Is this a reasonable "dream build"?

[Docks]

In the next few years I would really like to make a pair of speakers. Perhaps using the Scan Speak components used in the ZRT's.

Heres some specs.
Scan Speak Tweeter (Probably 6600) in its separate movable cabinet.
1 or 2 Scan Speak Revelator mids again in a separate movable cabinet.
Finally a JL Audio sub (13W7)in its own separate cabinet (per channel of course)

I could use my QSC 404 to power the tweeters and mids then obtain a Behringer EP4000 for the subs.
Behringer DCX2496 active crossovers, 1 per channel.
Behringer DEQ2496 for room correction.


Active crossovers would help modify phasing and xover points.
The separate cabinets would allow time cohesion based on different room sizes + sitting positions.
The sub would help pick up where the Scan speak left off to carry into the 20hz area.

Cabinets would have to be REALLY well engineered, I want next to no cabinet resonance.

Is this a realistic build idea here?

 

[annunaki]

In the next few years I would really like to make a pair of speakers. Perhaps using the Scan Speak components used in the ZRT's.

Heres some specs.
Scan Speak Tweeter (Probably 6600) in its separate movable cabinet.
1 or 2 Scan Speak Revelator mids again in a separate movable cabinet.
Finally a JL Audio sub (13W7)in its own separate cabinet (per channel of course)

I could use my QSC 404 to power the tweeters and mids then obtain a Behringer EP4000 for the subs.
Behringer DCX2496 active crossovers, 1 per channel.
Behringer DEQ2496 for room correction.


Active crossovers would help modify phasing and xover points.
The separate cabinets would allow time cohesion based on different room sizes + sitting positions.
The sub would help pick up where the Scan speak left off to carry into the 20hz area.

Cabinets would have to be REALLY well engineered, I want next to no cabinet resonance.

Is this a realistic build idea here?

To answer your question simply, yes, I think so.

The questions I would have would be around how high up you plan to cross over a 13W7? I would not recommend this up much higer than 120hz-150hz or so.

Also unless you are playing at crazy levels, a 10W7 may actually be a better choice for you here because of enclosure size. The 10W7 is equal to most conventional 15" woofers in terms of output, and in many cases, extension as well.

The active crossovers are a great choice for a "reference" grade speaker. Full active is the only choice for a a true reference speaker in my opinion.

The use of the Behringer EQ may not be needed since you can EQ using the DCX to a large degree too. The DCX is a VERY comprehensive audio tool!

 

[Docks]

Yeah,

The Scan-Speak revelator can go pretty low.
http://www.zaphaudio.com/ZRT.html
In this application you can see how low it can go.
Perhaps 80hz would be a reasonable xover.

 

[annunaki]

Yeah,

The Scan-Speak revelator can go pretty low.
http://www.zaphaudio.com/ZRT.html
In this application you can see how low it can go.
Perhaps 80hz would be a reasonable xover.

Well it may be a place to start anyway. That is the great thing about a DCX you can constantly tune until you get it right!

I would start with shallow slopes at first assuming the drivers will have no issues and work you way from there.

What do you have for measuring these so you can know exactly what effect you have on the sound?

 

[Docks]

This is all just planning heh.
But a DEQ2496 and some PC based software would help me make measurements. Any suggestions for fine tuning?

 

[TLS Guy]

Yeah,

The Scan-Speak revelator can go pretty low.
http://www.zaphaudio.com/ZRT.html
In this application you can see how low it can go.
Perhaps 80hz would be a reasonable xover.

You need to have the crossover about an octave above where the mid starts to roll off, so about 200 Hz.

Don't forget about step response loss compensation. To avoid stressing the mid is a good idea to let the woofer handle this, in which case you need a woofer with a response to around 1 kHz.

 

[GranteedEV]

Exodus is coming out with a new 8" woofer soon worth keeping your eyes out for:

http://www.diycable.com/main/default.php

18mm of linear x-max on an 8" driver... put three of those on your speaker and you'll have the cone area of a 13 or 14" driver. Kevin Haskins said it should be able to go up to 2khz smoothly and usable in a low crossed 2-way, but it's probably perfect for a 3-way especially if fs can be sufficiently low.


Anyways I would personally choose different drivers but i think the overall design approach is more important than the raw drivers chosen.

 

[TLS Guy]

Exodus is coming out with a new 8" woofer soon worth keeping your eyes out for:

http://www.diycable.com/main/default.php

18mm of linear x-max on an 8" driver... put three of those on your speaker and you'll have the cone area of a 13 or 14" driver. Kevin Haskins said it should be able to go up to 2khz smoothly and usable in a low crossed 2-way, but it's probably perfect for a 3-way especially if fs can be sufficiently low.

Anyways I would personally choose different drivers but i think the overall design approach is more important than the raw drivers chosen.

Lets wait and see the T/S parameters of that 8" driver. It might make a nice slim line TL.

 

[Docks]

I also got this response:

As a generalization more XO points means poorer soundstage & less coherency. One of the reasons why many are moving to, and living with the limitations of 1-way systems. Of at least talking the lessons learned and pushing XOs in a 2 or 3 way system below 300 hz and above 5k.
How do you guys feel about this? Opinions?

 

[TLS Guy]

I also got this response:

As a generalization more XO points means poorer soundstage & less coherency. One of the reasons why many are moving to, and living with the limitations of 1-way systems. Of at least talking the lessons learned and pushing XOs in a 2 or 3 way system below 300 hz and above 5k.
How do you guys feel about this? Opinions?

There is no doubt crossover points a re a big problem, and in general the less the better and none if possible. I have said that every speaker designer should be a full ranger at heart.

Absolutely if you do, do a three way you want as large a band width in the band pass driver as possible and ideally all crossover points out of the speech discrimination band. The problem is very acute for passive three ways, as very low crossover points present insuperable problems for a reference monitor. That essentially means crossover points 350 to 400 Hz and 4 to 5 kHz. All decent passive three ways I have heard have more or less followed that rule. So active crossovers have huge advantages.

The next problem is that the simpler the crossover the bigger the problems and paradoxically the more complex the design becomes in some aspects.

I find the trick is to really use any drivers acoustic response to your advantage. If practical use the driver's roll off as the entire slope of a crossover section. It sounds simple but in practice things a different, and it takes a lot of patience to configure.

You can get an idea of what I'm talking about here.

 

[annunaki]

I also got this response:

As a generalization more XO points means poorer soundstage & less coherency. One of the reasons why many are moving to, and living with the limitations of 1-way systems. Of at least talking the lessons learned and pushing XOs in a 2 or 3 way system below 300 hz and above 5k.
How do you guys feel about this? Opinions?

As TLS Guy has partially alluded to, much of this is because of passive designs. Active crossovers open things up a fair bit more because of the lack of phasing issues, etc.

Obviously working to find a wide band midrange driver can help out. I know one great potential solution for a wide range driver is one of the Infinity MRS drivers.
MRS driver source

You can view the driver in a speaker here:
http://hometheaterreview.com/infinity-cascade-model-five-loudspeaker/

They are $95.00 a piece but few if any drivers can come close to their on & off axis performance.

WmAx a former member here thoroughly tested this driver and can be used from about 250hz-around 5Khz. They also have unbelievable low power compression and power handling capabilities yet maintain a good efficiency.

 

[Theresa]

yes

I use miniDSPs to crossover and equalize L/C/R/Sub. My center is the 7" Revelator with the Discovery tweeter. It sounds better than the Eton's which are the right and left. All amps are Emotiva with ten channels of amplification. I would not use pro-gear for your L/C/Rs because of distortion and noise but with the subs its probably the best option.