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In Reply to: RE: HK/Limage posted by slapshot on June 20, 2014 at 16:30:21
Using the mid/tweeter panel of the T-IV split off from the bass panel I tried the various positions and found that the tweeter does best a bit farther than 3' from the sidewalls when they are very reflective, and can be as close as 2'4" to well loaded bookcases. Any closer, however, and you start having oddly exaggerated inflation of the images to the point of taking them apart. The best example is what I got for a drum kit when the tweeter was about 1.5' from the bookcases on the sidewalls. the various percussion drums cymbals etc. got pulled out from each other to well beyond a person's two arm spans. Not unpleasant but not real either.
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Hi guys. So I will be making a room for possibly 20.7s and I have a choice of 16 ft wide or 18. Given the close proximity the panel has to the side walls if this setup were to be used - would you recommend the wider room? Length of the room can be 25-30 ft.
Thanks Tim
In my experience, if you follow Limage's method, then your speaker will be as close to 6"-12" from the side walls, so even a 16' wide room will be enough for the 20.X
Here is a photo of my room, which is only 15' wide
Photo taken by Thomas Schick, designer of the Schick tonearm
So you are triamping the Full Range?
How do you keep all those tubes cool, especially in HK?
Hi Satie, I am still using biamp, but getting everything ready to go triamp!
Heat is a real problem with all those tubes, the electric bill for air-conditioning is high :-(
1st avoid 2:1 and 1.5:1 length to width ratios. the golden ratio is good.
18 ft is about as good as 16 ft width, neither would be too far or too near. The wider room would be somewhat more flexible, mine is 17' and would be good for an MG20.x with the Tympani I wish I had the extra foot of width.
Tim, I think Satie is more knowledgable about this than am I. I have 3.6s in a room that is 15' by 21', and I think it works well, but it would better if the room were larger still.
I think the larger the room, the better. 20.7 speakers, I imagine, will benefit from a larger room.
Thanks. I am usually posting with my phone and seem to consistently post under the incorrect line in the thread!! :)
Although I am now struggling with a new pair of 3.7i's, until earlier this week I had my IIIa's with the tweets inside about 36 inches from the side walls. Anything beyond a few inches of toe in and the "floating image thing" behind the speakers disappears. I do not know why, though I assumed it was because rear wave loudness dominates front wave with less toe in??
In my room with the old speakers, I used a pair of DWMs to supplement upper bass which got thin when the main panels were eight to ten feet out from the front wall (in my room, the further out from the front wall the less upper bass I get and the more really deep bass I get. At three sevenths of the way out I was flat at 30 hz, but needed reinforcement in the 80 to 200 range, which DWMs fill perfectly). Anyone else needing upper bass reinforcement and wanting a set up WAY out from the front wall, should consider DWMs. They are not subs, they are mid/upper bass reinforcers. They allow perfect bass smoothing and reinforcement.
Right now I am still trying to get the new speakers (and DWMs) set up properly. I have failed so far. One problem may be that my speaker cables are not long enough without the extra room I gained from having the external crossover box. That and the fact that the imaging is still firming up with break in.
I am not sure if it is the setup itself that is causing the midbass dip. It does lift the deep bass while not exciting the narrow measure room resonance which should be about a 80hz and 160 hz resonance for a 14 foot wide room. In my setup, while the deep bass does pop up the mids (once adjusted in relative volume) are ok with a bit of a dip at the crossover.
Ignore the measurement past 1khz since the calibration curve I used here didn't extend that far.
Just to clarify, Satie...
Your experience is that moving from five feet to eight-ten feet (from front wall) does not reduce mid or upper bass relative to lower bass?
I assumed this was an artifact of the base wavelengths rather than just a room anomaly . I assume a lot though and have zero training in the field. Always glad to learn.
Moving the speakers away from the front wall reduces midbass and deep bass but not in such a big way and not the one significantly more than the other. The lean midbass you observe was there before too wasn't it? It just got worse moving the speakers into the HK/Limage position.
You had a toe in for the speakers before that would have allowed the resonance from the width of the room to get excited. That would have contributed to midbass with the primary 80 hz resonance of the 14 ft wide room and the first harmonic at 160hz. In the HK/Limage setup there is no excitation of that mode because the sidewalls see the dipole null and no direct radiation till further down in the room. You can test it out with the toe in angle- as you go up in toe in you should notice less deep bass and more midbass as you decouple from the long room length and couple the shorter one.
The other thing is the degree of bass loading provided by the sidewalls. That increases as you push the speakers towards the sidewall to reduce the width of the slot between them. That reduces the degree of dipole cancellation on that side so leaves more of the bass driver's tuned resonance peak uncancelled at the listening position.
The midbass enhancement from the DWM should be well beyond enough to fill in for both the loss of the room width's resonance peaks and for whatever else had been reducing midbass in your room.
On another note, your 3.7i is still rather new and if you hadn't been playing it at lease breaking levels then it will take some time to loosen the midbass.
Thanks Satie,
I was referring to the measurements with my IIIa's. I am still just breaking in the new guys.
In my room, I got the most even upper bass and mid bass at about five feet from FW. In other words, conventional setting.
Twelve inches or so from side wall with minimal toe in with the speakers almost to mid room I got pretty much flat bass from 50 to 25 hz but about a five to seven db suckout from 160 to 80. The DWMs fill this gap perfectly.
If I toed the speakers in I got muddy sound. (Interestingly this does not seem to be the case so far with the new speakers)
You might try Sewell Direct for terminated 12 gauge cables...They are really cheap-so they are perfect to experiment with. 10' terminated costs $15 a pair. 6' $10 a pair. 15' $20 Silver back line...Not bad stuff and they do have depth and are well made.
That is a really good idea, Utley.
What is good about them is that there are no expectations, no risk and you just keep plugging things in and out. They will function until you really find what you want. The strand count is high and they are 99% oxygen free (big deal)but the maker is not throwing out any cliches. 'Whatever' as they say! I play with them on the 1.7's while keep on trying different positions. They image well enough but after two nights of Monteverde's Vespers live, with GREEN MOUNTAIN PROJECT in the Sainte Jean Baptiste Church NYC and experiencing sheer bliss, of (position and depth of individual voices each voice with their own character and timber making harmony and counterpoint as natural as breath - 15 magnificent singers; you almost want to give up digital hi fi. I put on some fine Harmonia Mundi CD of the same pieces- meaning I expect to be moving things around for months and searching for a new preamp or will just go back to vinyl The sounds was heavenly and I could have listened many hours-without ever tiring.
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