Newform linesource (coaxial ribbons)
LINESOURCE REFERENCE - Ribbon main speaker, rear speaker and surround sound speaker for high end stereo and home theater audio systems.
I am going to try a project using these ribbons which are unlike anything I can find any information on.
It might seem silly that I am asking these questions which are crucial to a decision I have already made , but at this time I am using a pair of the standard Newform R15 ribbons and they are truly wonderful. I have spent a lot of time a/b'ing them to other well thought of tweeters (Morel MDT33-SEAS Prestige 27TBC/G) for two, and the domes aren't close.
1) Has anyone here heard them in the linesource (coaxial) setup?
2) How would you think having the tweeter-ribbon in front of the midrange drivers affect the output. Would there be a "hole" in the response of the mids or would the soundwaves "wrap" around the ribbon?
3) Has anyone seen any measurements of anything similar?
4) Would the high frequencies from the ribbon be exempt from baffle diffraction from the mid cabinets behind them?
When i had a set of Acoustat 1+1 i had thots of adding a pair of R45 on each side.
I've not actually heard them, but i've always liked the concept.
I'd be glad to have you over to hear the R15's or even bring them to your place for some testing/listening. I would be very interested to see some of your projects!
You close by then?
I'd love to hear them.
Newform Linesource Owner
Answers if I can remember the Questions?
1/ I am an owner and I use them for general listening, surround (with Linesource monitors in rear), mixing recordings, mastering recordings.
2/ I can not measure any difference from the woofers, nor hear any difference with the ribbons in front or not. Measurements with SPL meter and RTA with measurement microphone.
3/ I use them at 1k4hz crossover to take the physical limitations of the woofer faces (true to every woofer) out of the equation. 1khz = 12" wave length, 1k4 is about 7", woofer face is about 7" diam.
4/ putting a radius on all corners makes a surface that scatters the wave front based on wavelength/frequency and stops any common nodes. This is done by NFR on the front cabinet corners and on the back of the Oval Ribbons. cut a piece of plastic pipe in half and glue one half onto the back of an R series ribbon to create a radius?
5/ I have ran 1/3 octive, pink noise on my speakers from a 20hz centre to 16khz and measured at the listening position and about 1.5 meters in front of each. I use the extremely flexible Behringer, DCX2496 to control the crossover point, slopes, polarities, time delays (delay ribbon to time align woofer, 5" behind), gains (match woofer to tweeter spl's), and parametric EQ the slow smooth bass roll off as measured in the room.
The tweeter is extremely smooth and the only adjustments made are for the crossover area which is designing to make the woofer to tweeter a smooth natural one that can't be heard.
6/ The Linesource monitors that I use on the rears use NFR passive crossovers which are extremely well done. They roll off in the bass starting around 65hz. They aren't design for a full range speaker. Truth in advertising. This is real world, real measurements. I don't know how most manufacturers come up with the bass responses claimed?? I have never been able to see it, on a plot, in the real world and measured in the real world.
They are excellent for surrounds or a complete system when used with a sub. Every surround preamp allows setting the rears to "small" which sends the lows to the mains and/or sub anyway.
Hope this helps?
Ask me anything and I will try to help.
BTW, I've had many speakers including B&W, Magnepan MG12's, Magnepan Typmani 4A's, PMC..... NFR is the best value for dollar period. R630, R645, Linesource monitors, Linesource Reference....http://www.diyaudio.com/forums/images/smilies/smile.gif
My config is different, as I built them before Newform introduced their coaxial mounting. My ribbons run full-length from floor to ceiling, in an anuminum extruded channel. My mid-bass stacks are actually three Newform cabinets stacked for left channel and three for right channel, with 12 scan-speak total (I sealed the cabinets eliminating the original ports). The aluminum channels have large aluminum plate bases. I usually put the ribbons alongside the mid-bass stack, but I could put them in front. My Rane crossover does provide analog delay if I need it. I don't have the cabinet backs or fronts rounded (very interesting though).
I hope to get two Danley tapped horn subs during the kit sale, depenent on whether I can raise the money by September.
I believe there are some advantages to ribbons that run all the way to the floor and ceiling. Those reflections are problems in most installations, interference causing frequency-dependent comb filtering. But in mine those reflections are merely continuations of the virtual line source now of infinite length. Of course the reflections have less energy so the technique is imperfect.
One thing that's a bit unnerving though is to drive sine waves into your ribbons and listen to how much the timbre changes with drive level. Definitely cleaner a lower levels (what else is new). Also, anything has some resonant band where it is efficient, and though these do cover a wide band of 4+ octaves they are really dropping off well before 16K but so are my old ears. The scan-speak are doing OK well above 1000 so I usually cross higher and wish the ribbons went a bit higher (so I add EQ). The dozen scan-speaks don't make real bass with any slam to it; I was about to add more when I decided to pursue subs. I'd probably get more "psychological bass" with some "slam" but less real extension if I just eliminated the lowest octave (or two, or offloaded the task of handling the lowest 4 or 5 octaves to a real sub). But this is usually not for dance, this is for listening. If I was going to mount the ribbons "co-axially" I'd probably place them in front of or between the mid-bass drivers, with the 6.5 inch mid-bass drivers arranged in two columns, one column of woofers on each of both sides of each ribbon. Might be some concerns with sharing a baffle, might put the ribbon in front with delay. But my point is that when I'm not using subs and I want to play loud and have some real bass, I will require a lot of these small mid-bass drivers, at least 2 dozen and probably more like 40 total; the current dozen doesn't cut it. Then again, my bass driver requirements are a bit extreme due to EQ, dynamic range expanders, and a phase-coupled activator (actually I just sold the audio-control unit and bought a DBX exquivalent I haven't even auditioned yet). I used to use 64 bose drivers for home stereo, so I know enough small drivers can generate some "slam" down to 50, but not down to 20. I'm hoping to side-step the issue with the Danleys, but it would be more elegant to expand the range the scan-speaks handle and have a true 2-way system. If you really want to run the ribbons to a low corssover like 1K, then you can definitely consider larger mid-sub drivers, even much larger ones. Even crossed over higher you could run 8 inch or 10 inch mid-bass drivers in a true two-way system.
I've got a stack of commercial power amps: 5 soundcraftsmen amps (FET outputs, regulated SMPS, 9000 watts total if the impedance was optimized for them, which it definitely is not). I used to have some Crown CE4000 amps also, but had to sell them in tight economic times. I might be helping a friend get something similar together, using Crown K2 amps for the bass and mids with hiis current Adcom for the highs.
Right now my mid-bass sound OK at lower levels. The drivers are not evenly spaced, and I'm pleased any comb-filter effect from this is not disturbing. The scan-speak drivers are still mounted offset in the stacked Newform cabinets. So there's a bit of blank cabinet baffle near the floor, then as you look up there's 2 scan-speak drivers (bottom cabinet is right-side up) then there's two more (second cabinet is upside-down) then there's some blank baffle and two more scan-speak (third cabinet is upside-down). This puts (on each side) 4 dirivers centered vertically on my head/ears in seated listening position and 2 more centered vertically on my head/ears in standing position. Sounds good to me, but I have often considered adding more scan-speak drivers to fill in the gaps. This was not an ideal design, this was something I threw together with a tig welder in an afternoon. The mid-bass cabinets were Newform "blem" vinyl-covered cabinets (looked great to me).
Neither the vertical spacing of my mid-bass drivers nor the side offset between them and the ribbons is theoretically elegant, but is sounds pretty darn good. I've even dragged them outside for a pool party. The long line-source cylindrical wavefront really does propagate well, diminishing only linear over longer distances (instead of square of the distance for a point source).
^^^ A picture is worth a thousand words ............. :)
So here's 2 kilowordsworth:
Final set-up may put the mid-bass in the corner and have curtains and absorptive panels on the wall, and some toe-in. And some subs. Right now they are not operational, as I need to make a fusebox load center that plugs into the obsolete clothes dryer outlet so that I can power the power amps. No point in even trying to run 9000 watts of power amps from one or two 15 or 20 watt wall outlets. Even from the dryer connection it's dubious.
Hi cycle camper.
I suspect the "lack of slam" is from sealing off the ports in a cabinet tuned for the ports??
My cabinets are designed to be sealed to start with, so it isn't a compromise and the infinite baffle keeps them very room independent.
It is very very good to get the effect of a near field monitor with the natural dynamics in a larger room (or outside as you did) using the linesource design. :-)
I highly recommend the deq2496 and it has parametric eq as well so you could try to offset the bass roll off from sealing the tuned port.
I now have my reference and monitor models in my new studio and they perform incredibly.
Mr. Meyer has a killer line with excellent price points.
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