7 ch equal power speakers for my living room, active digital

[Coby]

My intention is to build 7 equal speakers for my living room, using DCX2496's to do the crossover and eq duties. That frees me up a bit with driver selection. I've posted over at home theater shack but wanted a bit more varied response. Some really good suggestins for drivers popped up there.
My thought is to use a wide range or extended range driver for the mid, paying attention to wide dispersion and the ability to generate some spl while still staying clean. I like fast speakers as well. I'm thinking of a threeway, since it seems like you take a hit on dispersion characteristics with 2ways, and crossing over into my sub (ava 18" in LLT config). The WR125 looks very attractive, crossing over somewhere between 100 and 300 down low, and 3500ish up high to a as yet to be determined (but the XT19 looks interesting) 3/4" dome tweeter. For the woof, I was actually thinking of a 8" TC Sounds driver (the TC-1000). How high does that go before the offaxis goes to pot?

If my thinking is correct, I might be able to get away with one WR125 and still get strong output, if I cut that puppy off at the knees, say around 300ish...life would be good.

Enclosure isn't normal; right now I'm thinkin' aluminum tube around 12" dia and 12-20" long, either ported or sealed, for the woof, and a sealed enclosure for the WR, and use a tweet with it's own chamber.

I posted this project up on home theater shack but this really seems like the place for meaty discussions with merit.

I feel like I'm starting with the mid choice, so once that's nailed down the rest will fall. There is an older Audax mid (I forget the number...pm170mo or something like that) that looked interesting, as well as some Fostek units, but I don't know what their offaxis performance is and I was a bit worried about getting the lower end out of the Fostex with the modest speaker enclosure volume I'll be providing.

This will take a few months to do; first thing is to order me some drivers and listen to them myself. This will be the first fullrange set I've built. I'm looking forward to it.

I'd love any comments ya'll have. I've got some specific requirements that are driven by having a wife, and the placement of the screen in the living room. There's some pics in the thread I posted at home theater shack if anyone is curious. Here's the link:
7 speaker home theater/music setup

I'd also really love the chance to hear a few of the DIY solutions. I'm in Loveland, CO...if you're nearby, and wouldn't mind showing a stranger your home, please pm me. I'm especially interested in some of the bigger Dayton systems.

[joecarrow]

Hi Coby, welcome to HTguide!

It sounds like an ambitious project; hopefully we can be of some help here. Posting the link to your detailed description was helpful. Here are a few of my initial reactions to your criteria.

1- Ok, you have a max speaker height of 12 inches, correct? Any width or depth restriction?

2- Do you mean 110 db at one meter, or at the listening position? Either way, that's quite loud.

3- Adding some passive crossovers may be cheaper for this than running everything through DCX2496's.

4- What you're talking about here seems to be "low linear distortion". With high quality drivers, this will mostly come down to cabinet construction and room acoustics.

5- "No crossovers between 300 and 3000 hz" is an often cited rule of thumb by the single driver crowd. A properly designed crossover in this range won't be a problem. My crossover is around 1.8 khz, and it sounds outstanding. The Linkwitz Orion has a crossover around 1.4 khz, if I recall correctly. A speaker with low linear and nonlinear distortion and flat frequency response gives great vocal inteligibility.

6- I agree with your goal of having wide dispersion across the operating range; but if you re-evaluate your SPL requirement this may be easier.

7- Phase coherency? Well, a properly designed crossover must account for phase. Not really sure what you mean by the phrase, though.

You're really asking a lot here- it's quite a list. I think it will take a little patience to get through it all.

[cjd]

Methinks you're neglecting baffle step considerations altogether at the moment.

300Hz is right in the middle of vocal range. Why that spot vs another bad spot? A good crossover with well matched drivers should be nigh impossible to detect.

Round enclosures: are you going to "flatten" one side, or were you thinking of putting the driver in the end of the round? For the latter, it's one of the worst possible setups for baffle step...

DCX: I'd reconsider using this everywhere. By the time you have all the amps and cables and crossovers you'll be WELL beyond cost of a quality passive setup. Crossover in the big 3-ways I did can be done for around $200 each speaker. It also still requires you have a good measurement setup and know how to use it.

Given a fixed budget, IMO your plans right now would be spending that cash quite poorly.

Given your SPL desires and overall box size desires, I think you would be well served to consider prosound drivers. 6.5" B&C mid, 10" or 12" woofer ~98dB sensitivity, tweeter, should be able to net you ~92dB sensitivity overall.

C

[ThomasW]

Hi,

I'm in Denver, and of course you're welcome to come down for a listen. I don't have any speakers like you're describing but I have some speakers you might be interested in hearing just for reference..:wink:

It's impossible to get 110dB out of the WR125 in any usable passband. The 8" TC driver is a sub not a woofer (the highish Le is your cue to this).

If you place 3 speakers on the 1/2 wall, you'll have minimal stereo separation and might as well not bother with a center.

Will she let you hang mains from the ceiling with placement on the sides of the screen?

[Coby]

Methinks you're neglecting baffle step considerations altogether at the moment.

I am, because with the design of the enclosure, that's independent and easy to modify and test after the speaker is built. It'll be designed such that the baffle is something that can be bolted onto the finished unit, and I've a waterjet table so cutting out baffles is trivial, with very complex shapes. I'm actually envisioning a baffle with a gentle curve (r of 3-5") in one axis, or a flat one with a random star pattern around the drivers. In any case, I'm pushing that out to the end of the project. The flat surfaces above and below the front three speakers will likely affect the acoustics. There's pics of my living room in that thread I posted, on the second page. The remaining 4 units will be mounted on the wall, with the baffle surface likely some 14" from the walls.

I’ll model up what I’m talking about when I get a chance in the next few days; should make it a lot clearer.

300Hz is right in the middle of vocal range. Why that spot vs another bad spot? A good crossover with well matched drivers should be nigh impossible to detect.

It is…I’m hoping I can go much lower while still retaining the ability to generate some clean SPL with that wr125 unit, or whichever mid wins in the end. Picked that number just because most of the mids I was looking at that had good off axis performance up higher had difficulties down low. It is all about tradeoffs, eh?

Round enclosures: are you going to "flatten" one side, or were you thinking of putting the driver in the end of the round? For the latter, it's one of the worst possible setups for baffle step...

Neither…going to intersect another tube of a smaller dimension that matches the driver into the main tube, then mount a baffle at the driver plane. Easy to optimize baffle design that way. There’s a pic of one thought of how to do it, along with pics of my living room in that thread that was posted, on the second page. It’s not how it’ll look in the end though. I’ll do some more modeling and post to clarify.

DCX: I'd reconsider using this everywhere. By the time you have all the amps and cables and crossovers you'll be WELL beyond cost of a quality passive setup. Crossover in the big 3-ways I did can be done for around $200 each speaker. It also still requires you have a good measurement setup and know how to use it.

The 4 dcx’s will definitely be part of the design effort. Not so much just to satisfy goals, but also because I want to play with them. Having a good measurement setup and knowing how to use it isn't a detriment, it’s a bonus. As far as feasibility of cost, using the DCX’s vs using a passive crossover is about half the cost, until you count in the extra amplification required. The DCX's will run about $100 per speaker(only $67 per speaker if 2 ways), the total amplification will be somewhere around $350 per speaker. If it was passive, I'd guess somewhere around $100 per speaker for the amplification. That's an additional $150 per speaker for the benefits of going active (which are many), which is acceptable to me. If I can find a pre/pro that outputs in digital stereo AES, huge bonus, but I haven't seen one yet.
I'd also have to include the cost of developing the crossovers, which means additional time with using multiple crossover parts if the first attempt wasn't what I wanted. That could easily eclipse my additional amplifier budget in a hurry, as I'll definitely be tinkering to get the effects at the seats that I'm looking for.

Given a fixed budget, IMO your plans right now would be spending that cash quite poorly.

Are there any considerations other than the active crossovers that make you say that?

Given your SPL desires and overall box size desires, I think you would be well served to consider prosound drivers. 6.5" B&C mid, 10" or 12" woofer ~98dB sensitivity, tweeter, should be able to net you ~92dB sensitivity overall.
C

Not as concerned with matching the sensitivities of the drivers…I don’t mind having an 85dB sensitive woofer mated with a 92dB tweeter; I won’t need to pad down and lose a bunch of power through heat because of the active crossovers. The idea of that is offensive to me, actually….such a waste. I have looked at that B&C mid; but I didn’t find much in the way of measurements on it showing it’s off axis performance or distortion characteristics…do you know where those could be found? What are they giving up to achieve that sensitivity? Size of necessary enclosure? Distortion?

I’m not posting a sensitivity criteria, just a dB requirement, because driver manufactures can trade off sensitivity for the ability to use smaller enclosures and have high power handling. And I can chose my amplification with respect to the frequency range of the driver..which might mean some good class D amps for the low end, and some lower power clean amps for the high end, and something reasonable for the mids, in a class AB or H.

[cjd]

You lose excursion in lieu of sensitivity usually.

Driver sensitivity IS an issue (along with excursion) because that ultimately dictates max SPL. Baffle step ALSO can not be ignored at this stage, because it hurts your woofer and mid SPL limits by up to -6dB. But you often gain smaller enclosure sizes as well. As long as you're crossing 60-80Hz to a sub I think you can do well with certain 10" prosound offerings.

You're only going to get away with as few DCX units if you go simpler crossovers, which will cost even less passive... I've also not been particularly impressed with the DCX being used in core listening ranges, though without using such myself it's hard to say just what was going on. You would need at least one DCX per speaker to do what I've done on my 3-ways, I think. Maybe not. Don't remember now. But I think so. I seem to recall a DCX per tower in the BESL 3-ways. Really depends.

There are a LOT of tradeoffs in speaker design, it's always about choosing which matter to you.

As to budget, I just think you're going to give up some SQ for flexibility you don't really need.

C

[joecarrow]

Not as concerned with matching the sensitivities of the drivers…I don’t mind having an 85dB sensitive woofer mated with a 92dB tweeter; I won’t need to pad down and lose a bunch of power through heat because of the active crossovers. The idea of that is offensive to me, actually….such a waste. I have looked at that B&C mid; but I didn’t find much in the way of measurements on it showing it’s off axis performance or distortion characteristics…do you know where those could be found? What are they giving up to achieve that sensitivity? Size of necessary enclosure? Distortion?

The problem I see is that for an 85 db driver, you need 25 db of gain to reach your 110 db goal- assuming you meant at 1 meter. That takes about 300 watts before considering thermal compression or anything else- most drivers simply can't handle that. Far easier would be a 93 db driver, which would only need 50 watts for the same SPL. Most hi-fi drivers don't have the sensitivity or power handling that you need to reach the SPL goal. It's not uncommon to find pro drivers with 95 db or better efficiency and an honest 250 watts of power handling.

In general, pro drivers have good nonlinear distortion due to the effort put into their motor design and construction. They're designed to be usable at 120+ db, so it really wouldn't be acceptable to audio professionals if their distortion rose too quickly with drive level.

On the other hand, their cones are generally made of paper and they have inferior linear distortion performance as compared with home hi-fi drivers. Still, if the drivers and crossover points are selected carefully you can have excellent sound at extreme SPL. When you go to the movie theater, this is probably the type of driver you're listening to.

Edit- to better answer your question, I believe they're giving up a bit of cone stiffness so the cones behave less pistonically (increased linear distortion). Further, they're giving up extreme bass extension with their limited Xmax, high Fs, and low Qts.

You should be able to run your midbasses down to 50 hz easily, though, and pick up the rest with a dedicated subwoofer.

[Coby]

Hi,

I'm in Denver, and of course you're welcome to come down for a listen. I don't have any speakers like you're describing but I have some speakers you might be interested in hearing just for reference..:wink:

It's impossible to get 110dB out of the WR125 in any usable passband. The 8" TC driver is a sub not a woofer (the highish Le is your cue to this).

If you place 3 speakers on the 1/2 wall, you'll have minimal stereo separation and might as well not bother with a center.

Will she let you hang mains from the ceiling with placement on the sides of the screen?

You're in Denver? Sweet...I'd love to get together with you sometime. Thanks for the offer...I'll definately take you up on it. What kinda beer do ya like?

Yea, the TC is definately a sub, but I was thinking of using it to cover from 30ish up to 100hz if I could crossover that low with the WR. Seven of those in a room playing some stereo content using PLXII sounds like fun though, especially with the sub for the infrasonics.

Nogo on the spl from the wr, eh? I was worried about that. They're pretty low efficiency and I wasn't sure how much power handling they had. Sounded too good to be true. Could go duals but I'm worried about the effect on dispersion. What about doing 4 of those Aura mids, with a 3/4" dome tweet on top, crossed over pretty low to a woof or subwoof placed on the side (for the lcr's) and having them placed above the woof in a vertical array for the remaining four speaks?
Eh, just looked at those...man those are some low sensitivity units.
How about the Audax PR170MO? Anyone got measurements on that? Looks interesting, as well as some Fostex units.

Mains will be between 8' 'n 9' apart (depending on acoustical center; obviously maximized) in a 15' wide by 25' deep room. Center is definately needed; the main thrust of this is for 7 channel discrete music and movies, and it anchors the soundstage while freeing up your listening position. Going phantom is fine if you want only one person to experience the localization. Content is finally moving towards true surround sound, which was hinted at back 30 years ago with the Quad movement and never fully realized with the past implementations of surround sound methodologies.

Hang 'em on the sides? Yea, she'd be fine with that for the right side but the left would interfere with walking into the house. And, that would put them well above ear level. As is, placement below the screen and above that half wall is optimum for height, which is a good thing.

[Coby]

You lose excursion in lieu of sensitivity usually.

Driver sensitivity IS an issue (along with excursion) because that ultimately dictates max SPL. Baffle step ALSO can not be ignored at this stage, because it hurts your woofer and mid SPL limits by up to -6dB. But you often gain smaller enclosure sizes as well. As long as you're crossing 60-80Hz to a sub I think you can do well with certain 10" prosound offerings.

You're only going to get away with as few DCX units if you go simpler crossovers, which will cost even less passive... I've also not been particularly impressed with the DCX being used in core listening ranges, though without using such myself it's hard to say just what was going on. You would need at least one DCX per speaker to do what I've done on my 3-ways, I think. Maybe not. Don't remember now. But I think so. I seem to recall a DCX per tower in the BESL 3-ways. Really depends.

There are a LOT of tradeoffs in speaker design, it's always about choosing which matter to you.

As to budget, I just think you're going to give up some SQ for flexibility you don't really need.

C

The DCX can do two threeways or three twoways, so that's two speakers per unit. I don't understand how you'd need one per speaker to do what you did on your threeways...am I missing something?
Baffle step can be ignored at this stage because I have flexibility with baffle design further down the line. In other words....the choice of drivers can dictate the baffle design, if that makes sense. It's not being ignored, it's being driven by other design considerations. I've got more flexibility with baffle design here than the traditional box setup, where the baffle is integral to the volume of the box.
Does that make sense? If I put together the system and find that my slope for baffle step loss starts too high in the chain I can put on a different baffle. I can keep testing and swapping them out till I'm happy. I can put entirely different baffles on each of the 7 speakers, if I want. (though the wife might have something to say about that).

What I'm planning is building one of the enclosures and mounting the speakers and setting the crossovers and running it baffleless to begin with, and testing it to get a baseline. I'll have 2 or 3 baffle designs to mount on to test with after that. If none of those seem acceptable, I run back to the shop and waterjet out some more baffle shapes out of OSB and 30 minutes later, I'm back testing. Settle on a design, make 7 of them, build the rest of the system, mount it in their final resting spots and begin the work of individually tailoring each one's equalization to work with the room acoustics and seating positions.

If you don't have to, why would you limit yourself to one particular baffle shape at the beginning of the project and then deal with it in the crossover, when you can modify the physical characteristics to minimize the amount of eq'ing you have to do to the signal? From what I understand, you can get 6dB of swing with baffle step diffraction...that's a lot to eq. If I can iterate baffle designs without having to build a new enclosure from scratch and modify volumes and ports and whatnot, I'm well ahead of the game.

I can't easily emulate the spherical baffle with this setup, but I can emulate a cylindrical baffle, and that'll be one of my first choices.

[cjd]

Actually, the more I look at/read your specific requirements, the more it seems to be in line with what I'll probably upgrade my HT to. I started a thread on that somewhere. I just have to determine if I'm going in-wall or not. But I think I may snag an acoustically transparent screen and go in-wall. I'd looked at the Auras, the WR-125's, and found myself wandering over to the prosound drivers pretty quickly. I'll be going passive...

You can simulate how a baffle will respond directly, which gives you better information than measurements will. Both are useful...

Cylinder, if you mount the driver on the round, is bad. Sphere is good, cylinder is bad. Unless you're mounting along the edge of the cylinder, not the end.

DCX I think is limited by number of available filters. So target transfer function complexity is what ultimately decides how many of the DCX units would be required. If it can do 2 3-ways (that's 8 filters minimum) it should be able to do 4 2-ways...

C

[ThomasW]

I have a reasonable understanding of surround sound having owned a quad system 30 yrs ago. And I have a reasonable understanding of HT design having helped my stepfather design and build his first front projection theater in 1984.....:wink:

Are the L>C>R all going to sit on the 1/2 wall?

Were I doing that room I'd 'fly' the mains from the ceiling aiming the tweeters at the listening posting. That would allow the greatest amount of separation with the mains.

FWIW, it's really beneficial from an output standpoint to have some baffle surface for the drivers to load to, that way they aren't working as hard as they'd be with just the tubular enclosures...

Audax PR170MO was/is an interesting driver. Problem is Audax has been out of business for years. Everything being sold is old stock. It doesn't seem wise to design a 7 channel system using drivers where replacements may not be available in a short time.

[cjd]

B&C has a mid that people seem to like almost as much as that Audax...

[Coby]

Hi Coby, welcome to HTguide!

It sounds like an ambitious project; hopefully we can be of some help here. Posting the link to your detailed description was helpful. Here are a few of my initial reactions to your criteria.

1- Ok, you have a max speaker height of 12 inches, correct? Any width or depth restriction?

Thanks; been lurking for a few years, actually. Lots of good info and discussions.

Width and depth….kinda, sorta? I want to leave that a bit open. I can go down behind the halfwall, or up behind the screen, or sideways (keeping the overall length under 36”). And I can probably go up a little in height….to say 14” or so, by changing screen location. Not optimal though, because of the viewing angle change on the screen. And the height becomes the width when I place them on the wall and one location is only about 12” wide(either side is open). Orientation of the drivers will change for the on wall units, of course.

3- Adding some passive crossovers may be cheaper for this than running everything through DCX2496's.

It would be, sorta, if I got it right in the first pass. But I’d give up a lot of flexibility and ability to tinker. It’s only cheaper if you take into account the amplification…if you just consider the crossovers it’s cheaper to use the DCX’s.
I’ve got a running spreadsheet going of estimated costs…would that be helpful to post?

4- What you're talking about here seems to be "low linear distortion". With high quality drivers, this will mostly come down to cabinet construction and room acoustics.

I agree with that, and the room is a real problem that I’d like help on. Obvious solutions don’t pass the WAF test. And it’s not a fun room to deal with. Lots of volume for what I consider to be a medium sized room. That’s a whole other thread, methinks…when I get to the testing stage I might have some questions or requests for suggestions of things to try ‘n test.

5- "No crossovers between 300 and 3000 hz" is an often cited rule of thumb by the single driver crowd. A properly designed crossover in this range won't be a problem. My crossover is around 1.8 khz, and it sounds outstanding. The Linkwitz Orion has a crossover around 1.4 khz, if I recall correctly. A speaker with low linear and nonlinear distortion and flat frequency response gives great vocal inteligibility.

I’ll buy that, but there’s the dispersion issue as well. If you cross that low you’re asking a lot for the tweet to do, no? I think I need to hear more setups with particular crossovers; I don’t have enough info to know for myself what the priority on crossover point is. I know that the steep crossover (48dB) slopes will aid in reducing that portion of the freq range where two speakers are sharing the load and limiting vertical dispersion, so maybe it’s not an audible problem, but it sounds good on paper to do as much with one driver as you can.

6- I agree with your goal of having wide dispersion across the operating range; but if you re-evaluate your SPL requirement this may be easier.

I’m open to that. The volume of the area they’ll be in is somewhere around 7800sqft. Seating position is about 15ft from the lcr’s, 6ft from the rears, and center seat is 7ft from the side units. Seating position might move forward a bit, shortening the seat to front distance, but won’t move back.
I like dynamics. I’m excited about the dynamic possibilities with the newer standards (Dolby TrueHD and the like) and I’m building a system that can take advantage of that. I love passages that are whisper quiet then rise to levels that slam you in the chest and then fade away abruptly…it’s an emotional experience. (I’m especially jazzed today because last night we saw Face in concert again last night…god I love that group. If you’re in Colorado, DO find a way to attend one of their shows. They’re a vocal rock band….7 vocalists, no instruments, stunning performances. I’m talking to their sound engineer now about doing a 7 channel surround sound recording; I think the band lends itself to that and would be quite dramatic. Their arrangement of the song Home is sublime and works much better than the original, in my humble opinion).
What spl level (1meter measurement) might be a good goal to shoot for? I think the THX requirement is 105db in a 2000sqft room…been a while since I’ve looked that up though.


7- Phase coherency? Well, a properly designed crossover must account for phase. Not really sure what you mean by the phrase, though.

Just trying to get the cleanest signal possible during those crossover points. Avoiding phase shifts, and using the time alignment of the DCX to align the output of the tweet ‘n mid, so when I’m dealing with the room effects, I’m only dealing with room effects. How important? Dunno…need to listen to comparisons to know for myself.

You're really asking a lot here- it's quite a list. I think it will take a little patience to get through it all.

PS…thanks for reading this and responding. It is quite a list, and there’s more. A lot of folks get intimidated by the number of issues and choose not to post, and I understand that. Any number of individual topics could be threads on their own. It’s a big project, but this will be my equipment for the next 10 years or so, I’d imagine, and I like big projects. Time, I’ve got. I won’t be making the bulk of the expenditures until at least August, hence the early start on the project. I’d like to have a finished product by October, and will include a pre/pro in with that as well. Currently, nothing out there thrills me, but if Emotiva puts out their proposed new pre/pro sometime soon that’ll be a likely option. :T

[Coby]

I have a reasonable understanding of surround sound having owned a quad system 30 yrs ago. And I have a reasonable understanding of HT design having helped my stepfather design and build his first front projection theater in 1984.....:wink:

Are the L>C>R all going to sit on the 1/2 wall?

Were I doing that room I'd 'fly' the mains from the ceiling aiming the tweeters at the listening posting. That would allow the greatest amount of separation with the mains.

FWIW, it's really beneficial from an output standpoint to have some baffle surface for the drivers to load to, that way they aren't working as hard as they'd be with just the tubular enclosures...

Audax PR170MO was/is an interesting driver. Problem is Audax has been out of business for years. Everything being sold is old stock. It doesn't seem wise to design a 7 channel system using drivers where replacements may not be available in a short time.

I can't fly them from the ceiling any wider than they are now, due to the doorway on the left.

I hear ya on the baffle. I'm curious as to what baffle effect the screen above and the halfwall below will add. I'm guessing it'll be considerable.

The PR170MO is being remade as the MaxSpeakers PR65Neo. The B&C mid looks interesting as well. So do some Fostek units. Can you get decent spl and quality with the Fosteks without doing one of those huge backloaded horn arrangements?

[joecarrow]

Wow... I'll assume that you meant 7800 cubic feet, not square feet. Assuming 10 foot ceilings, your room is substantially larger than my entire one-bedroom apartment (630 square feet). That really gives some scale to it- I don't see how you can do this without pro drivers. 105 db at the listening position would be around 110 db (or more) at one meter.

[Coby]

Actually, the more I look at/read your specific requirements, the more it seems to be in line with what I'll probably upgrade my HT to. I started a thread on that somewhere. I just have to determine if I'm going in-wall or not. But I think I may snag an acoustically transparent screen and go in-wall. I'd looked at the Auras, the WR-125's, and found myself wandering over to the prosound drivers pretty quickly. I'll be going passive...

You can simulate how a baffle will respond directly, which gives you better information than measurements will. Both are useful...

Cylinder, if you mount the driver on the round, is bad. Sphere is good, cylinder is bad. Unless you're mounting along the edge of the cylinder, not the end.

DCX I think is limited by number of available filters. So target transfer function complexity is what ultimately decides how many of the DCX units would be required. If it can do 2 3-ways (that's 8 filters minimum) it should be able to do 4 2-ways...

C

Can't do 4 2-ways since it only has three inputs and six outputs. It is capable of doing a 5 way system with an additional mono output (subwoofer, perhaps) and still be able to do parametric EQ and dynamic EQ settings so filter capacity can't be much of an issue. I don't know how many parametric EQ's it can process relative to the outputs; I haven't heard of anyone running out but I'm curious. It relates to the processor capability and bandpass filters consume more than high pass or lowpass. I'm excited to spend some time with it; it's a powerful tool. The dynamic EQ features are really interesting...first application that comes to mind is modifing the FR at different db levels to match the sensitivity curve humans experience...i.e., boosting bass 'n treble at lower volume outputs automatically and gradually. I can also store various settings so my wife can listen to it as she likes it, which is different than myself. That appeals to me a great deal, not to mention having different curves for various program material, though I doubt I'll go to the effort of running different curves for specific content practically speaking.

If it indeed is limited by processor power then I'll just pick up a couple more units. They're only $200 each. How cool is that? :lol:

[Coby]

Wow... I'll assume that you meant 7800 cubic feet, not square feet. Assuming 10 foot ceilings, your room is substantially larger than my entire one-bedroom apartment (630 square feet). That really gives some scale to it- I don't see how you can do this without pro drivers. 105 db at the listening position would be around 110 db (or more) at one meter.

Sorry, yea, cubic feet. That number seems really freakin' high doesn't it? At least I thought so when I ran the numbers. But it's a living room of 15x25, open to the dining room/kitchen, which is at least 13 x 20, with an open stairwell to the basement, with cathedral ceilings of about 12 ft or so, and an open hallway with the first leg around 4' wide by 5' deep, and the second 3' wide by 17' deep.
It's a pain acoustically. The hallway and the stairway to the basement really trap bass, and there's a nice nul almost directly in the listening position for the low stuff. I'll characterize it better when I get some equipment in.

Sq footage of the upstairs is the floorplan I just listed, plus three bedrooms and a bathroom, and is around 1500sqft.

[joecarrow]

I really miss living in an area where real estate doesn't cost an arm and a leg! I know an engineer with two kids living in an 800 square foot house out here. It's tiny, but at least they own their own home.

If you have your own water jet cutting table, you're in luck for room treatments- I saw someone out there who did something really stylish with some CNC cutting on wood.

Thomas, do you remember the link to that? I think I might have seen you post it before.. It had dozens of parallel slots on a board lined with some absorber with standoffs several inches from the wall. It looked kind of Scandinavian.

[Coby]

B&C has a mid that people seem to like almost as much as that Audax...

Do you mean the 6PEV13? I really like that. There's some Beyma stuff as well that look like they'd work. I'd love to see some measurements on them though...

[Coby]

I really miss living in an area where real estate doesn't cost an arm and a leg! I know an engineer with two kids living in an 800 square foot house out here. It's tiny, but at least they own their own home.

If you have your own water jet cutting table, you're in luck for room treatments- I saw someone out there who did something really stylish with some CNC cutting on wood.

Thomas, do you remember the link to that? I think I might have seen you post it before.. It had dozens of parallel slots on a board lined with some absorber with standoffs several inches from the wall. It looked kind of Scandinavian.

I love Colorado...I've done a fair bit of traveling, including living in Germany for a few years, and there's noplace I like more. This house is what I'd call lower to middle middle class living here.

You know, I hadn't even thought of that (room treatment-wj table)....got pics? Sounds really interesting. I'm digging that...there's a big bare space on the right wall (oriented from my chair in the middle of the room facing the screen, see the pics in the other thread) that would be a GREAT spot for an artsy lookin' diffuser.

[joecarrow]

Oh, I found the link!

http://htguide.com/forum/showthread.php4?t=21646&highlight=absorber

It's probably not exactly what you'll need, but I think that cosmetically it looks great, and would be an easy sell. I think a CNC router was probably used, but you should still be well equipped to make something like this. As long as you can do 2'x2' panels, it shouldn't be that inconvenient.

[Coby]

Oh, I found the link!

http://htguide.com/forum/showthread.php4?t=21646&highlight=absorber

It's probably not exactly what you'll need, but I think that cosmetically it looks great, and would be an easy sell. I think a CNC router was probably used, but you should still be well equipped to make something like this. As long as you can do 2'x2' panels, it shouldn't be that inconvenient.

That's slick...and I could put in curved lines instead of straight ones. Very cool!

[Coby]

Anyone heard of or used tweets from either Alcone or Caire? There's some that look interesting....but precious little info on them.

[joecarrow]

Do you have a source to buy them? For such a large project, it might be worth your time to just go ahead and buy a pair and measure them yourself.

I can see why you're looking beyond the usual dome tweeters for this project- 110 db is fairly extreme. Take a look at the waveguide project on Zaphaudio.com. That would be a cheap way to get to 110 db with really nice sound quality.

Alternatively, have you looked at any coaxial pro drivers? These would very easily give you the sensitivity you're looking for, and the coaxial format is helpful considering that your baffle size is somewhat limited.

[Coby]

Do you have a source to buy them? For such a large project, it might be worth your time to just go ahead and buy a pair and measure them yourself.

I can see why you're looking beyond the usual dome tweeters for this project- 110 db is fairly extreme. Take a look at the waveguide project on Zaphaudio.com. That would be a cheap way to get to 110 db with really nice sound quality.

Alternatively, have you looked at any coaxial pro drivers? These would very easily give you the sensitivity you're looking for, and the coaxial format is helpful considering that your baffle size is somewhat limited.

I don't have a source...that's one of the things I was looking for. Well, there was some sources overseas for the Caire, and I've friend in europe so that probably wouldn't be terribly difficult.

The Ciare I'm interested(MT320) is a li'l powerhouse, and I'm also looking at the Morel MDT 37, which is utilizing a smallish waveguide with good power handling (93dB and 200w, if I remember correctly). I had fantasies earlier today of using 8 or 10 of the inexpensive little 3/4" Daytons with the super tight c2c spacing, but then realized that that short of a line array wasn't really on target with the goals, nor would it integrate well with a single (or likely even a dual) midrange alongside it.
Ciare's website is www.ciare.com

I'm still thinkin' the PHL 1220 or B&C 6NDL38 right now for midwoofer duties, getting as low as I can, and trading off to a woof or a subwoof. Not much out there on either of those drivers as far as DIY online community that I've found yet.


Coax's scare me....it's an irrational thing, I'm sure, but putting things in the way of other things just don't seem right. What's been the experiences with the sound quality of the pro coax's? Sure would make life easy. Most are doing horns for the HF, right?

Oh, and buying a pair of whatever I'm planning is definately in the works. Unless they're the diamond Accutons. Wonder if my wife would mind me actually USING that rock I bought her for something that'd bring some joy....