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aechmea

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aechmea last won the day on January 22 2014

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About aechmea

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    Aechmea recurvata

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  1. Welcome James Craig. Craig James or James Craig; sounds as though you are either a celebrity economist or a tall ship. Either way, welcome. There is a lot of good stuff here and helpful people. Enjoy the site. Don't forget to tell us more about your system and participate often.
  2. It seems that many people have their subs near the main speakers. I think that is a big mistake. In my experience, in my room, this was the worst position that I tried; a monumental suck-out of everything below 50Hz. I eventually solved my problem by placing one sub behind the chair. Trial and error with a dollop of intuition seems to be what is needed. I like 2 subs since that allows much more flexibility for placement. I did find a good position for a single sub but that was in a weird place out in the open spaces of the room, but, that was inconvenient for room use. EQ is OK I suppose but it can only fix a small number of problems since more energy poured into a phase cancellation produces precisely nothing. IME its all about positioning. And you really have to measure. Edit: Don't trade big for two small. Just get another big!!
  3. (Sir Francis) The Drake and Smith are spot on. I reckon that positioning subs is 90% of the deep bass problem/solution. Its the old real estate tenet "Position, position, position". My 2 subs would appear to be randomly placed to the casual observer, but they are where they are to give a pretty even response combined with the mains. One position was better, but had a sub right in the walkway so a compromise was required. Still good though. It took a while to get there, since none of the recommended/normal/common positions proved to be any good. Be outrageous if need be because there are some great results to be had.
  4. Hi G I am curious as to what the cable is between the mid/ribbon panel and the bass panel. Is it just a normal speaker cable? or is it a speaker cable with special connectors? or is it some proprietary construction? and ... What way does it "flow", power amp to mid/ribbon to bass panel or power amp to bass panel to mid/ribbon? and ... Does anyone know what the XO frequency is between mid range and bass. [Trying to work out whether these could be active bi-amped fairly easily. I already have a DEQX , spare Magtech and spare (quality) speaker cable. So would be no cost to me if it were possible.] Thanks
  5. I have 20.7s, 2 subs and a DEQX and have had for many years now. The DEQX has function other than plain old EQ. One important feature is "speaker correction" which is a form of DSP/EQ to correct for timing and amplitude anomalies in the speakers (and subs) themselves. This is completely independent of the room and is/can be applied as a filter irrespective of the room that the speakers are in. It does not have to be re-done. If one can find and use a better anechoic space for "speaker" measurement then you might consider doing it again. The cross-over and filter slopes etc. function for active multi-amp systems is not applicable for 20.7 owners. 20.7s have some sort of fancy/weird inbuilt passive XO that has had its access denied (except with an axe, if one is game). With the DEQX you can choose to hi-pass/low-pass to subs wherever you like and choose whatever filters and slopes that take your fancy. Delaying mains or subs, adjusting amplitudes etc etc; there is a multitude of tinkerings available and can keep one occupied for years. Then we have the room and the way that the speakers are positioned and react with the room. DEQX (or any other device) cannot influence cancellations that give the bass freq response its mountain range look. Troughs are like black holes; pouring more EQ energy into a trough makes no difference at all. Bass EQ via a DEQX is not automatic; one needs to make their own decisions, apply EQ and see what the result is. Repeat as required. Almost all of my bass response manipulation was done by positioning. This is fundamentally important. One can achieve excellent response by carefully placing the subs, then cut the tops off a peak or 2. It all takes time, some knowledge of acoustics and a dollop of intuition/luck. Rather than randomly try various positionings, I made an Excel spreadsheet that calculated all the path differences from direct sound path length versus first reflection path length from all the room boundaries then converted those distances into wavelengths/frequencies and whether they were in/out of phase. Different to all of those "modal" calculators that assume that there is only 1 reflection, that it happens to create a standing wave and that one is sitting in its peak or trough. I did find that http://www.hunecke.de/en/calculators/loudspeakers.html was quite insightful even if only a very very approximate representation. At least it suggested to me that I might be better off with one sub at the back of the room. I tried it; it measured well enough for me, so I left it at that and added a bit of EQ to tidy up. Since then I have added a warehouse full of semi-rigid and rigid fibreglass to kill reflections coming from the back wall (behind the chair) and put some diffusion panels on the front wall to spread the back-wave of the Maggies somewhat. [Don't forget that Maggies need some sort of triangular buttress support. Those tiny T-feet really are hopeless.] Sorry, got a bit off the track there, but hope it helps someone. Finally, back at the DEQX. It is not as automatic as a lot of people think. Sure the software generates the filters but only after a knowledgeable person traverses the step-by-step procedure, feeding it knowledge-based measurements, numbers and decisions. There is no "push this button and everything will be alright". Not even close.
  6. I suspect that all of these "measurements" from almost everyone are either dodgy or are the best possible figure under the most conducive of conditions. Most nominal 4-ohm speaker manufacturers use 2.83volts because that secretly equates to 2 watts not 1, thus giving an inflated (better) sensitivity number. The corresponding 1 watt @ 1 metre is 3 dB less. Then, of course, is how and where they have been measured. My 4-ohm mains are advertised as 86 for 2.83v, but that is really 83 for 1 watt. Compare that with a German magazine that measured them at 77dB. What's going on there; sumpin' just ain't right. I can't believe either number. In the OP, the 92dB speaker is much more sensitive ... 92 - 81 = 11dB = approx 10 times more sensitive (dB is a logarithmic ratio; dB = 10 log(p1/p0)).
  7. My biggest bass problem was that there was a SBIR cancellation between the first back wall reflection and the direct wave. Solved with positioning the subs; particularly with one on the back wall. One wouldn't know that there were subs in operation.
  8. An older image when I had bi-amped 3.6R Factory T feet riveted to square tube. Cones on bottom of tube thru carpet to concrete. Tabbed across an inch or so to align vertical tube with existing screw holes Verticals attached with existing Screws Total cost = the cost of 8 fat rivets, thanks to father-in-law who had the tube, tools and the expertise. ------------------------------------------ And just in case one is curious about absorption here is the rear wall. Following the Linkwitz idea that sound should pass your ears once and never return. 4 x tube traps, 2m high x 450mm diam (2 out of frame) 2 x 2400 x 1200 x 100 semi rigid fibreglass sheets 2 x 2000 x 1200 x 100mm fitted into window alcoves 2 x 2 seater lounge chairs 2 x 1200 x1200 x 100 leaning against lounges All removable in a few minutes ie no permanent damage to room.
  9. Absolute necessity, IME. In my case, home-made tubular steel triangular buttress frame coupled using spikes to the concrete slab floor. Made a hellava difference.
  10. Forget the 2000 remaster (DR7), it has been severely compressed; find yourself the original 1985 CD (DR14) or the 1994 version (DR13) Like a lot of early CDs there are a multitude of pressings made/issued in various parts of the world. Mine happens to be one made in Japan (Sanyo ) for Germany and has a catalogue number of 610 195-222 CID 101 Apparently one of the original CID 101 versions has different tracks on the CD making it close to the LPs, but the booklet/cover lists the normal CD tracks and then to confound it further a couple of other tracks are missing and one is shortened. The problem is that the normal CD tracks already run for 72 minutes so something had to be left out to retain a single CD. Now look what you've gone and done. I'm off to find the other CID 101 with the other couple of LP tracks on it! ----------- Edit; it appears that the CD with alternative tracks may be easier to find than I first thought. Some French, US and Canadian CDs have that particular set of tracks.
  11. Pretty much what everyone else has said, but I will add my comments in support ... The L and R are so different that the room must be (almost) all of the problem. The combined response has a broad shallow dip from 120 to 450Hz. There is a lot of info in this range. Think voices, both male and female, left hand of the piano and probably stuff like cello ... You are missing the richness but as a consequence you are still hearing the brash bits at higher frequencies. The dip is very prominent in the L channel compounded by the lump at 50 and another at 500. If you can fix the L then you might be getting close. Trial and error is required. Lift them, twist them, move them, get the lounge out of the way (at least temporarily). At the moment both L and R are pointing straight ahead. You are actually listening off-axis. Not many speakers are "good" off-axis. Like others have rightly said, rotate them to point roughly at the listening chair. This also changes the reflection angles off the front and side walls which could be of benefit. Positioning is a powerful tool and even though an in-room response will never look perfect, it could be all that you need. When you have exhausted "positioning" improvements then a few dollops of EQ (done with a gentle hand) to lop off the remaining peaks and boost the shallow wide troughs will help a bit more. [I reckon that it's the lounge that did it! Blunt instrument trauma.]
  12. It's important to have an amp that can cope with your speakers. Many speakers have low sensitivity and/or low impedance and/or have wildly fluctuating impedance. Most people underestimate the grunt needed to reproduce music at realistic levels via naughty speakers. Choice of amp is dictated by your speakers. It may take several iterations to find a suitable amp. If your choice is between two amps that are both "suitable" then they should both be operating within their safe limits and should be pretty much indistinguishable. Amps pushed beyond their comfort zone don't sound nice. That's when they really start to sound different. In my experience the differences between DACs is also pretty minimal. Lets not forget the elephant of hifi. Positioning within the room of speakers and chair, and the room geometry and its acoustics are even more important to get right than equipment. Easier to buy a bright new shiny box though.
  13. Yep; mastered for train/bus/car travel Mine is the 24/88 download, which I bought due to hirezedness and because of the rave reviews. I may have played it twice. [Edit; it has the same DR values as the CD]
  14. I have the Windows paid version of dBPoweramp CD Ripper (so I can do HDCD expansion). I have had a look at the Options. There is nothing there that would cause a resample. However, the encoder settings box has the option to add DSP to the encoder, one of which is "Resample". No idea about Kodi or any of the audio layers/drivers.
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