Heritage Center Channel

[bodcaw boy]

I assumed 360 degrees just to find the first destructive interference point and then calculated back to make sure it was within an acceptable coverage from each speaker...in other words, I just drew lines [] (one line was a given length and the other line was 1/2 wavelength shorter. Because of the fixed distance between drivers this will force a single triangle. I then drew a line back to the center of the speaker and measured its angle.)

what is distance woof to woof?

Though now that I think about it some more, I was finding the angles of the troughs - the effective -6dB point is going to be slightly narrower.

the coverage pattern of a 12 with a 2" voice coil at around 400 will be approximately, 150 degree depending on how much baffle loading is going on...........

To be honest, I'm not entirely confident on how to accurately predict coverage. I've always gone by the rule of thumb to have same information drivers be within 1/4 wavelength of their top frequency and then just not think about it. If anyone knows of any better ways than manually crunching wavelengths and known phases let me know []

I might have to present an alternative approach I've been thinking about which should alleviate both the side of the motorboard issues and the lobing issues....inspired by the guys over at EAW - yes I know, I need to lose the other pinky toe []

actually i like those guys work......pinky back on!!

boy!!

[bodcaw boy]

Here it is .

No need to look any farther .

nice looking plant!![]

boy!!

[DrWho]

I figure about 18" wide for the squaker and 6" on either side to the

center of the woofers comes to 30" center to center. Call it 34" for

good measure - which is one wavelength wide at a 400Hz crossover.

As far as the alternate design, here is the inspiration from EAW:

(click for larger image)

I love their AX series:

http://www.eaw.com/products/AX/CSA_technology.html

http://www.eaw.com/Docs/AX/AX_whtppr_L.pdf

At a 400Hz crossover, the rear wave will be about 120 degrees out of

phase with the sound from the front of the driver. And then the gap

through which it fires will be too narrow to support any standing waves

in the passband of the driver. I'm not too sure if the ports are going

to be too far away from the drivers, but I think it'll be ok. In this

picture the center to center is reduced to 24". This is the width of

the lascala bass bin so I can't imagine directivity being vastly

different and any distortions picked up from the slot loading should

also be similar.

Check out the polar information here:

ftp://ftp.eaw.com/Loudspeaker_Product_Info/Current_Loudspeakers/AX396/AX396_SPECS_revB.pdf

(pretty much 90x90).

If you wanted to go a step further you could even slide the drivers

further back in the cabinet to time-align with the squaker [] Though

I don't know how to ensure proper loading to the port while keeping the

effective rear volume of the enclosure large enough.

I dunno, what do you guys think? Is it worth the extra build complexity?

[meagain]

Ah! A heritage center channel. Is this for you Who? Or for Colter, or...???

I'm very interested in this. We're using a std. Cornwall laid sideways under our TV as a khorn center. Not good. Sideways LaScala was too deep. I still say there's a big need for this (for the peeps that have big heritage) that's not being filled/addressed.

[DrWho]

This if for whoever wants one...I just like designing stuff and I was hoping to pool in the collective force of the forum. I have no intention of building and selling them. J.4Knee has expressed interest for use with his altec horns and I'll be posting that design up here in a bit. I just want to get the driver seperation issues worked out first. The horizontal off-axis is the biggest compromise to this shape of center channel, so the goal is to minimize it as much as possible.

I'm afraid you're a bit out of luck if you're looking for something that is "small". The K400 horn is 24" deep so it's going to be the same depth as the lascala. If you want something shallower then you'll have to go with a different horn - and once you do that you've lost the timbre matching over the most critical bandwidth []

[Deang]

Does a center channel need low end extension? I ask because Selenium makes a 10" mid-bass driver with Fs of 75Hz, Vas of .95, and a 101dB sensitivity rating. That makes for a fairly small and narrow cabinet -- and only puts you 3dB down in sensitivity compared to a Klipschorn or LaScala -- using only one driver. The driver only goes down to 150Hz though, and I don't know how much more extension you could get in a bass reflex box -- you'd have to do your whiz kid thing an tell me!

I never thought much about different horn types effecting timbre. I always figured if the diaphragms were made from the same material you'd be O.K. -- but I guess you're right. Kind of depressing -- since I was thinking how slick it would be just to use a K-700 with a PD-5 and Bob's CTS-125.

http://www.partsexpress.com/pe/pshowdetl.cfm?&PartNumber=264-432&DID=7

[DrWho]

The goal of the low frequency extension is to match the tonal characteristics of the lascala as close as possible. Though after my last slew of measurements at Colter's place and a few other people commenting on measurements I think I might go with an EBS alignment instead...(which would allow for a smaller diameter, same efficiency driver).

It'd be nice if someone from klipsch could comment on the true performance of the lascala...or better yet I'd love to see some achechoic or at least outdoor measurements.

Those Selenium drivers look interesting to say the least. I'll do some poking around, but I gotta run for now.

[meagain]

Or one of Bob's Pyle Horns . . .

http://www.pyleaudio.com/itemdetail.asp?brand=pylepro&cat1=Pro%20Audio&cat2=Horns%20and%20Tweeters&model=PH2380P

The Pyle PH2380P is 17 1/4" wide vs. the K400 at 18 3/8" but,

the PH2380P is 11" deep including the K-55 vs. the K400 w/ K55 at 23 1/2" deep.

This is the horn Bob uses in his Cornscala II's and sounds really close to the K400.

This would give you Heresy-like cabinet depth (13 1/4") x 15 1/2" high (Heresy width) x 42" wide, a perfect riser stand for a flat screen TV. []

If fact, this cabinet would be the same size as two Heresy's laid end-to-end.

That's what I want (badly). If the sound from it truely would match the Scala/Khorn k-400, that shallow depth would be a godsend. Since so many have at least some semblance of gear at their TV/center location - seems to me the goal would be not to exceed the depth of the components too much. I'd think most would have trouble with a 2 foot deep center. Shaving 6" or more off that 24" depth would be a beautiful thing.

[DrWho]

If you're going to go with a different squaker then you should just go with a heresy. It's already a proven design and was built by much better engineers than myself. Heck, it's already voiced to match the rest of the heritage lineup. The new H3's are fantastic.

[DrWho]

Does a center channel need low end extension? I ask because Selenium makes a 10" mid-bass driver with Fs of 75Hz, Vas of .95, and a 101dB sensitivity rating. That makes for a fairly small and narrow cabinet -- and only puts you 3dB down in sensitivity compared to a Klipschorn or LaScala -- using only one driver. The driver only goes down to 150Hz though, and I don't know how much more extension you could get in a bass reflex box -- you'd have to do your whiz kid thing an tell me!

I never thought much about different horn types effecting timbre. I always figured if the diaphragms were made from the same material you'd be O.K. -- but I guess you're right. Kind of depressing -- since I was thinking how slick it would be just to use a K-700 with a PD-5 and Bob's CTS-125.

http://www.partsexpress.com/pe/pshowdetl.cfm?&PartNumber=264-432&DID=7

Seems that driver isn't any good below 100Hz. I poked around for other 10" and 12" drivers but wasn't able to find anything suitable. 8" drivers are certainly out of the equation.

[meagain]

If you're going to go with a different squaker then you should just go with a heresy. It's already a proven design and was built by much better engineers than myself. Heck, it's already voiced to match the rest of the heritage lineup. The new H3's are fantastic.

[] [:S]

[Mike Lindsey]

JUST SAW THIS AND I WANT ONE!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

I too would want one using a Altec 511B/K55 with Bob's tweeter. I think my shelf above my TV can handle a 44" or 45" wide speaker. Depth is not a problem. I am currently using a KLF-C7 center with my La Scala's, and although it is nice, it's not perfect. This is exactly what I am looking for!!! I would provide the Altec 511B/K55 and Bob's tweeter, but know nothing about the 12" drivers you are using.

Here is a pic of my existing center above the TV. It's an old pic, but the center and the TV are the same. I will go home tonight and check my actual dimensions.

Mike

[DrWho]

If you're going to go with a different squaker then you should just go with a heresy. It's already a proven design and was built by much better engineers than myself. Heck, it's already voiced to match the rest of the heritage lineup. The new H3's are fantastic.

[] [:S]

Did that come across harsh? If it did, it wasn't meant to be and I apologize. I need to not write at 4am when I'm barely coherant.

I was just trying to point out that the H3's are fantastic and probably as close as one is going to get to its heritage brothers in terms of timbre with different drivers. I also wasn't trying to look down on alternate designs. It's just that if one is going to deviate from perfect timbre matching, then why not go a route that is already known to be extremely close and then support this wonderful company?

[DrWho]

JUST SAW THIS AND I WANT ONE!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

I too would want one using a Altec 511B/K55 with Bob's tweeter. I think my shelf above my TV can handle a 44" or 45" wide speaker. Depth is not a problem. I am currently using a KLF-C7 center with my La Scala's, and although it is nice, it's not perfect. This is exactly what I am looking for!!! I would provide the Altec 511B/K55 and Bob's tweeter, but know nothing about the 12" drivers you are using.

Here is a pic of my existing center above the TV. It's an old pic, but the center and the TV are the same. I will go home tonight and check my actual dimensions.

Mike

Ok, that makes two crazies for the 511B [6] - I'm waiting on Jim to provide a rough sketch of its dimensions. I've scoured the interent and haven't been able to find one and am having a little bit of trouble with the dimensions he wrote out for me.

Btw, I'd wager that your TV is right around 40" wide - which would make the available shelf space about 40"? It's probably going to be a real tight fit unless the alternative design is implemented. But if we go that route, then the dimensions of the squaker are going to be that much more important - unless the drivers are mounted on the other side (which would also be better for the port). I need to go run a few more numbers...

[Mike Lindsey]

Who, you're probably right about the 40". I am staying at a Hotel the next 2 nights and will not be home until Saturday to check. The TV is a 43"er and I know that is measured diagonally. I am pretty sure the 511B is very close to 24" in width as it is about the same width as the La Scala. I will check that as well.

Mike

[meagain]

My idea was to separate the bass from the horns. Bass section looking sort of like a subwoofer or at least a rectangular box for under TV. Then the horn section like a petite top piece of a split LaScala to place over TV shooting down perhaps just with a face plate and some very minimalistic light casing surround (even some type of material like a stretchy type to create a sock. Then the depth of the midrange horn might be less of an issue cuz one would angle it down to shoot at you. Why can't the sections be split? My issues with center channels with TVs are - it's my opinion that the center of the TV screen should be in line with your eyes and that many place their TVs far too high. Like putting a Plasma over a fireplace. To me that's not enjoyable viewing. I don't have a plasma, but my DLP has only about 6" below the screen - so not much. I would also like the bass section to not exceed the depth of components.

[theplummer]

Meagan, I've tried that very thing already with "good" success. My problem has always been that my Academy center doesn't timbre match well with my Chorus I's. So, Ihave two center outs on my Sunfire Preamp. I wire the Academy normally and my SW10II subwoofer to the second center channel, then I run the center channel to Wide. This works pretty well, except my sub is positioned about 6' to the right of the Academy, against a side wall, and I am able to detect that the mid bass is not eminating from the center channel. Also, My wife refuses to allow me to bring in my "other Sub" (Dr. Who knows what I'm talkin about) into the living room to take over the sub duties.

My only fear about your idea is the mid bass separation from what the squaker has trouble reproducing and that the separated sub needs to fill in. Maybe if they are on the same vertical plane this would be eliminated.

[meagain]

Yea, I'm thinking like a split LaScala - I think Indy used one as a center in a separated state. But would prefer a split CornScala (or split Cornscala II if the horn specs match up nicely).

[j-malotky]

Yea, I'm thinking like a split LaScala - I think Indy used one as a center in a separated state. But would prefer a split CornScala (or split Cornscala II if the horn specs match up nicely).

My split center keeps up with my Khorns. HF / LF cabs are 8 feet apart and sound pretty seamless, but my seating is 18 feet from the front wall. Spliting let me max my screen size. Doc and many other members have heard my center. Meagain, if you ever want to make the trip north to see my HT, just drop me an email.

I do have some pics on the forum. http://forums.klipsch.com/photos/the_klipsch_gallery/tags/j-malokty_2700_s+Heritage+HT/default.aspx

IMO, If you use a K400 in your mains, you should have a K400 in your center.

I think the H3 is an amazing speaker that should be considered for a center when size is an issue.

JM

[Guest " "]

I don't like these 2 drivers.  The  first one only goes to 4000hz, the second, onyl to 3000hz.  Need a wider performing driver like 290-401, which goes to 5000hz if your trying to emulate the Hersey sound.

http://www.partsexpress.com/pe/showdetl.cfm?&Partnumber=290-401

Also don't think the vent type tunnels depicted in the other thread for side ways mounting of a woofer makes for a wide pattern sound field.