Hi Todd,
What distance from the side / rear wall worked best for you?
Hi Todd,
What distance from the side / rear wall worked best for you?
Originally Posted by toddalin
Yes, Todd if you could give us a simple sketch of teh layout with a couple of dimensions it would very cool to better understand your room.
Widget
I'm sure your DIY wave guide and back treatments have gone a long way to change the nature of the interaction between the ESS AMT tweeters and your room and align the imaging with the more traditional type of sound that many of us prefer.
Widget
Room is 26 feet across and speaker centers are at 7.5 feet so (26 - 7.5)/2 = 9.25 feet. Room is symetrical.
Cabinets are up against the front wall and are 30" deep.
Room is 16 feet deep and speakers are 2.5 feet deep and up to the wall so baffles are at 2.5 feet.
Couch cushion (sweet spot) is 10.5 feet out from speakers so 16 - 2.5 - 10.5 = seating is 3 feet from back wall. When I lean forward, away from the cushions, things get better. The speakers are toed in to the sweet spot using a laser pointer.
Front wall is 16 feet high and back wall is 7.5 feet.
https://cimg0.ibsrv.net/gimg/www.cor...58107c6978.jpg
https://cimg3.ibsrv.net/gimg/www.cor...4437e9614e.jpg
https://cimg7.ibsrv.net/gimg/www.cor...1cf11fb6a8.jpg
There is an account of my experiences with sound stage and imaging.
Measurement of enclosure locations
Like many here l found early on that small adjustments to the position of the enclosures. made a clear difference to the sound stage, size and focus of the image. But it was confusing with the number of variables so l started writing down the x z coordinates on a sheet of paper on top of each enclosure. This was with bookshelf loudspeakers on stands including vertically aligned monitors, a pair of 4311’s and a MTM tower monitors. Later on l pursued a more exacting approach with the much larger diy systems.
It’s tricky to make a definitive comparison but a large baffle with a large radiation area delivers a more in your room presentation than a narrow tower system. If it sounds like it’s in your room then that’s a huge advantage if you’re after an immersive presentation.
Effects of Toe in
I then realised that precise measurements required a tape measure to accurately adjust the toe in angle and exact distance from the front wall and side wall. It was at this stage that l reasoned then the side wall reflections and the angle of the reflections were critical to the precision of any imaging. This also had the effect of changing the blend of the direct and the indirect sound at my listening position. With some adjustments l could get an almost seemless soundstage.
Effect of accurate levels
Sometime later l started to investigate the driver levels and l found a switched volume attenuator has a more stable centre image. Originally with a Tandy analogue spl meter l then found calibration of the dreaded L pads produced a more coherent sound stage. I did this empirically to within 1/2 a db with the analogue scale by matching the level right on the zero db marker. Measurements in the 600-2000 hertz range were effected by being anywhere near the front or side of the enclosure.
I subsequently found on jazz genre’s individual instruments were rendered more realistically. It was a more vivid, solid and defined image of a trumpet and saxophone. Not all recordings are created equal however. Kind of Blue does work despite the age of the recording.
Room compromises
Sometime later l changed to a new room that was 4.7 m x 3.8 m. It was heavily furnished and had heavy drapes. I had the enclosures about 2.7 metres apart but l again had to sit further back than was optimal for political correctness.
The rendering of depth was impressive particularly on a well produced recording. The album Toy by Yellow is interesting.
https://en.m.wikipedia.org/wiki/Toy_(Yello_album)
I found opening up the soundstage a compromise between side wall image impact and the centre spacing. If your room isn’t wide enough for large enclosures it’s a bit of a compromise. I’ve experienced this problem with the DD67000.
Summary
What this all this boils down to is getting the absolute best out of what you have in your particular situation. I don’t believe with a sheer diversity of rooms and systems in an online discussion that there are any absolutes as far as loudspeakers are concerned. More importantly it’s your own auditory experience that matters. Your ears are the final arbiter.
Edit. In the case of the legacy systems using the 2308 your ear height (or the loudspeaker height) should be such that the bottom edge of the lens is at ear hight or slightly above. This makes an audibly difference to the sound stage and imaging. Measurements highlight the sensitivity of the crossover region to height at the listening
position.
Accurate driver level matching is very important between channels. Over the 20-20,000 frequency range subtle differences in frequency response level are audible. Just check out phono Riaa stage reviews. A +- 1.00 db is deemed unsatisfactory. You can hear this in comparisons because the ear is sensitive to broad shifts in frequency ranges. Therefore if one loudspeaker does not track in close continuity with the other it will impact on your stereo image in terms of tonal solidity of images and image sharpness.
Last edited by Ian Mackenzie; 02-04-2024 at 09:13 PM. Reason: Grammar and editing a shorter post
Hello Toddalin
Looking at your photo's you still use your L200/300's?? in your HT? Looking at you side wall and mirror reflection are the side and backwall windows with blinds? Looks like the upper triangle has some kind of material covering and blackout blinds below?
Rob
"I could be arguing in my spare time"
I'd love to take you up on that some time. I'm in Long Beach. Conversely, you could have a listen to my system as well.
Regarding your comments about processing for time aligning horns I'll disagree though. The design I put together for the full Cogent systems I built with Rich and Steve has all of the drivers very close to physical alignment and the hardware is such that they are to be fine tuned to their room. Both physical alignment and focus can be adjusted for any listening distance. In my own installation the built-in bass horns are a 5-6 msec behind the midbass, but most people would never notice that in the bottom octave. My system was always designed for full analog so digital correction has never been an option.
When properly adjusted they disappear and create a great image. My own room is small but well treated: not fully dead but enough diffusion and diffraction for really crisp clear sound.
One this I haven't seen mention of as I've scanned this thread is soundstage extending beyond the speakers. If a signal is sent equally to both speakers in phase it will be centered. If phase is reversed in one channel the resulting phase cancellation will shift the image outside on the speaker with the correct phase. If can happen naturally in well engineered live recordings just from the natural room interactions, but it can also be done in the studio.
eso
30Hz Bass Horns/K151, Custom mid bass & midrange horns/Cogent DS 1428 & 1448 field coil drivers, Fostex T925a tweeters.
Hello eso
Yes Q sound comes to mind for the studio where they use phase to steer images. Roger Waters Amused to Death comes to mind.
Rob
"I could be arguing in my spare time"
No, I really don't except for the occasional comparison. The imaging on the L200/300s is terrible, but they are definately too far apart to image properly.Hello Toddalin
Looking at your photo's you still use your L200/300's?? in your HT? Looking at you side wall and mirror reflection are the side and backwall windows with blinds? Looks like the upper triangle has some kind of material covering and blackout blinds below?
Rob
One side (behind the Super Reds is mainly covered in windows as is the wall behind the couch. The window blinds have "accordion", black-out material for the projector. The angled window behind the Reds has a sheet of black visqueen to keep out the light.
The side wall opposite the Reds is open to the hallway and dining room for the last ~6 feet as is the back wall behind the couch for ~6 feet.
https://cimg3.ibsrv.net/gimg/www.cor...481987194d.jpg
https://cimg2.ibsrv.net/gimg/www.cor...73759e29d5.jpg
https://cimg6.ibsrv.net/gimg/www.cor...10fe8aa9ef.jpg
https://cimg3.ibsrv.net/gimg/www.cor...e5ed37bb1a.jpg
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Hello Toddalin
Nice room! So they are blinds. Do they also work as "acoustic curtains" not knowing how they are made. Are they heavy fabric? That gives you more flexibility to make the room "Live vs Dead" by simply opening closing or adjusting the blinds. Assuming they are adjustable like typical window blinds are.
Do you use them that way at all or are they keep that way all the time to help darken the room?
Rob
"I could be arguing in my spare time"
Hi Todd,
I think what you have described here and with your pics makes a lot of sense! Your room has the size and virtues like the ceiling to create imaging particularly with a dipole situation.
As l mentioned in my own post and since seeing Eso & your room the diversity of rooms and different systems makes any comparison type discussion about accepting the comments by each user. There really isn’t a qualitative discussion to be had. It’s more about the user describing the imaging in a set format a bit like what l posted earlier.
Edit : l have visited to hear Todd’s system
Last edited by Ian Mackenzie; 02-05-2024 at 01:25 PM. Reason: Added information
They are thick enough and the pleats break thing up such that they do serve as acoustic curtains. But I do leave them down and the room is already more lively than I would like. I've thought about having cork placed on the angled ceiling.Hello Toddalin
Nice room! So they are blinds. Do they also work as "acoustic curtains" not knowing how they are made. Are they heavy fabric? That gives you more flexibility to make the room "Live vs Dead" by simply opening closing or adjusting the blinds. Assuming they are adjustable like typical window blinds are.
Do you use them that way at all or are they keep that way all the time to help darken the room?
Rob
If you listen to one of my videos and you listen to the YouTube direct version, you get a very good sense for what the room is adding and taking away (e.g., floor bounce).
https://youtu.be/krlBTPPehm0
https://youtu.be/GXE_n2q08Yw
Any comments about how you progressed to improve the imaging would be appreciated.
For example l mentioned the level matching and location measurements. My network is more advanced & an acquaplas dusted diaphragm runs full range. This improves the blending of the drivers. Incremental improvements can add up to significant refinement in performance.
Some details on the construction of my room... The bass horn mouths include irregular surfaces to break up any mid and high frequency reflections. Also, the while it looks like the equipment racks are connected the the bass horn mouths they are actually suspended on separate frames fully decoupled from the bass horns to avoid as much interaction as possible, and the supports for the equipment include a bunch of upholstered 2" fiberglas absorption to help minimize affecting turntable playback.
Millwork on the rear wall are pieces in several widths, depths and angles. The thinking is that by just breaking up waves and bouncing them against the gabled ceiling the reflection off the ceiling just sends them into the rug and absorbs them. Even the self for CDs on top on the record cases is irregular (I refer the that shelf and the stealth fighter shelf)
Not visible in the build on the record cases. The backs of the cases are only covered with upholstery and the space behind them is stuffed full of R-39 Insulation: They are effectively bass traps.
After setting up the room I also installed some 2" rigid fiberglas panels where the 1st reflections from the mids would hit, and some paper pulp diffuser panels on the ceiling.
And I cannot overstate how effective good room treatment is when it comes to good stereo presentation.
eso
30Hz Bass Horns/K151, Custom mid bass & midrange horns/Cogent DS 1428 & 1448 field coil drivers, Fostex T925a tweeters.
Getting spacing/toe just so (big time),
Cutting off the rear wave from the Heils,
Adding the rear reflector half round to the Heil (big time)
Time alignment of the drivers
Foams on reflective surfaces (top of speaker, bottom of Heil)
Reduction in crossover/driver "overlap"
Getting the relative driver volumes just right (resistor values). The L-pads are run at max and could be removed.
I had been working on these for years, then after something I did (don't remember) Carlos Santana's guitar was suddenly standing right there "proud" in the room like never before. It only got better after that.
Most current version of crossover (subsequent to any videos).
https://cimg3.ibsrv.net/gimg/www.cor...84e78f1ce0.jpg
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