Concrete line arrays

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I agree many years ago I got roped in to help move a set of those Montana monsters and you only do it Once ! How do the Newform ribbons sound? Do you think they are superior to normal quality tweeters?

I do not have a lot of listening time with really high end speakers (and hence high end tweeter arrangement). I’ve owned klipsch horns, cornwalls and top of the line Paradigm.

I bought a pair of Newform Research R645 15 years ago on a whim and have never looked back. IMHO, there is no sound like the NR ribbons. The whole line array arrangement gives such better projection of the sound. The sound from these units is not distinguishable from a point, it’s all around you with layers of depth. Unfortunately the better your gear gets the more frustrated you get with the quality of the majority of recordings.
 
I do not have a lot of listening time with really high end speakers (and hence high end tweeter arrangement). I’ve owned klipsch horns, cornwalls and top of the line Paradigm.

I bought a pair of Newform Research R645 15 years ago on a whim and have never looked back. IMHO, there is no sound like the NR ribbons. The whole line array arrangement gives such better projection of the sound. The sound from these units is not distinguishable from a point, it’s all around you with layers of depth. Unfortunately the better your gear gets the more frustrated you get with the quality of the majority of recordings.

Thanks I knew that to get the best out of something like these you would need to get the full length line source ribbon and not the smaller ones due to dispersion . If you ever get the chance to try a DEQX unit in you're setup you might be surprised and I am not saying pull your passive crossover apart and use just the DEQX .incorporating it and measuring the speakers with it you will get a locked in sound timing and phase perfect ! The soundstage just opens up and speakers disappear and if the recording is crap then at the touch of a button you fix it ,bass too thin,treble unbearable etc . You can have presets stored anyway something to think about for the future . your system would sound astonishing now! Concrete is just the perfect material and what you have achieved will last a lifetime
 
Time alignment

Tell us more about the build? Good idea putting the tweets in front of the woofs. Did you have to do time alignment?

DJN; thinking about your question on time alignment. You are referring to the 0.5’ difference of the 8” voice coil from the ribbon surface correct? My calculations for 11.5’ versus 11’ from my ear is a time difference of 0.0004 seconds (speed of sound 1125ft/s). Is that significant? I don’t know of electronics that can correct that small of a difference (without creating other problems). I must be seriously misunderstanding what you are asking....

Thx
 
My calculations for 11.5’ versus 11’ from my ear is a time difference of 0.0004 seconds
I get 37 microseconds, roughly the same as your quick estimate.

In practice the woofer will be physically slower than the tweeter - it will take longer for the heavier moving parts to respond to an electrical signal - so there will be additional delay caused by this. It's not geometric (path length difference), it's mechanical.

Twenty years ago, I used a string of all-pass filters (each made with one op-amp, All-pass filter - Wikipedia ) to time-align tweeter and woofer in a speaker system. I got a few microseconds of time delay per all-pass filter.


-Gnobuddy
 
I get 37 microseconds, roughly the same as your quick estimate.

In practice the woofer will be physically slower than the tweeter - it will take longer for the heavier moving parts to respond to an electrical signal - so there will be additional delay caused by this. It's not geometric (path length difference), it's mechanical.

Twenty years ago, I used a string of all-pass filters (each made with one op-amp, All-pass filter - Wikipedia ) to time-align tweeter and woofer in a speaker system. I got a few microseconds of time delay per all-pass filter.


-Gnobuddy
Ok, what your saying makes sense....to compensate for the “system” effects and not just difference in distance. Is 37 microseconds relative?

How do speaker manufacturers correct for “system” timing issues like you suggest?

Thx
 
frugal-phile™
Joined 2001
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.. Is 37 microseconds relative...

Kunchnar showed that humans were good to 5µSec (IIRC) was the time difference detectable by humans.

What DJN is referring to, if i understand correctly, is the point in space where the LF driver seems to be in space vrs where the HF is. This value changes with frequency for both drivers.

If you can get that distance down to a 1/4 wavelength then any issues will usually go away — but with an array you still have the height factor where the driver(s) at the ends of the array are further away from your head than the ones in the middle.

dave
 
How do speaker manufacturers correct for “system” timing issues like you suggest?
It's been twenty years, and I may have forgotten some details. But, IIRC, once we'd got as as far as woofer and tweeter mounted in the final-design enclosure, we used one of the pulsed speaker measurement systems (MLSSA, maybe) to measure the time difference between the woofer and tweeter acoustic signals.

(The principle is that if you send one short sharp blip - say a gated tone-burst right at the crossover frequency - into the speaker system, the microphone will pick up two distinct signals, one arriving a few tens of microseconds before the other one.)

After that it was a matter of choosing an appropriate RC value for the all-pass filters, then looking up the time-delay formula for them, figuring out how many of them to string in series to compensate for the woofer/tweeter delay we'd measured, building the filters, then re-measuring to see if the delay had disappeared, or was small enough not to matter.

This was for a two-way active system with one woofer and one tweeter. At the time, I think it was pretty unusual for an affordable active speaker system to include this sort of electronic time delay compensation. Honestly, the last little bit of time alignment didn't make much of an audible difference to me, but some listeners claimed it made the stereo image more "solid", better localized.

Line arrays are another kettle of (stinky) fish entirely. I don't like anything about speaker line arrays, so I'll follow age-old wisdom and say nothing. :)


-Gnobuddy
 
It's been twenty years, and I may have forgotten some details. But, IIRC, once we'd got as as far as woofer and tweeter mounted in the final-design enclosure, we used one of the pulsed speaker measurement systems (MLSSA, maybe) to measure the time difference between the woofer and tweeter acoustic signals.

(The principle is that if you send one short sharp blip - say a gated tone-burst right at the crossover frequency - into the speaker system, the microphone will pick up two distinct signals, one arriving a few tens of microseconds before the other one.)

After that it was a matter of choosing an appropriate RC value for the all-pass filters, then looking up the time-delay formula for them, figuring out how many of them to string in series to compensate for the woofer/tweeter delay we'd measured, building the filters, then re-measuring to see if the delay had disappeared, or was small enough not to matter.

This was for a two-way active system with one woofer and one tweeter. At the time, I think it was pretty unusual for an affordable active speaker system to include this sort of electronic time delay compensation. Honestly, the last little bit of time alignment didn't make much of an audible difference to me, but some listeners claimed it made the stereo image more "solid", better localized.

Line arrays are another kettle of (stinky) fish entirely. I don't like anything about speaker line arrays, so I'll follow age-old wisdom and say nothing. :)


-Gnobuddy

OK, thx for taking the trouble to try and educate me. I will research this more, try and better educate myself and then possibly run some tests. Its a terrible "Affliction" this audiophile hobby.....when is good enough good enough? Seems never.....it is a pursuit or pilgrimage of some sort

Thx Afflicted
 
I am most definitely envious of the ribbons, and i like the placement. They look like they would suit a corner loaded line array (your placement is almost corner loaded as is)

Others are right, some phase alignment, either through XO design (deliberate or accidental, passive, analog, or DSP) may work wonders. Assuming they need any tweaking.

it would take detailed information, to assess that, and if they already give you pleasure; the will to tinker may not be great enough.

Some times, it's nice just to sit back and enjoy the music - rather than begin an incessant quest for perfection


I'm listening to Fountek FW100B8 and Fountek Neo CD 3.5H, in a 3.5 Litre closed box, heavily stuffed, with the ribbon perched on top.
Overly simple 1st order crossover. F3 a guess estimated 100Hz.
A little bass light compared with what I am used to, but tremendously atmospheric, enveloping and spacious sounding.
Other than the awful appearance, I have almost zero motivation to optimise them further.

With a touch of bass boost, I can crank them and rock out with the kids Trap/Dubstep.

I am enjoying the music, any music, enormously - and I believe that i would enjoy your speakers just as they are, and just as much!

Kudos indeed!

I now need to find those ribbons, and buy some!

Although I'll need to sell an organ first!
 
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Its a terrible "Affliction" this audiophile hobby.....when is good enough good enough? Seems never...
I think you just wrote something really insightful, and really important.

I was brought up by a perfectionistic family, learned to be a perfectionist myself, and grew up in a society that values perfectionism. Then I found out a few years ago, to my shock, that mental health professionals classify some types of perfectionism as a mental health disorder - an unhealthy, depressive disorder. :eek:

Oversimplifying it, if nothing is ever good enough, well, you're never going to be happy, right? And if you're never happy, you're depressed, no?

Perfectionism is also closely linked to another mental health disorder, OCD (obsessive compulsive disorder.) We may pity the OCD sufferer endlessly trying to perfectly position all the forks in his silverware drawer, all exactly parallel, all exactly the same distance from each other. But is this any different than the audiophile endlessly trying to design / build / buy / set up the perfect loudspeaker?

For myself, when I found out I had a good streak of the unhealthy type of perfectionism, I made it a goal to learn to let go of the unhealthy forms of my own perfectionism, as much as I possibly could. Like all such journeys, it is a work in progress, and will be till the day I die.

Here is a very interesting article about perfectionism, OCD, and their connection: Obsessive Compulsive Disorder (OCD) and Perfectionism


-Gnobuddy
 
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