Hi, new to the forum and new to DIY for audio . I have been researching speakers for a while now and I am interested in building a 7.1 speaker system using 7 line arrays. I don't think I have the ability or confidence to design my own system so I was thinking of getting a kit with the components and I could build the cabinets.
The reason why I was thinking line array was b/c they seem to be very dyanamic and able to handle great SPL with low distortion. But I was concerned as to how they would react in a small room that is 17' wide by 20' long by 8' high. The room is a dedicated home theater and I have the room designed by a professional for the room acoustics so it will be heavily treated.
The kit I have been looking at has 9 X 5" mids and 8 ribbon tweeters. What kind of bass could I expect from a speaker like this? What would be the around about equivalent in say 10" or 12" drivers for air movement? (I can't find anything that I could calculate this) I am planing on having the speakers crossed at about 80hz if this design can do it, but the main thing I want is none of that mid bass punch lost. I will be putting in 4-8 18" TC sounds LMS ultras for subs which should be good for 120db at the listening postion up to about 120hz. I currently have some LCR's that each have two 12" woofers and an 8" coaxial driver, each speaker has 2000w capabilities which makes a 6000w front stage. I am looking for something to come close to this setup at the moment (I may have to get rid of this system now for reasons that will take a long time to explain) I don't have a budget but would like to keep it below $40K for the speakers, not including the subs and amps for the speakers.
And thoughts or suggestions would be very much appreciated.
The reason why I was thinking line array was b/c they seem to be very dyanamic and able to handle great SPL with low distortion. But I was concerned as to how they would react in a small room that is 17' wide by 20' long by 8' high. The room is a dedicated home theater and I have the room designed by a professional for the room acoustics so it will be heavily treated.
The kit I have been looking at has 9 X 5" mids and 8 ribbon tweeters. What kind of bass could I expect from a speaker like this? What would be the around about equivalent in say 10" or 12" drivers for air movement? (I can't find anything that I could calculate this) I am planing on having the speakers crossed at about 80hz if this design can do it, but the main thing I want is none of that mid bass punch lost. I will be putting in 4-8 18" TC sounds LMS ultras for subs which should be good for 120db at the listening postion up to about 120hz. I currently have some LCR's that each have two 12" woofers and an 8" coaxial driver, each speaker has 2000w capabilities which makes a 6000w front stage. I am looking for something to come close to this setup at the moment (I may have to get rid of this system now for reasons that will take a long time to explain) I don't have a budget but would like to keep it below $40K for the speakers, not including the subs and amps for the speakers.
And thoughts or suggestions would be very much appreciated.
If you have a 5" midwoofer that has a cone surface of 85 cm^2 and 5mm linear excursion, multiply by 9 (per speaker) and then by 7 (# speakers), that's about the same volume displacement as four 12" woofers with 12.5mm linear excursion.
The bass from a speaker like this may be decent but you're better off handing off the bottom two octaves to a subwoofer, as you suggested. There should be no shortage of output above 80 Hz, to beyond what your ears could endure. One tower with nine 5" mids could generate 110 dB at 80 Hz.
You would have to be choosing very high-end parts to get anywhere near your budget.
The bass from a speaker like this may be decent but you're better off handing off the bottom two octaves to a subwoofer, as you suggested. There should be no shortage of output above 80 Hz, to beyond what your ears could endure. One tower with nine 5" mids could generate 110 dB at 80 Hz.
You would have to be choosing very high-end parts to get anywhere near your budget.
If you are looking into line arrays, you should certainly check out the work of Don Keele.
Don Keele's CBT (Constant Beamwidth Transducer) Page It's a curved, shaded line array and it works very, very well. I spent some time with it (and Don) over the past weekend.
Don Keele's CBT (Constant Beamwidth Transducer) Page It's a curved, shaded line array and it works very, very well. I spent some time with it (and Don) over the past weekend.
Dedicated home theatre room. Seven of these? Nowhere near your high budget:
The Murphy Corner-Line-Array Home Page
The Murphy Corner-Line-Array Home Page
thomasjefferson, thanks for that quick calculation.
And thanks for all the information guys. Those links are great, but I don't have the smarts to design and impliment that design myself.
So is the line arrays the best choice to build a HT with. Like I said before I want something with huge dyanamics and not lose any of that mid bass punch. I am worried that I will encounter problems with the surrounds, is the worry founded?
Theoretically speaking if all was equal, am I correct to assume that if 2 speakers have range of 40hz to 20khz with a sensitivity of 95db, it would not matter if that sound was comming from a couple of 12" drivers or an array of 5" drivers, 100hz at 100db with sound the same?
Anyone got any opinions of what speakers to use for HT , when it is 100% movies only.
Good to hear that it should not cost me as much as I was expecting.
And thanks for all the information guys. Those links are great, but I don't have the smarts to design and impliment that design myself.
So is the line arrays the best choice to build a HT with. Like I said before I want something with huge dyanamics and not lose any of that mid bass punch. I am worried that I will encounter problems with the surrounds, is the worry founded?
Theoretically speaking if all was equal, am I correct to assume that if 2 speakers have range of 40hz to 20khz with a sensitivity of 95db, it would not matter if that sound was comming from a couple of 12" drivers or an array of 5" drivers, 100hz at 100db with sound the same?
Anyone got any opinions of what speakers to use for HT , when it is 100% movies only.
Good to hear that it should not cost me as much as I was expecting.
This is most certainly NOT true. The polar response from those would be completely different and the resulting sound would be as well. The "too wide" directivity of a line array is precisely why I do not use them in any of my home theaters.
There is a lot of debate on that point, but for film, I think that its clear that the directivity should be narrow. For two channel there is a stronger case for wide directivity. Film is always mixed and presented with very narrow directivity sources. Just look at any theater, or film mixdown facility. For two channel wide directivity adds spciousness by compromising imaging. But for multi-channel the spaciouness is in the channel mix.
Keele's CBT isn't all that wide. At the ends it's quite narrow, in fact. A strange effect. Unlike anything I've ever heard.
But I agree about more narrow response and film sound, for sure.
Little line arrays for surround could be nice.
Horizontally the CBT directivity must be wide because it is so narrow.
The CBT was developed primarily as a surround speaker (read Toole) and yes, in that application it would be very good (except in small rooms like mine - you would always be in the near field and the near field of an array is not very stable - see my book).
If you look at the data on my web site you will see that the directivity of a dipole is not that narrow - narrower than a baffled piston, to be sure, but not as narrow as a waveguide.
You owe it to yourself to hear the CBT, Earl. It is quite surprising.
In the horizontal plane only the middle is wide, the ends taper off to very narrow. At the end there was no sound at 90 off axis. (That's a subjective "no sound" but the drop off was dramatic). In the middle there was much more wrap around. I demonstrated this to several astonished listeners.
Note that the middle of this array was the floor. Keele was using the floor reflection to double the length of the array.
Also, just as Keele claims, they sound just the same a few inches away as they do a few yards away. He really has achieved what he claims in his papers.
Sorry, but I disagree here, and the data supports me. The "higher frequensies" are where it matters most.
Before we get too far from what the original post requested .....
What was specified was (in no particular order):
1) dynamics
2) high power handling
3) low distortion
4) budget constraints
5) already designed & tested
I will not argue about the above specs and whether they are critical or not, however, it may be the case that a line array topology will not (easily) satsify those constraints.
My suggestion is that the OP may want to consider horn-loaded cabinets (Klipsch, JBL, etc). The budget constraints may require buying used rather than new.
What was specified was (in no particular order):
1) dynamics
2) high power handling
3) low distortion
4) budget constraints
5) already designed & tested
I will not argue about the above specs and whether they are critical or not, however, it may be the case that a line array topology will not (easily) satsify those constraints.
My suggestion is that the OP may want to consider horn-loaded cabinets (Klipsch, JBL, etc). The budget constraints may require buying used rather than new.
If you really want to go truely high-end, how about these? Raal 140-15Ds, Scan-Speak Illuminator mids and a powered Seas sub on the bottom crossed with DEQX. The quoted price (17k/pair!) is not for a kit but for a finished speaker so it's possible that you could get the drivers alone and be within budget for all 7. Those cabinets sure are nice though 
If you really want to go truely high-end, how about these? Raal 140-15Ds, Scan-Speak Illuminator mids and a powered Seas sub on the bottom crossed with DEQX. The quoted price (17k/pair!) is not for a kit but for a finished speaker so it's possible that you could get the drivers alone and be within budget for all 7. Those cabinets sure are nice though
Brian, with all due respect, those speakers you are recommending have a sensitivity of 88dB.
The original poster stated a desire for dynamics and low distortion (amongst other things). It is doubtful that you could acheive that with speakers that have sensitivity that low. Just my opinion etc.
No offense taken. Maybe it doesn't have the highest sensitivity but I liked the driver selection, the design and especially the build quality which is just simply spectacular. As far as distortion goes, I haven't seen measurements of the Scan-Speak mids but they are the top of the line midrange that Scan-Speak produces. The Raal's are one of the best measuring tweeters you can buy. There's very few drivers out there that can beat either of these drivers in terms of sound quality. He's getting seperate subs so no need to discuss that.
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