That distortion measurement was with the speaker pulled out into the middle of the room (easy with wheels!!) and UMIK at the tweeter axis - tip 1 m from the front baffle.
That graph has nothing added as REW does it's own thing on the distortion tab - but when doing freq measurements, I usually gate the top end just above first reflection point, use a combination of the freq dependent windowing function at 1M, near field measurements and listening position MMM with RTA and pink noise for the lower end and lower mid.
Hi, I’m loving this build and it’s got me thinking about trying a build myself! I have a couple of ideas you, or others, may have tried and dismissed before…
1) What is the effect, on output/response, of rotating the subs through 90deg, either horizontally or vertically? Regarding horizontally, I assume some sort of boundary effect from the close proximity of on driver to the floor.
2) Have you considered mounting the plannars and midwoofer using an anti vibration membrane in place of the support wire?
I guess I’m thinking CLD type frame but drivers are mounted on the damping material.
Many thanks for sharing!
You mean 800Hz. 800kHz is almost FM radio
Those tweeter measurements are impressive. Can you show the XO curves (measure woofer / tweeter / combined as separate curves)?
Hi X - all 24dB LR symmetrical - to me they have always given the best overall result - but YMMV.
I will share lots of photos tonight if you like with the technical DSP stuff!
Hi CJ!
1. Rotating the subs is a big no no - as they are dipole.....so the front/back has to be pointed towards you - when I stand on the side of them the bass drops off to nothing!! This is a big plus with dipole bass as it effectively removes one complete plane of reflections - ceiling/wall/floor everything in this plane - hope this makes sense!
2. There is just no need for CLD with the wires - but I am not sure CLD would be enough without them? Suspending the drivers from wires/cables effectively completely isolates the mechanical vibrations.
If I was mounting woofers and certainly subwoofers to a baffle like this I would probably make it out of a ridiculous overbuilt CLD construction- like 15mm aluminium/3mm sorbothane/15mmaluminium or something.....with incredible mass and internal damping.....
Hanging them just so effective!
Thanks bushmeister,
Few more questions if i may:
Assume plannar arrangement (mid-high over high) is due to the height they end up at?
Any concerns regarding stress on the sub magnets when holding them in a cradle? I was thinking of additional wires from the top three connecting rods might be prudent?
How do you arrive at the distance between sub driveunits - is it a rule of thumb or trial and error?
Cheers
Few more questions if i may:
Assume plannar arrangement (mid-high over high) is due to the height they end up at?
Any concerns regarding stress on the sub magnets when holding them in a cradle? I was thinking of additional wires from the top three connecting rods might be prudent?
How do you arrive at the distance between sub driveunits - is it a rule of thumb or trial and error?
Cheers
No worries!
Yes - I made a mock up with the tweeter in the usual spot and it was way too high!
But given is isn't too large, and I overlapped the tweeter and mid, didn't worry too much about the 4cm increased distance between mid and woofer!
The subs I have actually have the balance point where they are slung and the magnet is far heavier than the cone/frame, so in my eyes this is a better way of suspending them than the heavy magnets hanging off the frame!
It made me realise how much stress is put through the frame by a 2-3kg magnet hanging off the back!
Distance from sub to sub - as per linkwitz's study I just made it up - 10cm spacers were used!
I wanted enough to clear the massive suspension rolls and 26mm xmax they have, but not so large that it looked a bit silly!
Thank you sir - again you are an open baffle inspiration and had a hand in the creation of this project with your excellent speakers and threads!
Here you go X,
DSP settings at present - much more work to do...
I will do you some quick measurements now though as promised with the acoustic slopes at 1m
DSP settings at present - much more work to do...
I will do you some quick measurements now though as promised with the acoustic slopes at 1m
Attachments
And X, just because I care....here are some quick 1m measurements just done for you.
Please bear in mind this is about 1 hours work on the crossovers and EQ and I will probably change this all up after my weekend of measurements mayhem
Please bear in mind this is about 1 hours work on the crossovers and EQ and I will probably change this all up after my weekend of measurements mayhem
Attachments
Thanks! You didn’t have to do all this on my account. Sorry to trouble you - just hoping you had the graphs already as you were developing the XO earlier.
Looks great. So LR4 filter then and the 8in planar is working from 600Hz up to 3500Hz. Nice range. Almost like a full range driver. That’s where the magic is.
94dB and flat response through that range - you are encroaching on $750 Volt VM752 territory!
Nice job!
Looks great. So LR4 filter then and the 8in planar is working from 600Hz up to 3500Hz. Nice range. Almost like a full range driver. That’s where the magic is.
94dB and flat response through that range - you are encroaching on $750 Volt VM752 territory!
Nice job!
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No bother at all X - it was my pleasure! Least I can do after everything you have done for the DIY community
You are absolutely right about the planar mid it is very special - I am using the 10" planar now though!
It appears to actually be lower distortion than the volt mid dome and sounds amazing!!!
It is one of the best mids I have ever measured.
More to follow.
You are absolutely right about the planar mid it is very special - I am using the 10" planar now though!
It appears to actually be lower distortion than the volt mid dome and sounds amazing!!!
It is one of the best mids I have ever measured.
More to follow.
Very nice. Very nice, indeed!
Are you saying the 10" sounds better than the 8"? From 600 Hz?
I was going to ask if the 8" slims would do the job at that freq. And maybe all the way up, as a 3-way?
Hmm, have to copy these : ). Anything special to look out for? How is the dispersion/power response at the crossover points? Both from midbass to mid and mid to tweeter. Would it be better or worse with the slims?
Are you saying the 10" sounds better than the 8"? From 600 Hz?
I was going to ask if the 8" slims would do the job at that freq. And maybe all the way up, as a 3-way?
Hmm, have to copy these : ). Anything special to look out for? How is the dispersion/power response at the crossover points? Both from midbass to mid and mid to tweeter. Would it be better or worse with the slims?
Thanks Keegan!
So with naked dipoles the whole idea is to keep the dispersion in dipole behaviour from as low to as high as possible. This means you can forget about the usual monopole matching of dispersion/power response and looking at driver beaming/size etc.
The dipole dispersion is all about keeping the rearward wave and front wave as close to each other throughout the passband of the driver so that the dipole cancellation happens consistently - some of the other open baffle gurus will be able to explain this much more elegantly I am sure!!
In fact - this is Charlie's thread about it all that got my cogs turning......Read his white paper attached to his opening post:
In Pursuit of a 20-20k Dipole Loudspeaker
So I will post some decent polars this weekend (it takes time with measurement string, protractors etc to do it properly!) - but hopefully these speakers should have lovely dipole behaviour throughout most of their range....
Regarding the 10" versus the 8"/6" GRS planars, I used the smaller mid down to 800hz and wouldn't' go lower than this - it was also pretty low distortion and sounded great - but not as good as the 10" and didn't measure quite as well....however the 10" mid is 3x the cost.....so take your pick!
I didn't try the slims - but they are supposed to be great right up to 20KHz from about 800-1000Hz up. They would be fine as dipole mid/trebles too - but would have more limited vertical treble dispersion with their height - so this would depend on your chosen application/listening height/distance etc.
Hope this helps - let's also hope my polars aren't too disappointing this weekend
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Just discovered this thread and I have to say I love the industrial art architecture look. I'm sure the sound is as fabulous as you say. Having first heard this sound idea from the Celestion 6000 and Mr. Linkwitz brilliant designs, I think you have made a fantastic contribution. Having the DeltaLite cover the 100 - 600Hz range would have Arnie Nudell smiling and nodding his head, yes yes a bass coupler in the power region.
Thanks so much for your kind words, I think you are more sold on the aesthetics than I am!!
My 'balls of prestige' were to my eyes much nicer, and every time I walk into my man cave I am still caught out by the size and height of these things. Everyone in my family - kids, wife and in fact even friends have moaned about me switching the balls out for these huge monstrosities
But for me, it is all about the sound - why else do we do this, right? And to that everyone agrees - 'Yeah dad I get it, they do sound better, but they are just so......ugly.'
Ahh well. Time will hopefully get us used to them!!
My 'balls of prestige' were to my eyes much nicer, and every time I walk into my man cave I am still caught out by the size and height of these things. Everyone in my family - kids, wife and in fact even friends have moaned about me switching the balls out for these huge monstrosities
But for me, it is all about the sound - why else do we do this, right? And to that everyone agrees - 'Yeah dad I get it, they do sound better, but they are just so......ugly.'
Ahh well. Time will hopefully get us used to them!!