported by measurements) is with the TacT applying a 24db/octave low pass filter to the woofers at 300hz and a 36db/octave high pass filter to the ribbons at 220hz.  A slight delay is also added to time align the bass to the mid/treble.  An audiophile who came for an audition greatly preferred this TacT RCS/S2150 setup, in bypass mode, to the much more expensive JRDG 302/4 used in a passive biamp configuration.

Correction definitely takes the speakers to the next level.  Room correction works predominantly in the bass, but an even bigger improvement results from what essentially is speaker correction of the midrange and treble.   Of course the TacT doesn't offer proper speaker correction, as it corrects the combined room and driver anomalies as measured at the listening position.    In the sweet spot the sound is phenomenal, but the pre-distorted output is very evident elsewhere in the room.  DEQX does not have this limitation and would probably work better than the TacT.

I've pestered Brian about embracing new technology for a few years, dating back to when I requested three extra sets of binding posts for my (currently TDangelo's) RM-40.  There is no doubt in my mind that this is the way of the future.  The best mathematical modelling and parts selection cannot compare with measurements made in the owner's listening room with computer analysis and infinite DSP flexibility.  Full control over group delay, phase, and frequency response will raise any loudspeaker's performance to another level.

It is not surprising that loudspeaker producers are somewhat avoidant of this new technology.  The "secret" crossover circuits each produces and markets is what gives their product personality and prevents it from being easily replicated by the DIY crowd.  Build a big box with an Aurum Cantus G2si tweeter, four Monsoon ribbons sourced from computer speakers bought cheap off Ebay, and some 10" Eminence woofers and a passive radiator.  You've made a ghetto RM-40 that would probably perform very well with a DEQX and some decent amps.

Anyway I am very glad Brian is now willing to head down this path.  I look forward to seeing what new products will come to market, and hopefully existing customers will not be forgotten.
Title: "DIRECT DRIVE" VMPS for DEQX/TACT systems and VMPS
Post by: PLMONROE on 13 Jan 2005, 04:03 am
Ekovalsky,  obviously I have been laboring under a misundestanding. I thought that the TacT and DEQX  both worked about the same. You said that the TacT corrects for both speaker and room anomalies (I thought both did) and the DEQX doesn't? Are you saying that  the DEQX can correct for one or the other or maybe both somehow?

Paul
Title: "DIRECT DRIVE" VMPS for DEQX/TACT systems and VMPS
Post by: ekovalsky on 13 Jan 2005, 04:39 am
Quote from: PLMONROE
Ekovalsky,  obviously I have been laboring under a misundestanding. I thought that the TacT and DEQX  both worked about the same. You said that the TacT corrects for both speaker and room anomalies (I thought both did) and the DEQX doesn't? Are you saying that  the DEQX can correct for one or the other or maybe both somehow?

Paul


The DEQX offers independent room correction and driver correction.  So you can use it to flatten frequency response of the drivers without room correction.  

The TacT technically offers only room correction.  However, in calculating the correction filter it uses measured response at the mic position which obviously reflects anomalies from the room and drivers combined.  What the TacT cannot do is correct the drivers only.  

So of the two the DEQX is the more flexible, and it seems to overall have a better user interface.  But the TacT integrates very nicely with the S2150 amps and has a reasonable amount of control available from the remote and front panel display, without the computer hooked up.
Title: "DIRECT DRIVE" VMPS for DEQX/TACT systems and VMPS
Post by: mac on 13 Jan 2005, 05:04 am
Quote from: JoshK
Before attempting the mid/tweet, can you verify for DEQX/VMPS owners that the DEQX xo can simulate a series first order xo, i.e. a quasi second order?  PM me if you need more details.  I think it can but I am not 100% sure.


The PDC 2.6 is capable of implementing Linear-Phase, Linkwitz-Riley and Butterworth filters from 1st to 300th order.  While one could certainly emulate the stock crossover of the speaker using low-order slopes (and that's probably a good place to start), most people who ultimately use the unit will end up using high-order Linear-Phase filters (IMO).

Linear-Phase:
(http://lowfat.sytes.net/~mike/deqx/DEQX_linear.jpg)

Linkwitz-Riley:
(http://lowfat.sytes.net/~mike/deqx/DEQX_LR.jpg)

Butterworth:
(http://lowfat.sytes.net/~mike/deqx/DEQX_butter.jpg)
Title: "DIRECT DRIVE" VMPS for DEQX/TACT systems and VMPS
Post by: ekovalsky on 13 Jan 2005, 05:33 am
One thing to add about my previous post...

To get best sound at the listening position (i.e. limited sweet spot) the TacT works great.  The correction filter normalizes room effects and driver aberrations, so the signal at the listening position will equal the target curve.  I have two chairs in the "sweet spot", one just to the left and the other just to the right of the room midline.  I have saved a different correction curve for each chair.  When the appropriate curve is selected imaging is phenomenal with a wide and deep soundstage and precise vocals floating in the center.  Amazing!

However, when listening in a position away from the sweet spot where measurements were made for the correction filter, things get ugly.  Sound is better with room correction turned off, but then the non-flat frequency response of the drivers becomes very noticeable.  After hearing the improvements from room/driver correction it is hard to go back!

The big advantage of the DEQX is that, when away from the sweet spot, room correction can be turned off but driver correction is still applied.  

Main benefit of room correction is in the bass, 300hz and below.  The new Meridian gear only works in this range.  Although I had never realized it, before getting the TacT I was missing lots of bass information either because of room suck outs or strong nodes obscuring adjacent frequencies.  With room correction the bass just sounds right!

Driver correction smooths frequency response of the midrange and tweeters.  I was very surprised how non-flat the measurements were from 500hz on up .  

This new equipment has really changed my thoughts on high end audio.  The changes from different cables, source components, power conditions, etc now seem like a joke.
Title: "DIRECT DRIVE" VMPS for DEQX/TACT systems and VMPS
Post by: ted_b on 13 Jan 2005, 05:50 am
Eric,
Is the room correction in the Tact aggresively going after the higher frequencies so as to truly give you a flat target?.  In the DEQX you can manually do it, but Auto EQ only addresses 500hz and down, and realistically 300hz and down, the real gremlins in room response.  When I try to get rid of the treble troughs the system sounds a bit bright.  Realize, though, that I haven't done any speaker correction yet.  That's where a lot of that gets fixed...Anyway, was interested in what your RM/X's sound like with gain filters in the higher regions.

Ted_B
Title: "DIRECT DRIVE" VMPS for DEQX/TACT systems and VMPS
Post by: ekovalsky on 13 Jan 2005, 06:08 am
Quote from: ted_b
Eric,
Is the room correction in the Tact aggresively going after the higher frequencies so as to truly give you a flat target?.  In the DEQX you can manually do it, but Auto EQ only addresses 500hz and down, and realistically 300hz and down, the real gremlins in room response.  When I try to get rid of the treble troughs the system sounds a bit bright.  Realize, though, that I haven't done any speaker correction yet.  That's where a lot of that gets fixed...Anyway, was interested in what your RM/X's sound like with gain filters in the higher regions.

Ted_B


I think you will be shocked at the improvement that driver correction makes .  As impressive as the room corrections is for the bass, flattening the midrange and treble response made an even greater difference is sound quality.

On your measurements, you will probably notice a broad, strong peak at around 1.2khz with flanking dips.  Neutralizing this greatly improved the midrange, and with correction off the midrange sounds way too heavy and the presentation far too forward.  Never noticed this before the TacT  :oops:

You will definitely not want to correct the tweeter output to "flat" -- if you do it will be far too bright.   Instead you want a roll off in the treble.  I have mine -3dB at 10khz and about -dB at 20khz.  All the TacT stock curves show a similar roll off, hopefully the DEQX curves do also.

I also noticed a dramatic improvement in imaging with correction of mid and high frequencies.  A lot of this is related to phase and lobing effects that occur off axis.  With correction on the soundstange is huge front to back, left to right.  On good classical recordings each instrument has its own discernable space.  Vocals float precisely in the dead center.  Speakers totally disappear -- pretty amazing given the imposing size of the RM/X.  When correction is bypassed this wonderful imaging diffuses into a wall of sound clearing coming from two big speakers.  Again, I thought imaging was really good before I got the TacT   :oops:

Sadly, I don't think I'll ever be able to enjoy a high end system without correction.  Once you cross this bridge there is no going back.
Title: "DIRECT DRIVE" VMPS for DEQX/TACT systems and VMPS
Post by: angelo on 13 Jan 2005, 06:48 am
what if the passive crossover of the speakers CAN"T be bypassed (4-way full range bi-ampable floorstander), I know that because of this I can't implement the full potential of DEQX, but can I still use the active crossover to control what frequencies goes to each pair of binding post?

which frequency band will need a higher quality amp, high frequencies or mids?

thanks,

angelo
Title: "DIRECT DRIVE" VMPS for DEQX/TACT systems and VMPS
Post by: Jose R. on 13 Jan 2005, 07:03 am
Quote from: ekovalsky
The TacT technically offers only room correction.  However, in calculating the correction filter it uses measured response at the mic position which obviously reflects anomalies from the room and drivers combined.  What the TacT cannot do is correct the drivers only.  

So of the two the DEQX is the more flexible, and it seems to overall have a b ...


If one uses the Tact 2150 amps together with the room correction, one can perform speaker correction as well.  One would take a measurement of individual speakers and/or drivers, apply crossover and correction, ad then remeasure the integrated system with final room correction being carried out by the RCS.

I have been playing around with this for a while now with my RM30's with good results.  I have just received the megawoofer and Auric Cap upgrade and am busy installing this.  I will add separate binding posts connected directly to the different drivers to permit full digital crossover implementation but am short of one amp which I would need for the tweeter.

As has been mentioned, once one is used to listening to corrected sound, there is no going back... :D

Regards

Jose
Title: "DIRECT DRIVE" VMPS for DEQX/TACT systems and VMPS
Post by: woodsyi on 13 Jan 2005, 01:44 pm
Ted and Eric,

Thanks for much information on this issue.  As one who is actively biamping a pair of RM40s with 200Hz ribbon hp and 300Hz woofer lp using 24dB slopeand driven by tubes on top and ss on the bottom, I have a couple of questions for you.   Have you tried an anolog source?  Is the gain in digital crosssover flexibility greater than what may be lost in ADC/DAC cycle?  Have you driven the ribbons with tube amp and how well does either DEQX or DACT work with tubes?  

I ask because I am intrigued by the flexibility of digital crossover but I am concerned about losing the richness of anolog sound from tubes.  The biggest gripe I have with a middle of the road digital source is the lack of harmonic fulness in the mid region.  I am concerned that digitizing of anologue source would rob its soul.  Any comments?
Title: "DIRECT DRIVE" VMPS for DEQX/TACT systems and VMPS
Post by: ted_b on 13 Jan 2005, 02:18 pm
Woodsyi,
The analog issue was my greatest concern in going this direction (with the DEQX).  As I've only had the pre for 4 days so far, and only done some room correction (no xovers, single amp so far) I don't have an answer yet about analog.  The 24/48 DACS sound good (a 24/96 no cost software upgrade is in development, as per Kim's comments in the 6moons review).  The unbalanced analog ins on my pre are too sensitive (clipping inputs) but DEQX support provided me the instructions to set a couple of jumpers to change the input sensitivity.  DEQX support has been great, and it doesn't hurt at all that their Sydney work schedule meshes nicely with my East Coast nightime listening schedule.  As soon as I find an anti-static strap around here I'm fixing the analog ins.

So, I empathize with you.  I've spent quite a bit of time and money getting a beautiful analog sound out of my Modwright 999ES tubed output, and my tubed pre was a nice match.  SACD's and DVD-A's are essential parts of my collection.  However, early results are telling me that the smoothness of the room response, coupled with upcoming speaker correction (my upcoming, not theirs)  and active crossover flexibility will more than offset a da/ad/da journey.

Haven't tried tube amps.

Ted_B
Title: "DIRECT DRIVE" VMPS for DEQX/TACT systems and VMPS
Post by: woodsyi on 13 Jan 2005, 03:03 pm
Ted,
I am anxious for you to get your anolog connection fixed and report back on the sound.  I don't suppose DACT would have the same issue since they make attenuators.  I am curious about the bypass mode.  Do you still get digital crossover function while an anolog source (i.e. signal from phono pre) is played through an anolog input?  It would be great if this is true.  I can play my vinyl via bypass (avoiding ADC) but still get digital crossover with its inherent advantage over active anolog or passive crossovers.
Title: "DIRECT DRIVE" VMPS for DEQX/TACT systems and VMPS
Post by: ted_b on 13 Jan 2005, 03:14 pm
Bypass in DEQX world is still digital, it just bypasses the room correction filters.  Any speaker correction is done before the bypass.  I need to understand more about the diff between their analog volume and digital volume, though.  An analog volume button is new in the 1.4.1 software and I need to understand its relevance.

Ted_B
Title: "DIRECT DRIVE" VMPS for DEQX/TACT systems and VMPS
Post by: woodsyi on 13 Jan 2005, 03:29 pm
I guess I should know better than that -- digital crossover by definition would require a source music to be digitized.     Doh! :oops:
Title: "DIRECT DRIVE" VMPS for DEQX/TACT systems and VMPS
Post by: ekovalsky on 13 Jan 2005, 04:16 pm
Woodsyi,

I have no analog source.  Based on the perceived improvement in the sound with correction on, I will confidently say any digitization loss will be far outweighed by the benefits of DSP.  

The gain of the TacT ADC module is adjustable via the remote control and main display on the chassis.  You do not need to change jumpers or configure via software.
Title: "DIRECT DRIVE" VMPS for DEQX/TACT systems and VMPS
Post by: ctviggen on 13 Jan 2005, 04:38 pm
You've just shocked those in the Vinyl circle.  ;-)
Title: "DIRECT DRIVE" VMPS for DEQX/TACT systems and VMPS
Post by: brj on 14 Jan 2005, 04:36 am
Eric, I've read your comments with great interest.  Would the following statements form an accurate summary?

1) Driver correction improves the sound everywhere in the room (both inside the sweet spot and outside the sweet spot).

2) Room correction improves the sound inside the sweet spot, but degrades the sound outside the sweet spot.

Assuming that I didn't distort or over-simplify your comments, I'm curious about the size of the sweet spot itself when using active correction.  Does the activation of driver correction or room correction, alone or in tandem, affect the size of the sweet spot?

Many thanks!
Title: "DIRECT DRIVE" VMPS for DEQX/TACT systems and VMPS
Post by: ekovalsky on 14 Jan 2005, 05:05 am
Quote from: brj
Eric, I've read your comments with great interest.  Would the following statements form an accurate summary?

1) Driver correction improves the sound everywhere in the room (both inside the sweet spot and outside the sweet spot).

2) Room correction improves the sound inside the sweet spot, but degrades the sound outside the sweet spot.

Assuming that I didn't distort or over-simplify your comments, I'm curious about the size of the sweet spot itself when using active correction.  Does the activation  ...


Very accurate!  Glad someone could understand the gibberish that I write  :o

With TacT's combined room/speaker correction, the sweet spot is wonderful but small -- about the width of one chair.  Moving a little outside that range doesn't degrade things too much but the beautiful floating center image begins to shift and diffuse.  Further out, particularly closer to the speakers, distortion of the signal becomes quite evident as the correction filter is applying signal cuts and boosts detrimental to the particular nodes at that position.

As I hinted in an earlier post, the small sweet spot does have its advantages.  In my case I can enjoy perfect imaging from either listening chair (one closer to the left speaker, other closer to the right speaker) by switching correction presets.  In addition to optimizing the correction filter for each sweet spot, the TacT also accounts for the time delay from the further speaker (by delaying the signal to the closer speaker) and equalizes channel balance when listening off center.  Very neat!
Title: "DIRECT DRIVE" VMPS for DEQX/TACT systems and VMPS
Post by: John Casler on 14 Jan 2005, 05:14 am
Quote from: ekovalsky
Very accurate!  Glad someone could understand the gibberish that I write  :o

With TacT's combined room/speaker correction, the sweet spot is wonderful but small -- about the width of one chair.  Moving a little outside that range doesn't degrade things too much but the beautiful floating center image begins to shift and diffuse.  Further out, particularly closer to the speakers, distortion of the signal becomes quite evident as the correction filter is applying signal cuts and boosts detrimental to the  ...


We are currently working on a GPS guidance system that will guide the digital processing system to adjust the sweet spot to your movement in the room.  

With this process, no matter where you are in the room the soundstage and imaging, as well as total frequency and phase response will adjust to that movement.


 :roll:  :roll:  :roll:  :wink:  :wink:  :wink:  :lol:  :lol:  :lol:

I trust everyone sees where this is going.  While I , of course am jesting, this type of cross pollination of technologies is what I can see, not too far down the road.

And it doesn't really have to be GPS, it could simply be a series of motion sensors in specific locations within the room.

If I didn't already have 5 patents, I'd be writing a provisional right now. :mrgreen:
Title: "DIRECT DRIVE" VMPS for DEQX/TACT systems and VMPS
Post by: brj on 14 Jan 2005, 01:04 pm
Quote from: ekovalsky
Very accurate! Glad someone could understand the gibberish that I write icon_eek.gif

It only took a few codebreakers to figure it out! :lol:


Quote from: ekovalsky
With TacT's combined room/speaker correction, the sweet spot is wonderful but small -- about the width of one chair. Moving a little outside that range doesn't degrade things too much but the beautiful floating center image begins to shift and diffuse. Further out, particularly closer to the speakers, distortion of the signal becomes quite evident as the correction filter is applying signal cuts and boosts detrimental to the particular nodes at that position.

And what about the DEQ/X with driver correction only?  Regardless of how the system sounds in the rest of the room, is that sweet spot larger?

(Presumably, it wouldn't be as accurate as the TacT in the sweet spot, since the room correction would be off, but this might be a beneficial sacrifice for those times when the system is pressed into HT duty and has to serve a larger audience.  Then, for critical listening - which tends to be done alone or with one or two other people - you can re-engage the room correction.)


Quote from: ekovalsky
As I hinted in an earlier post, the small sweet spot does have its advantages.

Ah, but I want it all!  Pin-point imaging and a sweet spot measured in miles!   Or, if John gets really creative, the ability to GPS track and aim the perfect image at multiple people simultaneously from a single pair of speakers! :D

Thanks again for the pointers!
Title: "DIRECT DRIVE" VMPS for DEQX/TACT systems and VMPS
Post by: ctviggen on 14 Jan 2005, 01:44 pm
Does the TACT allow you to turn these on and off?  For instance, correct the speaker when you have a bunch of people in the room, and correct the room when you're listening in stereo?
Title: "DIRECT DRIVE" VMPS for DEQX/TACT systems and VMPS
Post by: Jose R. on 14 Jan 2005, 05:26 pm
Quote from: ctviggen
Does the TACT allow you to turn these on and off?  For instance, correct the speaker when you have a bunch of people in the room, and correct the room when you're listening in stereo?


The Tact system is very flexible with 9 presets in the RCS module plus a bypass option as well as 5-10 options (depending on filters used) in the amps.
You can save different measurments to different presets and choose which one you want to use.

Regards

Jose
Title: "DIRECT DRIVE" VMPS for DEQX/TACT systems and VMPS
Post by: doug s. on 14 Jan 2005, 08:32 pm
i wonder if you could do driver correction w/the tact, by placing your speakers outdoors...

doug s.
Title: "DIRECT DRIVE" VMPS for DEQX/TACT systems and VMPS
Post by: Jose R. on 15 Jan 2005, 06:35 am
Quote from: doug s.
i wonder if you could do driver correction w/the tact, by placing your speakers outdoors...

doug s.


Hi Doug

Technically I guess you could but do not know whether it would result in overall better results.  Some users have taken measurements 3-4' from the speakers for "speaker correction" purposes.
I have used measurements taken at the listening position which obviously includes the room contribution.  I have found that when doing final measurements for room correction, the contribution of "speaker correction" is very visible with a flatter response.
Note however that with speaker corection one can only correct for peaks - digital filters cannot go above 0dB.  You thus lose some gain and need to use higher Tact output pulses to achieve the same gain.  The benefit is that the final room correction does not require as much correction thus gain loss is reduced.  What I am trying to say is that final listening volume is not much different using speaker correction plus room correction vs only room correction.
Another point - one must be careful about the different delays induced by different digital filters and one must always measure each driver so that time delays are equal for all the drivers - it is a bit time consuming but well worth it.

Regards

Jose
Title: "DIRECT DRIVE" VMPS for DEQX/TACT systems and VMPS
Post by: ctviggen on 15 Jan 2005, 12:01 pm
From what I understand from reading this thread, the TACT only performs room correction, while the DEQ/X allows you to perform both speaker and room correction.  Is that correct?  Why would one choose a TACT over a DEQ/X or vice versa?
Title: "DIRECT DRIVE" VMPS for DEQX/TACT systems and VMPS
Post by: Jose R. on 15 Jan 2005, 03:25 pm
Quote from: ctviggen
From what I understand from reading this thread, the TACT only performs room correction, while the DEQ/X allows you to perform both speaker and room correction.  Is that correct?  Why would one choose a TACT over a DEQ/X or vice versa?


Bob,

The correction performed by Tact RCS is in reality a combination of speaker and room correction.  I have no experience or knowledge of the DEQX so cannot say how it differs from the Tact in practice.

Regards

Jose
Title: "DIRECT DRIVE" VMPS for DEQX/TACT systems and VMPS
Post by: cinema&sound on 15 Jan 2005, 08:20 pm
I have been following this with some interest as we have some audio analysis equipment, but have not yet used any DSP technology to correct.

We have used traditional correction methods like acoustic treatments, moving furniture. Even changing room dimensions to move modal anomalies to places where people aren't.

My question is:
Are TACT etc. correction systems appropriate for surround sound also? Nothing to detract from 2 channel systems, but my customer’s world is primarily surround. This is primarily movies, but also SACD and DVD audio.

Thanks
Scott
Title: "DIRECT DRIVE" VMPS for DEQX/TACT systems and VMPS
Post by: Jose R. on 15 Jan 2005, 10:04 pm
Quote from: cinema&sound
IMy question is:
Are TACT etc. correction systems appropriate for surround sound also? Nothing to detract from 2 channel systems, but my customer’s world is primarily surround. This is primarily movies, but also SACD and DVD audio.

Thanks
Scott


Hi Scott

Tact has a 10 channel theatre correction system (TCS) which would do what you require (ie stereo and multichannel).  I have not heard or used it but it is apparently very good.  For DVD-Audio and SACD you would however require an additional A/D module.
You can get more info at www.tactlabs.com

Regards

Jose
Title: "DIRECT DRIVE" VMPS for DEQX/TACT systems and VMPS
Post by: KJ on 23 Jan 2005, 06:31 pm
Getting back to the original topic:

Quote from: John Casler
This system allows the best of both worlds having both "Direct Drive" and Crossover systems in the speaker. It will have 2 times the binding posts.

How do you disconnect the passive crossover when you want to use an active crossover with the direct drive posts?

Quote from: John Casler
I will have the pricing "firmed up" shortly and will post them both here and in the "price list" sticky.

Any update?

-KJ
Title: "DIRECT DRIVE" VMPS for DEQX/TACT systems and VMPS
Post by: John Casler on 23 Jan 2005, 07:08 pm
Quote from: KJ
Getting back to the original topic:

Quote from: John Casler
This system allows the best of both worlds having both "Direct Drive" and Crossover systems in the speaker. It will have 2 times the binding posts.

How do you disconnect the passive crossover when you want to use an active crossover with the direct drive posts?

Quote from: John Casler
I will have the pricing "firmed up" shortly and will post them both here and in the "price list" sticky.

Any update?

-KJ


Hi KJ,

My understanding is that you simply connect to the Direct Drive set of Binding posts, but there may need to be a "disconnect" of some type.

I will post pricing as soon as we have a few things firmed up.  I have been in contact with DEQX regarding the best implementation and "system or package" pricing.



I also have a couple other "proprietary" applications to discuss with them which will clearly offer HUGE benefits in a couple specific areas.

In fact, if I am correct, it may make a huge difference in a MAIN performance area!!

I will post pricing to the price list as soon as it is firmed up.
Title: "DIRECT DRIVE" VMPS for DEQX/TACT systems and VMPS
Post by: brj on 27 Jan 2005, 10:10 pm
I guess I'm a bit confused as to the exact implementation details, specifically:

1) Will the "direct drive" option use 4 pairs of binding posts?  (Tweeters, mid-range panels, mid-bass woofers, and low bass woofers)

2) Will the "direct drive plus" option include 6 pairs of binding posts?  (The 4 direct drive pairs described above plus the traditional 2 pair for the bi-ampable passive crossover.)

3) For the "direct drive plus" option, will there be a mechanism to fully disconnect the passive crossover when the "direct drive" binding posts are in use?

Many thanks for the clarification!
Title: "DIRECT DRIVE" VMPS for DEQX/TACT systems and VMPS
Post by: KJ on 28 Jan 2005, 04:51 pm
jimmyp58 has confirmed there are three extra sets of binding posts added for Option 2 (DD & S VMPS).  Thanks Jim!

Quote from: brj
3) For the "direct drive plus" option, will there be a mechanism to fully disconnect the passive crossover when the "direct drive" binding posts are in use?

Still hoping Brian C. can answer to this one.  Assuming there is no manual disconnect and one uses the DD binding posts, wouldn't the signal/current bleed back to the passive crossover?

I'm currently not interested in pursuing an all-digital setup.  However, assuming DD&SV doesn't cause any issues this option is appealing in the event digital becomes the wave of the future.

-KJ
Title: "DIRECT DRIVE" VMPS for DEQX/TACT systems and VMPS
Post by: Jose R. on 28 Jan 2005, 09:14 pm
Quote from: KJ
Still hoping Brian C. can answer to this one.  Assuming there is no manual disconnect and one uses the DD binding posts, wouldn't the signal/current bleed back to the passive crossover?
-KJ


I would be intersted to know what effect the passive components would have.  I have created separate binding posts for each driver but as I see it, the inductors will still be in the circuit even when connecting the digital amps direct to the drivers.  I wonder whether this has any effect?

Jose
Title: "DIRECT DRIVE" VMPS for DEQX/TACT systems and VMPS
Post by: John Casler on 28 Jan 2005, 09:30 pm
Quote from: brj
I guess I'm a bit confused as to the exact implementation details, specifically:

1) Will the "direct drive" option use 4 pairs of binding posts?  (Tweeters, mid-range panels, mid-bass woofers, and low bass woofers)

2) Will the "direct drive plus" option include 6 pairs of binding posts?  (The 4 direct drive pairs described above plus the traditional 2 pair for the bi-ampable passive crossover.)

3) For the "direct drive plus" option, will there be a mechanism to fully disconnect the passive crossove ...


1) Direct Drive can have a pair of binding posts for each Driver System

For example: the RM30M can have up to 4 pair.  I'll have to check with brian but I think the RM40 will have 3 pair since the upper and lower woofer work together.  The 626R would have 3 pair.

I think the majority of DSP users will be ordering the RM30C and mating it with a seperate SubWoofer system, which would mean 3 pair on the RM30C.

I don't know the x-over limits of all the current DSP systems, but I assume there are provisions for 3-4 way speakers or speakers plus subs. DIRECT DRIVE can be ordered accordingly.

2) Depends on which DSP system you select and how you wish to configure your drivers.

3) B, told me no disconnect device is required, the way he will wire it.

Ordering these combinations will require attention to detail.
Title: "DIRECT DRIVE" VMPS for DEQX/TACT systems and VMPS
Post by: KJ on 28 Jan 2005, 09:51 pm
Quote from: John Casler
B, told me no disconnect device is required, the way he will wire it.

Does this mean there is a way to wire it into the system without having the current pass back through the passive crossover?

-KJ
Title: "DIRECT DRIVE" VMPS for DEQX/TACT systems and VMPS
Post by: John Casler on 28 Jan 2005, 10:31 pm
Quote from: KJ
Quote from: John Casler
B, told me no disconnect device is required, the way he will wire it.

Does this mean there is a way to wire it into the system without having the current pass back through the passive crossover?

-KJ


I assume it means that it is not a concern the way it is wired.
Title: "DIRECT DRIVE" VMPS for DEQX/TACT systems and VMPS
Post by: Jose R. on 29 Jan 2005, 08:58 am
[quote="KJDoes this mean there is a way to wire it into the system without having the current pass back through the passive crossover?
-KJ[/quote]

I have been thinking about this and now realize that the way I have wired my direct connection to the individual drivers does not eliminate the passive crossovers completely.  What effect they will have is unclear as this will be determined by the resistance of the passive components vs the drivers themselves.
This perhaps explains my measurements of the direct connections vs those via the passive crossovers where the lower end roll-off of the panels for example was quite similar in the two measurements.  This could be that the passive crossover was still in the circuit (in parallel with the link between pos and neg being the inductor).
The only way I can see to overcome this and get a true direct connection is to interrupt one of the legs between the passive components and drivers, pos or neg, connect two wires to each cut end and bring these wires out of the cabinet.  These wires could be joined to complete the circuit and allow use of the passive crossover or separated, allowing direct connections to the drivers using separate binding posts.  Three sets of wires would thus have to be created (for the RM30C) and while it may not look fancy, it would do the trick.

Jose
Title: "DIRECT DRIVE" VMPS for DEQX/TACT systems and VMPS
Post by: PLMONROE on 30 Apr 2005, 04:28 am
Is there a practical way to use eiher the TacT or DEQX  for room equalilzation in a trinaural setup, short of buying two units???
Title: "DIRECT DRIVE" VMPS for DEQX/TACT systems and VMPS
Post by: ekovalsky on 30 Apr 2005, 04:49 am
Quote from: PLMONROE
Is there a practical way to use eiher the TacT or DEQX  for room equalilzation in a trinaural setup, short of buying two units???


TacT TCS mk2 will probably do the trick but it is expensive.
Title: "DIRECT DRIVE" VMPS for DEQX/TACT systems and VMPS
Post by: John Casler on 30 Apr 2005, 04:45 pm
Quote from: PLMONROE
Is there a practical way to use eiher the TacT or DEQX  for room equalilzation in a trinaural setup, short of buying two units???


Hi Paul,

Interesting question.  If the TACT or DEQX can provide the "room equalization" circuitry to the 2 channel outputs "full range" only, then that could be fed to the TriNaural.

The TriNaural would then be able to "triangulate" :lol:  the "equalized signal over the three speakers, or three speakers and a SUB.

Not knowing if the TACT or DEQX "can" output the "room equalized" signal full range into only 2 channel outs is the question.

If it can do the two channel thing, then obviously the whole room equalization process, would have to take place with the TriNaural in the system during the set up.

It would also mean sacrificing the "speaker equalization/correction" processes, since they rely on more outputs.

If the "room equalization" program and "output" cannot be directed through the 2 channel line outs of the DSP units into the "line ins" of the TNP, then it cannot be done without multiple units.

I hope that is sound logic.
Title: "DIRECT DRIVE" VMPS for DEQX/TACT systems and VMPS
Post by: John Ashman on 30 Apr 2005, 04:57 pm
The only other option, if you have 3 *identical fronts* is to buy two or three Trinaural units - one for each frequency range.  But that hardly saves you any money either.  DEQX has said that a 3-channel processor is in the agenda, but who knows when it could emerge.
Title: "DIRECT DRIVE" VMPS for DEQX/TACT systems and VMPS
Post by: PLMONROE on 30 Apr 2005, 11:14 pm
Yes, I do have three identical fronts (three RM-40s). John, I was thinking the same thing -- I am hoping that doing room equalization just ahead of the trinaural might work since it derives the signal for the center channel amp.  Alternatively I might be able to use readings from the DEQX to manually set the parametric equalizers in my Behringer DEQ9426 for the left and right channels and then use the DEQX for the center or something. Any other ideas, anyone?

Paul