tri-amping and active xover - TOTAL SEPARATES?

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Are you referring to the theory that intermodulation caused by the cone movement causes doppler shift or some similar distortion of the high end?

I used to subscribe to that theory but I haven't been able to convince myself that I can hear it. As long as a driver is operated within it's linear excursion limits I haven't been able to detect any extra distortion caused by wide range operation, such as 40-2,400 Hz. in an MT.
 
Re: Crossover Decision

gni said:

The choice of electronic crossover in the end is one of personal preference. Buy from a place you can return. . .what is good for
one persons ears my sound harsh to anothers. ...

Let me know if I haven't answered your question. Professional
equipment can provide some pleasing results in the home listening
environment...


I am using a BSS 366T Omnidrive Compact Plus

It sounds better to my ear than the unmodified Behringer 2496 that I originally used.

Having said that, the BSS unit has more bands that can be used than the Behringer.

If you're using 48DB slopes or 52DB (the BSS offers 52DB NTM slope) you run out of bandwith on the Behringer and can go a lot further with the BSS.

Some really critical listeners prefer the 52 DB slopes in my system.

Active is the way to go, tough to do 48DB at 95 hz passive.

Removing the bands above 956 hz and below 95 hz really bring life to the Lowthers in the Azurahorns

don't forget, you're also removing the bandwidth from the amps.

Am triamping - tube amps on top two levels still not in, using Crowns for now.

NHT1259 Subs
Azurahorns - Lowther DX4s
DDS ENG 90 -1 pro - I inch Wave guide with 1 inch radian compression driver.

Heard it triamped with tubes on the top two for the first time last weekend.

Had a group of Dixie Bottleheads in that brought a couple of homebrew tube amps with them.

When the tri-ampied tube amps went on-line - everybody got very quiet - listening. Ususally, these guys are yacking so much you can't hear the music.

I would say it's a hit
 
Re: Vandersteen Boxes

Not sure where this is coming from. My understanding is that VAndersteen uses passive xovers at the line level, then active at the amp level.

As for "single driver", this discussion is about "TOTAL SEPARATES", not just a single driver. I agree entirely that a single driver doesn't make any sense in creating a full-range full-spl equalized sound stage. However, putting each driver in its own separate ideally designed box for that drive (usually probably just a vas sized square stuffed properly to prevent any standing waves, with 1 inch thck walls. Some driver boxes may be better ported, others not, but the concept was the single best drive for THAT driver. The placement of the drivers could then be done in whatever fashion you wanted, with damping materials between them if necessary. One of the interesting things is you could place them to account for any room issues and time arrival synching to the primarily listening area. Also, the issue of being able to properly size amps for the appropriate badnwidth needs (tweeters need far less wattage than woofers, for instance), or choose an amp for other reasons that might make for a better match for that particular spectrum.

Anyways, see my above post re "ideal" setup. Also, the VAndersteen boxes are sized differently, it would appear to account for time synching, but that they are actually all in one physical unit (like a Watt puppy or what Meadowlark was so consumed with).

Actually if you look at the way most professional (indoor amphitheaters or outdoor concerts) are set up, THAT's very close to what I'm talking about here. Just DIY using consumer or low-end pro (DXC2496 might fit that category, though I hink Behringer would disagree) equipment in a home environment (which isn't accoustically designed like an ampthitheater).

gni said:
It seems to me that Vandersteen isolates their drivers
and uses mostly passive components to bring things
back into phase and levels. Something that would be
done with the active crossover. It just seemed that
Vandersteen was doing what the original post wanted
to do, but now use active crossovers. . .

I've heard the Vandersteen loudspeakers and they did
sound "unboxy" at points. The ability to isolate
the driver baskets is a plus, but it physically puts
distance between them causing phase problems.

Like all things, fix one problem, create two new ones.

The whole point is to get good sounding audio in "your"
listening environment. I think that fact gets lost on a few
in this forum. Each environment requires a different solution
to good sounding audio.

I think the "single driver" group makes great points.

but

a single driver just can't produce the complex sound
waves in all the octaves that humans hear. Period.

Depending on the source material. . .a good single
driver can perform very well. If I only played jazz LPs,
I could design a great single driver that makes your
neighbor's $50K audio system sound like a cheap
Bose Acoustic Wave Radio (isn't that a single driver
per channel?).

I think that it has been well established (not in a conservative
way--in all practical experience that is) that you need two or
three drivers of some sort to reproduce the sounds that
a human can hear.

Passive components do introduce and create new problems
when introduced into the audio signal path. I would rather
use the components in an active manner (isolated and controlled).
It just provides better control of the signal and allows the use
of lower power amplifiers and a chance to better match an
amplifier type to the transducer type.

Chris
 
Re: Re: Crossover Decision

OMG a 52db slope! I'm getting hard just thinking about it! I definitely have to check this out. Thanks for the info, this is exactly the type of stuff I was hoping to generate! 52db slope! Yeeeeeehaaaaaaa!

Ken L said:


I am using a BSS 366T Omnidrive Compact Plus

It sounds better to my ear than the unmodified Behringer 2496 that I originally used.

Having said that, the BSS unit has more bands that can be used than the Behringer.

If you're using 48DB slopes or 52DB (the BSS offers 52DB NTM slope) you run out of bandwith on the Behringer and can go a lot further with the BSS.

Some really critical listeners prefer the 52 DB slopes in my system.

Active is the way to go, tough to do 48DB at 95 hz passive.

Removing the bands above 956 hz and below 95 hz really bring life to the Lowthers in the Azurahorns

don't forget, you're also removing the bandwidth from the amps.

Am triamping - tube amps on top two levels still not in, using Crowns for now.

NHT1259 Subs
Azurahorns - Lowther DX4s
DDS ENG 90 -1 pro - I inch Wave guide with 1 inch radian compression driver.

Heard it triamped with tubes on the top two for the first time last weekend.

Had a group of Dixie Bottleheads in that brought a couple of homebrew tube amps with them.

When the tri-ampied tube amps went on-line - everybody got very quiet - listening. Ususally, these guys are yacking so much you can't hear the music.

I would say it's a hit
 
Are you referring to the theory that intermodulation caused by the cone movement causes doppler shift or some similar distortion of the high end?

just quoting Lenard Audio, I believe what they say as I have heard their 4 way active systems, The effect is a realism and naturalness that has to be heard to be believed.

As I cannot afford such a system and so much is to do with the amps ect plus the wife and her dislike to large objects in her house!!!! it would be a complex DIY nightmare for me, but definitly a project to try for the less haint hearted. If or when you get it right the results I believe would be worth the effort. The results are exceptional, and only then could you hear the difference.
 
FDS-366T OMNIDRIVE COMPACT plus

Just got done reading up on what is now known as the " FDS-366T OMNIDRIVE COMPACT plus " (new version, but looks like same device) and it does look fantastic. It was unclear to me if it offers the ability to implement L-R xovers or any other types (a la DXC) or if they are saying that the "WHISEWORKS - Neville Thiele Method™ filters " (including the rest of the device's capabilities) get rid of the of need for "traditional" xovers (though they must be implementing SOME type of xover design to bandwidth combine and transfer)?

Also, has someone done a A/B (or similar) comparison between this and the DCX2496? I'd also like to see this thing opened up, what kind of components they're using, etc (like when I saw the in-line mute in the DCX, that was a dissapointment from a design standpoint)?

Thanks for the input!
 
Cameron -

I'm all for large 3-4 way systems, I just think (without being able to prove a thing) that the main benefit is keeping the drivers operating well within their most linear range. I'm guessing that doppler effect is overwhelmed buy excursion related distortions.

Why is it that small people don't seem to understand that large people like/need to have large things around? ;)

TL -

From the installation spec:

Each crossover output band shall be selectable to operate with a slope of 6, 12, 18, 24, 26, 48 or 52dB per octave. The filter types available shall be Butterworth, Bessel, Linkwitz-Riley or NTMTM*. Each band shall have polarity inversion switching and phase adjustment at each crossover point. Each band shall be adjustable for both high and low-frequency roll-off points, individually or in crossover pairs.

The NTM(TM) filter is just a trademark way of saying that it makes it easy to impliment a Cauer/Elliptic filter. This is probably easier to do than on the Behringer, whose notch depths are limited to 15 dB IIRC.
 
FDS-366T OMNIDRIVE COMPACT

A little $$$$$$$. It seems like you could do it for a lot less money.

Nice features though!

Keeping drivers within limits is the single most important
way to reduce distortion caused by the driver.

Ploping all the driver into one box is just a bad idea.
Each driver in an individual box can be positioned
to passively correct for time delay and thus phase
problems. Every home could sound perfect if we
left behind the single box loudspeaker. Thank
JBL, Polk, Circuit City, etc for this. One stop crap
to make the weekend Yuppie feel good.

Chris
 
Re: FDS-366T OMNIDRIVE COMPACT

I felt some sarcasm dripping....

Obviously we aren't talking about a Typical Home Setup, *I* (as the originator of the discussion and thus get to decide what it's about) wanted to figure out if there's a way for me, as a DIY speaker builder, also getting into DIY amp building, could also switch to active xover's and what would be the best way to do that and even if it made sense to do it.

Right now, I think most folks in this discussion agree that active xover is the way to go, I think the open issues are still WHICH (home grown all the way to professional models -- DCX2496 was my first "love" to the BBS model I recently read up on, but that may be changing) and the second issue is whether or not to go TOTALLY SEPARATES (as the original title implies).

Going with Totally Separate enclosures for each driver makes for a lot interesting possibilities for the DIY speaker builder (someone who can drank out a box fairly easily). Obviously most of us aren't here to be concerned about the impacts on the commercial "schlock" market. (Though my Paradigm 100 ref 3's, which I use for my "reference speakers" are commecial and sound FANTASTIC).

And so there it is...


gni said:
A little $$$$$$$. It seems like you could do it for a lot less money.

Nice features though!

Keeping drivers within limits is the single most important
way to reduce distortion caused by the driver.

Ploping all the driver into one box is just a bad idea.
Each driver in an individual box can be positioned
to passively correct for time delay and thus phase
problems. Every home could sound perfect if we
left behind the single box loudspeaker. Thank
JBL, Polk, Circuit City, etc for this. One stop crap
to make the weekend Yuppie feel good.

Chris
 
lenard Post #69
Man, those things (all their models) sure look incredible. I read that "investment" page, but at the end, wasn't sure what the heck was going on? How/where do you buy/demo these things?


Well If your ever thinking of a trip to australia, The Chauvel Cinema in paddington (near CBD) features the 30ft wide sound system. As bis as the screen. They also plan to open a store in surry hills soon.

Lenard Audio has sold systems all around the world, so perhaps an email to him through his site would get a response, he does not bite.


SORRY MY EARLIER POST WAS WRONG< 3 OCTIVES PER SPEAKER>
Just rereading the education page in lenardaudio.com
 
Individual Enclosures

You said it best in the beginning:

Wouldn't the best possible design here be to put each
drive in its own "box" best for that particular drive
(woofer, mid)? Then possibly use one of those "new"
external "mega" standalone tweeters with their own
external connections already built on? (I know I've seen
these in Voice Coil or somewhere).


Start with the full range (200 Hz to 12,000 Hz). It will carry
almost 50% of all the music that you will hear. Depending on
what you think the system is lacking:

[a] sub and electronic crossover

super tweeter and electronic crossover

But focus in on getting the first 50% of the frequencies
sounding right. I don't think you need to go to the extreme
of the Omnidrive to get good sound. In the end, you are
going to be listening to
the system more than anyone else. There are some great single
driver threads. . .they got the right idea, but as you well know,
you still need the low end and the high end. That high end is
about 50% of the music spectrum! No wonder the single driver
people like records (the speaker can't reproduce the pops and
clicks and they can't hear them).

[SuperTweeter] 10,000Hz to 20,000Hz (10,000Hz) 50.1%
(Electronic Crossover around 10kHz)
[FullRange] 300Hz to 10,000Hz ( 9,700Hz) 48.5%
Electronic Crossover around 200Hz to 300Hz)
[Subwoofer] 20Hz to 300Hz ( 280Hz) 1.4%

Since the sub will be asked to reproduce frequencies up to
300 Hz, you will need two (one for each channel). At that
frequency the channels will be getting different information.

Pick up a car crossover and try it (cheap way). You will quickly
get an idea of how it will sound.

I hope this all helps. It seems the thread has gone full circle.

Chris
 
Converting Existing Equipment to Active Crossovers

I have converted most of my equipment over to
electronic crossovers. I left the passive crossovers
in the boxes and added bypass switches. I also
installed three sets of binding posts on the back
of the speakers to allow the individual drivers
to be driven from different amps. I also rewired
each passive crossover so there was no electrical
connection except outside the box.

Therefore:

I can run the sub -->xover-->threeway loudspeaker
(two amps)
or

Woofer -->xover-->Midrange and passive to tweeter
(two amps)

or
Woofer -->xover-->Midrange-->passive xover-->tweeter
(three amps) running midrange as if it were full range
and tweeter has a single cap.

Not ideal, but working on second xover for the triamp system.

I can have picts later next week.

Chris
 
Uhh, well instead of boxes, why not make them horns?

Essentially I have three seperates.

Two horns and a sealed sub.

While I realize this is DIY forum, IMHO I want to be listening to stuff before I die _grin_. No way I have time to build one, or even time to get into modding A DCX 2496.

tlparker said:
Just got done reading up on what is now known as the " FDS-366T OMNIDRIVE COMPACT plus " (new version, but looks like same device) and it does look fantastic. It was unclear to me if it offers the ability to implement L-R xovers or any other types .......
Also, has someone done a A/B (or similar) comparison between this and the DCX2496?

I didn't do a direct A/B but I did live with a DCX2496 and then replaced it with the FDS 366T in the same system with no other changes.

The BSS unit does everything the 2496 does and more. 6DB butterworth slopes uo to 52DB NTM and everything in between.

The BSS unit uses a 96khz chip - has a number of additional settings that can be held.

The way these things work, say a 6DB slope takes 1 band, making the same speaker take 12DB takes two bands, 18 DB takes more and so on.

The 2496 runs out of bands pretty quickly if you're using steep slopes, it doesn't have as much processing ability or memory in the chip or whatever. With the 2496 I was always running out of memory.

I have never run out of memory on the BSS unit.

The BSS unit is widely used commercially in Pro Sound applications and has more flexiblity. Of course it costs roughly ten times what the Behringer does and is difficult to find used or at a discount.

The BSS unit has greater overhead capability than the 2496

IMHO, the BSS unit is worth the extra effort.

The Behringer is not as lifelike and is a little grainy comparatively.

Since your whole system is going thru this unit, you don't want to be putting a lot of time and energy into a triamped unit with seperates and then skimp on the crossover.

I am using a homebrew Transformer Volume Control 6AH4 preamp. The BSS unit can take an AES digital input from a CD player and with volume controls on the amps, you may well could go straight from the CD to BSS digitally and use the gain control on the BSS for variable volume.
 

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Crossover points

Crown amp takes the sealed subs up to 94.4 hz then 52DB cross to

GM70 75th on the Azurahorns with Lowther DX4's the at 964 52DB cross yp

transitioning an amp for Radian 475PB 1" compression drivers up.

A good rule of thumb is to limit horns (other units also?) to a range no more than a decade. IE 96 to 960 or say 200 to 2000

While I should theoretically limit the radian to 10K, I'm not worry about it at this point - I can't hear over that anyhow _grin_

Attached a pic of the filament supply and power supply for the GM70 amp, will attach a pic for the signal chassis if I can figure out how to reduce the size
 

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I'm late to the thread but, I'd like to contribute ten cents to the passive vs active discussion: (I'm assuming traditonal analog circuits, using active digital changes some of the arguments, but not the difficulty). I also appologize if these have been covered, I scanned but didn't read every post.

1. In order to merge two or more drivers you need accurate measurements of both phase and gain with the drivers mounted in the final box, baffle or horn. Typically, drivers are run near their frequency limits at both ends of the spectrum, this means they are rarely close to phase flat.

2. Designing a summing ciruit that is phase correct is neither easier nor harder in passive vs active, in both cases you need to have a good understanding of how reactive components and circuits work.

3. Accurate measuring tools are needed to see how the combination of drivers and crossover are working together in either case. A complex simulator is most helpful, doing without would be most difficult. In other words, just using your ears probably can't do the job even if you are very good at it.

4. Shelving circuits and or traps are not automatically easier in a passive design although large expensive inductors might not be needed..

5. Active designs mostly need op-amps to be simple, this is not automatically bad, it just adds another dimension to the problem of making first class sound reproduction.

6. Passive designs usually require quite large values of capacitance, for good capacitors this means they are not cheap (or small).

So we are left mostly with a cost and size decision. Please remember that an active design will need three sets (for a three way) of extra interconnects. For first class stuff, this cost is not insignificant. Passive crossovers may or may not need extra speaker wires (depending on which end of the cables you mount the passive) active crossovers will always need extra sets of speaker cables.

So the passive offers easier adjustment (only cause the parts are smaller) because of the phase problem you really can't just stick a pot in the circuit. Admittedly driver sensitivity adjstments are easier by tweaking the gain of various amplifiers. The decision is not automatic, both approaches offer advantages and problems.
 
Oh yeah

If you budget considerations, or don't wanna put the bucks in to give it a try - if you don't mind using Win 98 to interface with the unit for settings -

Suggest you set a search on e-bay for Electro Voice Merlin

These did come in mostly 2x4 or 2x6 configurations.

They have an excellent reputation for being one of the best sounding units and for having some of the best written filter algorithims around.

Highest filter order is 4th order L-R if I remember.

Shortly after I bought the BSS, a Merlin came up on my e-bay saved search - he didn't have a manual and it didn't sell. I called EV, talked with a TEC, found they had manuals and arranged the sale from the e-bayer to a friend for $135 . Later on, found that my friend had backed out without mentioning it to me.

I would have paid that to let it sit on a shelf in my shop _grin_

I started a thread on the digital crossovers several years ago that is somewhat relevant - t least if you are considering purchasing

http://www.diyaudio.com/forums/showthread.php?s=&threadid=41152

IMHO, you are on the right track with seperates.

In my further humble opinion, a good digital crossover is at the heart of your solution.
 
BSS minidrive vs. omnidrive

Can you explain or point me towards something that explains the difference between the BSS 366 minidrive vs. omnidrive? I couldn't find a chart of features of anything like that on the BSS site and it just makes some vague mentions of the mini having "fewer features so we can offer it at lower price". I'd like to get a lot more specific. Any insights or url's to info?


Ken L said:
*snip*
I didn't do a direct A/B but I did live with a DCX2496 and then replaced it with the FDS 366T in the same system with no other changes.

The BSS unit does everything the 2496 does and more. 6DB butterworth slopes uo to 52DB NTM and everything in between.

The BSS unit uses a 96khz chip - has a number of additional settings that can be held.
 
electro voice merlin

I went to the EV web site and couldn't find anything relating to "Merlin", even doing a site/product search. Is there some reason they don't even refer to the product on their web site any more? Seemed odd.


Ken L said:
Oh yeah

If you budget considerations, or don't wanna put the bucks in to give it a try - if you don't mind using Win 98 to interface with the unit for settings -

Suggest you set a search on e-bay for Electro Voice Merlin

These did come in mostly 2x4 or 2x6 configurations.

They have an excellent reputation for being one of the best sounding units and for having some of the best written filter algorithims around.

Highest filter order is 4th order L-R if I remember.

Shortly after I bought the BSS, a Merlin came up on my e-bay saved search - he didn't have a manual and it didn't sell. I called EV, talked with a TEC, found they had manuals and arranged the sale from the e-bayer to a friend for $135 . Later on, found that my friend had backed out without mentioning it to me.

I would have paid that to let it sit on a shelf in my shop _grin_

I started a thread on the digital crossovers several years ago that is somewhat relevant - t least if you are considering purchasing

http://www.diyaudio.com/forums/showthread.php?s=&threadid=41152

IMHO, you are on the right track with seperates.

In my further humble opinion, a good digital crossover is at the heart of your solution.
 
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