Wesayso, thanks for your reply.
I am sure you have read Jim Griffin's paper on line arrays.
He advises power tapering of 1.5 - 2 to control bloom.
Did you consider that? or are you better off without it?
I read somewhere power tapering takes away some of the lines 'magic'.
I guess you haven't driven your speakers to limits, or have you?
WinISD shows excursion limit for TC9 (equalized, of course)in 2.5L encl @ about 8 Watt.
Do have any estimate how much power your equalized set can take before facing excursion limit?
I am sure you have read Jim Griffin's paper on line arrays.
He advises power tapering of 1.5 - 2 to control bloom.
Did you consider that? or are you better off without it?
I read somewhere power tapering takes away some of the lines 'magic'.
I guess you haven't driven your speakers to limits, or have you?
WinISD shows excursion limit for TC9 (equalized, of course)in 2.5L encl @ about 8 Watt.
Do have any estimate how much power your equalized set can take before facing excursion limit?
I did find that last page but haven't tried anything other than the convolution engine native in JRiver.
While most people in this part of the forum buy new drivers to change/improve the sound I'm just changing parameters or change the target curve in DRC and get a new driver sound that way (lol). Homing in to a clear dynamic engulfing sound from two towers that each fit on an A4 size paper. I guess I could say mission accomplished. The mission being maximise sound SPL and quality on the least amount of floor space.
Keep in mind, EQ-ing line arrays with a Behringer or similar equipment is quite different from DRC.
With DRC you determine a window, sliding with frequency (short at higher frequencies) and therefore I'm EQ-ing the direct (gated) response in the high frequencies while at lower frequencies you're EQ-ing the direct plus reflected sound due to the longer window there.
Based on my experiments over the last two months I'm a true believer this actually works quite well.
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Wesayso,
I am just realizing how powerful a technique this is, and how great it is to virtually "audition" speakers, and the sound of someone else's listnening room! You just need the IR .wav file for that speaker in that room!
Barleywater demonstrated it here in these processed sound clips of the clip 3 from the Subjective Blind Comparo thread for drivers B, A, and F. Change the .asc extension to .mp3 to listen...
From post: http://www.diyaudio.com/forums/full-range/270614-subjective-blind-comparison-3in-
5in-full-range-drivers-52.html#post4266439
Driver B (TC9FD):
http://www.diyaudio.com/forums/attachments/full-range/472951d1426942771-subjective-blind-comparison-3in-5in-full-range-drivers-b-clip-3-c21k.asc
From post: http://www.diyaudio.com/forums/full...in-5in-full-range-drivers-54.html#post4267535
Driver A (5MR450NDY):
http://www.diyaudio.com/forums/attachments/full-range/473136d1427025973-subjective-blind-comparison-3in-5in-full-range-drivers-clip-3-c21k.asc
Driver F (CHN-70):
http://www.diyaudio.com/forums/attachments/full-range/473137d1427025973-subjective-blind-comparison-3in-5in-full-range-drivers-f-clip-3-c21k.asc
So these are based on IR's from my trapezoidal baffle Nautaloss rear chamber with XKi bass FAST speaker in my room.
In the case of the simulated convolution generated clips, no speaker non-linearities exist, and he may have gated out room reflections so it will sound better than the real thing. Maybe what it might sound like in well treated listening room.
How cool is that?
I know!
I saw those samples from Barleywater. Actually Gmad and I had hinted at that solution in prior discussion, I can't remember which thread it was in though. Probably the one with the lock. Using it on a driver is fun though. Sure it has limits, but with an overkill of power available like in line arrays it has lots of potential.
Should I ever decide on a different speaker I would use it again. Think of a synergy setup with all separate drivers/driver groups EQ-ed and corrected with FIR filters, correcting the room sound after that, again using FIR and you'll realise the attraction of the Acourate suite. Want to play with ambiophonics? You can do that too...
BACCH uses convolution in it's 3D holographic playback system...
3D3A Lab at Princeton University
I saw those samples from Barleywater. Actually Gmad and I had hinted at that solution in prior discussion, I can't remember which thread it was in though. Probably the one with the lock. Using it on a driver is fun though. Sure it has limits, but with an overkill of power available like in line arrays it has lots of potential.
Should I ever decide on a different speaker I would use it again. Think of a synergy setup with all separate drivers/driver groups EQ-ed and corrected with FIR filters, correcting the room sound after that, again using FIR and you'll realise the attraction of the Acourate suite. Want to play with ambiophonics? You can do that too...
BACCH uses convolution in it's 3D holographic playback system...
3D3A Lab at Princeton University
I have read Jim Griffin's paper. But I've read David Smith's papers too from the time he worked at McIntosh. That gives a different view on power tapering of long arrays. Look up the posts of "speaker dave" on this forum as he posts here under that name and very generously sharing his views on this matter.
I think a 2 way array as proposed by Jim Griffin introduces a different problem. You'd need a crossover again. And that comes with it's own problems in the off axis response so basically you're trading one problem with another. I was after a time coherent solution and an array of full range drivers comes closest to that.
I wish I had heard a 2 way line array to see if bloom is more of a factor there. Some of the 2 way arrays have a shorter tweeter line. One thing I do believe could work quite well is the expanding array like David Smith used. But again, you need crossovers compared to my chosen solution.
For a relative short array I'd agree on power tapering. But with a floor to ceiling array (an array with a length at least 70% of the height of the ceiling would count as one) I wouldn't. Look at the CBT array papers as well. But contrary to what is in those papers imagine the line array with it's floor and ceiling reflection as Don Keele did with the CBT and neglected to do with the line samples he showed. You'll notice in the CBT papers the bundling in the center where the array seems to behave quite well. If you believe Keele on his CBT principle you'd need to use that same theory on the straight line array.
That would increase the performance in the center of that array tremendously. Now if the floor and ceiling reflections are at lower SPL than the originated sound you just created a longer power tapered line array (lol).
If you used power tapering and then consider the tapering you'd get one big mess (i.m.h.o.)
These are my personal views on this matter of course. This was the conclusion I came to prior to building the arrays, now that they are finished I can't say I'd like to revise that theory. For me it confirms the theory I had was solid enough.
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I don't think CBT tech has much advantages in domestic floor to ceiling arrays.
Again CBT has very aggressive power tapering, like -12dB at the ends, if I recall correctly.
The centre drivers would go absolutely crazy on excursion due too much unequal load sharing, I think esp in a full range 1-way array.
I am interested in power tapering from "anti-bloom" point of view only, nothing else.
Again CBT has very aggressive power tapering, like -12dB at the ends, if I recall correctly.
The centre drivers would go absolutely crazy on excursion due too much unequal load sharing, I think esp in a full range 1-way array.
I am interested in power tapering from "anti-bloom" point of view only, nothing else.
I wonder how a similar line array with ported enclosure or passive radiator would be like.
Tuned @ 20Hz, it should give extra 7/8 dB at 20Hz and 2/3 dB upto 50/60Hz.
Port at 20Hz would be really large and can result in unequal loading of the drivers.
But, 3/4 Passive radiators distributed all over should work.
Or is it an absurd idea for some obvious reason that I can't think of?
Tuned @ 20Hz, it should give extra 7/8 dB at 20Hz and 2/3 dB upto 50/60Hz.
Port at 20Hz would be really large and can result in unequal loading of the drivers.
But, 3/4 Passive radiators distributed all over should work.
Or is it an absurd idea for some obvious reason that I can't think of?
I played around with that idea but dropped it because of uncertainties when EQ-ing the drivers like I do now. Sealed you can boost quite safely up to a point of coarse. (it also deviated from the time coherence I was aiming for)
Placed in a corner you can get a lot of extra gain as well.
Another idea I toyed with (before I actually build the speakers) was tapering of the high frequencies alone. A circuit much like a baffle step compensation at lower points in frequency the further away from the center driver you get limiting only the high frequency SPL. But again, after considering the option I moved away from it based on all info I gathered and discussions I had with koldby and Owen (OPC) who actually had arrays at that time. Without such corrections you can sit or stand without a change in sound (the image moves up and down with you).
When first testing the speaker after completion I was amazed how the sound followed me with the speaker laying flat on the floor testing the drivers with a battery confirming the connections. At that time I knew the blooming wasn't going to be the big problem I had read about. You only hear one driver, the one closest to you. Except for very few recordings it hasn't bothered me yet. Actually it didn't bother me on those few recordings, more like a novelty. A "hey, this sounds different" kind of thing.
Any decent recording will sound fine, without bloom. Life like, is a more accurate description.
Looked for a quote from koldby:
Placed in a corner you can get a lot of extra gain as well.
Another idea I toyed with (before I actually build the speakers) was tapering of the high frequencies alone. A circuit much like a baffle step compensation at lower points in frequency the further away from the center driver you get limiting only the high frequency SPL. But again, after considering the option I moved away from it based on all info I gathered and discussions I had with koldby and Owen (OPC) who actually had arrays at that time. Without such corrections you can sit or stand without a change in sound (the image moves up and down with you).
When first testing the speaker after completion I was amazed how the sound followed me with the speaker laying flat on the floor testing the drivers with a battery confirming the connections. At that time I knew the blooming wasn't going to be the big problem I had read about. You only hear one driver, the one closest to you. Except for very few recordings it hasn't bothered me yet. Actually it didn't bother me on those few recordings, more like a novelty. A "hey, this sounds different" kind of thing.
Any decent recording will sound fine, without bloom. Life like, is a more accurate description.
Looked for a quote from koldby:
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I'm aware of the technology (or something similar) insofar as it makes software versions of mic preamps and guitar amps possible. I don't see why it wouldn't also work for modeling (or inverting?) speaker nonlinearities. I wonder (not really) if the next big thing in hifi will be "sampling" our speakers by running sweeps at various volume levels and using software to "invert" the nonlinearities along with freq/time domain distortion. Thinking about a possible hardware/software implementation of that is making me dizzy...
Another way of looking at window length is by thinking about the difference between equalizers with 15 or 31 or 61 bands. A single band boost with the 61 band eq will cause will cause a longer ring than with the 15 band eq and so could only exist inside of a longer "window".
I don't really know anymore either but I mentioned in post #871 of this thread that you could use the convolution technique to let others "hear" your towers rather than record music playing through them.
I remember that post also, but while were on that subject, can I make that song a stereo recording? Using a convolution of the left speaker IR on the left channel of the song and use the same process for the right channel? Would that be enough? Would it be a fair and representative presentation of my array in my room?
Give it a try. You may find that you notice the room more than in real life where your brain does a better job of tuning it out. Also, a touch of crossfeed could be used if listening with headphones for more "realism". It's a fun experiment if nothing else.
A virtual audition
gmad, Thanks! It is fun! just spent some time listening to my room on my headphones. I'll post a clip when I get new measurements because I changed the downward slope that this measurement has with about 2 dB less downward slope and removed the bump I had in the bass. But it did let me enjoy a comparison to 2 youtube videos I liked quite a while ago.
https://www.youtube.com/watch?v=U1tWyOGaylY
and
https://www.youtube.com/watch?v=T09m0IqSV10
2 very different speakers with very different sound
But I got the track to see if I could get near to the big ones in bass.
That goal was for my Car by the way.
Ah, what the heck, I'll just post this one first, I'll notify when I change the song to the latest spec of my arrays.
www.rsr-concepts.com/diyma/linesample.m4a
Right click download and saveas as I'm not sure my server will stream it, it's a full 6 minute aac file @ 350kb/s
Song convolved with left and right IR response as measured at the listening position. I did throw in standard Crossfeed as defined in JRiver.
gmad, Thanks! It is fun! just spent some time listening to my room on my headphones. I'll post a clip when I get new measurements because I changed the downward slope that this measurement has with about 2 dB less downward slope and removed the bump I had in the bass. But it did let me enjoy a comparison to 2 youtube videos I liked quite a while ago.
https://www.youtube.com/watch?v=U1tWyOGaylY
and
https://www.youtube.com/watch?v=T09m0IqSV10
2 very different speakers with very different sound
But I got the track to see if I could get near to the big ones in bass.
That goal was for my Car by the way
.Ah, what the heck, I'll just post this one first, I'll notify when I change the song to the latest spec of my arrays
.www.rsr-concepts.com/diyma/linesample.m4a
Right click download and saveas as I'm not sure my server will stream it, it's a full 6 minute aac file @ 350kb/s
Song convolved with left and right IR response as measured at the listening position. I did throw in standard Crossfeed as defined in JRiver.
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Point verses Line, my subjective perspective...
I figured I would chime in also, as I have been playing with two different systems I have for a while now:
One is a single driver Alpair 12 system in an Avebury Cabinet. I am almost done installing the hard wood mosaics over the baltic birch cabinets and I am hoping my brother will like these for his Home Theatre rig.
The other system is a "Cheap and Cheerful" 15 speaker/cabinet line array system using a 99 cent "NSF" special buyout from Parts Express I bought over seven years ago. The cabinets are hideous, as this was intended as an experiment.
I find myself in a very frustrating predicament with these two systems.
On one hand, I have the Avebury. Heaps of detail, downward dynamic range (I know, I naughty term around here), full and coherent range, and 3D sound stage. What more could one want? Avebury has all the Hi-Fi-ness one could want, but in my subjective option, they sound distant. They lack "Presence" It is like sitting more in the back of the auditorium of a live show. With movies, I find the dialog gets lost, even with a 4.2 set-up. The characters sound like they are inside the TV. 
On the other hand, I have the cheap array. No sub 80 Hz bass, no downward dynamics to speak of, and some nasty resonances in the mid-high areas that EQ can not fix. I still have the coherent sound as these are run full-range. Yet I like the huge, wide sound stage these have. The walls of my room disappear and I find myself at the venue where the music is taking place. For movies, the scale is right on. The width of the sound field reaches way outside the speakers. Surround speakers do better for projecting sounds in the back, but You still find You will not need side speakers. If I had the choice, I would pick a well built line array with quality components ran in stereo over a point source 7.1 system. Thankfully, I will be using the arrays I have now for surround sound when I build better arrays for the front.
So You can see my frustration. Avebury has the Hi-Fi aspects and the cheap arrays has the presence and spacial aspects I desire.
I agree with what offers have expressed about "bloom", it is definitely recording technique. This is only an issue with closed mic recording, which sounds unnatural and dry to begin with. Yet, I believe You will still enjoy the arrays, as most music recorded that way (Pop, Rock and Metal), will sound like you are at a Disco or a Rock concert, where the instruments and vocals sound larger then life anyway. To me, that is not a compromise at all!
I would strongly consider arrays if You have any females in your household. What Allen! Really? Yes, this in not a typo. My daughter prefers the arrays and so does every female listener I have had over. Why? Because the arrays do not bombard You with a small high pressure point of sound, instead, they spread the sound pressure over a large area. I have found that females, especially, are sensitive to this. My daughter enjoys dancing to the arrays and can tolerate louder listening levels with them. Likewise for my Mum. Both were very uncomfortable listening to the Aveburys. Kids and Mums are perfect unbiased listeners. The key is to get your wife past the size thing. If You build the cabinets like wesayso, that will not be a problem!
So if your listening preferences lean towards a "being there" type of performance, go for point source.
If You want the show to "be here" with You, go for the line source.
Even with cheap drivers, the overall dynamic range of line source is amazing as well as the volume capacities.
Detail, downward dynamics, and smooth highs are going to be traits of the drivers You choose.
The drivers I am looking into are the Fostex FF83wk and the Celestion AN3510. I would consider the Alpair 7, but the bezels would have to be cut down.
I am going to have a driver blow out between these drivers and I may even include the Vifa. But, if I am going to go through the trouble of building a baltic birch cabinet with solid wood mosaics, then I am going to go with the drivers I like the best, even if that difference is small. I will post my results on a separate thread when the time comes.
Having said that, I have not seen anyone upgrade from their Vifa arrays either. So I do not think You can go wrong with the Vifa either.
Allen
I figured I would chime in also, as I have been playing with two different systems I have for a while now:
One is a single driver Alpair 12 system in an Avebury Cabinet. I am almost done installing the hard wood mosaics over the baltic birch cabinets and I am hoping my brother will like these for his Home Theatre rig.
The other system is a "Cheap and Cheerful" 15 speaker/cabinet line array system using a 99 cent "NSF" special buyout from Parts Express I bought over seven years ago. The cabinets are hideous, as this was intended as an experiment.
I find myself in a very frustrating predicament with these two systems.
On one hand, I have the Avebury. Heaps of detail, downward dynamic range (I know, I naughty term around here
), full and coherent range, and 3D sound stage. What more could one want? Avebury has all the Hi-Fi-ness one could want, but in my subjective option, they sound distant. They lack "Presence" It is like sitting more in the back of the auditorium of a live show. With movies, I find the dialog gets lost, even with a 4.2 set-up. The characters sound like they are inside the TV. On the other hand, I have the cheap array. No sub 80 Hz bass, no downward dynamics to speak of, and some nasty resonances in the mid-high areas that EQ can not fix. I still have the coherent sound as these are run full-range. Yet I like the huge, wide sound stage these have. The walls of my room disappear and I find myself at the venue where the music is taking place. For movies, the scale is right on. The width of the sound field reaches way outside the speakers. Surround speakers do better for projecting sounds in the back, but You still find You will not need side speakers. If I had the choice, I would pick a well built line array with quality components ran in stereo over a point source 7.1 system. Thankfully, I will be using the arrays I have now for surround sound when I build better arrays for the front.
So You can see my frustration. Avebury has the Hi-Fi aspects and the cheap arrays has the presence and spacial aspects I desire.
I agree with what offers have expressed about "bloom", it is definitely recording technique. This is only an issue with closed mic recording, which sounds unnatural and dry to begin with. Yet, I believe You will still enjoy the arrays, as most music recorded that way (Pop, Rock and Metal), will sound like you are at a Disco or a Rock concert, where the instruments and vocals sound larger then life anyway. To me, that is not a compromise at all!
I would strongly consider arrays if You have any females in your household. What Allen! Really? Yes, this in not a typo. My daughter prefers the arrays and so does every female listener I have had over. Why? Because the arrays do not bombard You with a small high pressure point of sound, instead, they spread the sound pressure over a large area. I have found that females, especially, are sensitive to this. My daughter enjoys dancing to the arrays and can tolerate louder listening levels with them. Likewise for my Mum. Both were very uncomfortable listening to the Aveburys. Kids and Mums are perfect unbiased listeners. The key is to get your wife past the size thing. If You build the cabinets like wesayso, that will not be a problem!
So if your listening preferences lean towards a "being there" type of performance, go for point source.
If You want the show to "be here" with You, go for the line source.
Even with cheap drivers, the overall dynamic range of line source is amazing as well as the volume capacities.
Detail, downward dynamics, and smooth highs are going to be traits of the drivers You choose.
Nice to know bloom isn't a real issue
The most confusing part should be the choice of drivers in case I dive in at building lines.
I guess the Fountek FR89 should be really good. TC9 can be taken for granted for arrays by now!
The drivers I am looking into are the Fostex FF83wk and the Celestion AN3510. I would consider the Alpair 7, but the bezels would have to be cut down.
I am going to have a driver blow out between these drivers and I may even include the Vifa. But, if I am going to go through the trouble of building a baltic birch cabinet with solid wood mosaics, then I am going to go with the drivers I like the best, even if that difference is small. I will post my results on a separate thread when the time comes.
Having said that, I have not seen anyone upgrade from their Vifa arrays either. So I do not think You can go wrong with the Vifa either.
Allen
Future press release: "Two Towers goes public!"...
Go for it wesayso! I have recently changed into a new career myself. The job market is tough, even with education, experience, health and work ethic on my side. I would have liked to pursue my care giving business full-time, but due to the new laws "forcing" us in the the United States to buy health insurance, I could not keep my rates reasonable for my clients. Luckly, I recently secured a regular position at our local hospital that is year round, full-time, long term and has advancement possibilities. It is tough starting over a a new career, but it is going well though.
I can continue to run my care giving business part-time on the side to fund these audio projects.
As for your idea, I really think You have something here. I think You can keep the Vifa TC9 in production, as You are using 50 for each pair of speakers! Maybe You can offer a couple of different cabinet designs to choose from, the "Two Towers" being your flagship. Maybe You could source a simpler design out, giving people in your area some work, and then You would collect a small royalty. How big do You see this? I see it pretty big. Most consumers can not consider arrays, as they cost so much. But I think the Vifa can full the gap, it is by far the best candidate in this price range. You and several others have proven its worth. Go for it!
I will be praying that an opportunity to use your many gifts becomes available for You...
Allen
...it's special circumstances that gave me enough time to do this project... after a working career of 24 years I found myself without a job. So basically next to no money to spend but more free time.
Lucky for me I had purchased most of the materials needed.
I still haven't got a new regular job, nobody seems to want to hire you if your health isn't up to par.
I'm thinking of building a few to aid in a new career combining it with the work I used to do (ICT and Engineering) but as my own boss. It will be hard enough and not what I had in mind.
Maybe I'll have to build more simple versions of this though, as building a set like I have now takes me a full year.
Go for it wesayso! I have recently changed into a new career myself. The job market is tough, even with education, experience, health and work ethic on my side. I would have liked to pursue my care giving business full-time, but due to the new laws "forcing" us in the the United States to buy health insurance, I could not keep my rates reasonable for my clients. Luckly, I recently secured a regular position at our local hospital that is year round, full-time, long term and has advancement possibilities. It is tough starting over a a new career, but it is going well though.
I can continue to run my care giving business part-time on the side to fund these audio projects.
As for your idea, I really think You have something here. I think You can keep the Vifa TC9 in production, as You are using 50 for each pair of speakers! Maybe You can offer a couple of different cabinet designs to choose from, the "Two Towers" being your flagship. Maybe You could source a simpler design out, giving people in your area some work, and then You would collect a small royalty. How big do You see this? I see it pretty big. Most consumers can not consider arrays, as they cost so much. But I think the Vifa can full the gap, it is by far the best candidate in this price range. You and several others have proven its worth. Go for it!
I will be praying that an opportunity to use your many gifts becomes available for You...
Allen
Thank you for the idea. Not at all representative of the music I usually play though
. But I immediately thought of the Kendrick recordings as I know I spend quite some time browsing their catalog.Go for it wesayso! I have recently changed into a new career myself. The job market is tough, even with education, experience, health and work ethic on my side. I would have liked to pursue my care giving business full-time, but due to the new laws "forcing" us in the the United States to buy health insurance, I could not keep my rates reasonable for my clients. Luckly, I recently secured a regular position at our local hospital that is year round, full-time, long term and has advancement possibilities. It is tough starting over a a new career, but it is going well though.
I can continue to run my care giving business part-time on the side to fund these audio projects.
As for your idea, I really think You have something here. I think You can keep the Vifa TC9 in production, as You are using 50 for each pair of speakers! Maybe You can offer a couple of different cabinet designs to choose from, the "Two Towers" being your flagship. Maybe You could source a simpler design out, giving people in your area some work, and then You would collect a small royalty. How big do You see this? I see it pretty big. Most consumers can not consider arrays, as they cost so much. But I think the Vifa can full the gap, it is by far the best candidate in this price range. You and several others have proven its worth. Go for it!
I will be praying that an opportunity to use your many gifts becomes available for You...
Allen
Thank you for that Allen,
I hope I'm able to do this, even if only as a part to make ends meet. I love music and love to create and build things like this, what's not to like about a combination like that.
My niece dropped by and I forced her into listening to my speakers. She had the same "You are there" experience I feel when listening to the arrays. "like you're in the middle of it and it's happening right there" she said while pointing at the positions of the guitars after listening to "Hanuman" from "Rodrigo y Gabriella".
What processing do you use on the NSB arrays?
My one example of an NSB driver provided by Godzilla for the Subjective Blind Comparo thread is surprisingly good sounding. I can imagine a line array would be quite impressive. They are not as flat in response as the Vifa but nothing a little mild EQ can't take care of to remove that resonance peak.
Your virtual audition of the towers sounds fantastic. Very nice sound - probably close to perfect representation of the recording.
Your virtual audition of the towers sounds fantastic. Very nice sound - probably close to perfect representation of the recording.
If Kendricks could try to control the room just a little... those are grandiose (as always) but the reflections in the room kill the experience! If only they would add some bass traps and carpet, that would help.
I'm sure you are having loads of fun playing around and making your arrays shine!
I kinda miss mine, and I might be itching to start a new project... oh no!