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Post by creimes on Jul 8, 2022 13:39:49 GMT -5
Yes, supposedly they are working on a replacement for the G2 model. You'd think that it would have been all designed BEFORE they ended the G2 model. I agree a DAC should be built in but I'd also settle for a stand alone DAC BUT I'm not holding my breath for any earth shaking stereo equipment. As much I have always really enjoyed my Emotiva products there are just so many other great choices out there these days  |
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Post by DavidR on Jul 8, 2022 15:22:54 GMT -5
Yes, supposedly they are working on a replacement for the G2 model. You'd think that it would have been all designed BEFORE they ended the G2 model. I agree a DAC should be built in but I'd also settle for a stand alone DAC BUT I'm not holding my breath for any earth shaking stereo equipment. As much I have always really enjoyed my Emotiva products there are just so many other great choices out there these days
My XSP-1 G2 is a very nice Pre and I would look into an upgraded version for sure.
The only reason I still use a BillD modified C-1 Carver Pre is for the 115VAC receptacles on the back. I need it for the 901_II EQ. Very convenient but would ditch it if I upgrade the XSP-1 on my main system.
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Post by leonski on Jul 8, 2022 19:59:45 GMT -5
GOTTA have those Bose, too?
And while you're at it? check ou the Parasound P6 preamp. DAC? Balanced I/O? Sub Out? Sub level? Tone controls?
This is a full-featured piece which may be suitable to replace your XSP g2?
For full disclosure? I have th P5 which is essentilaly the saem as the P6 but without the displany and a different DAC section.
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Post by DavidR on Jul 9, 2022 7:48:51 GMT -5
I took a look at the P6. I wasn't moved. I almost never use tone controls and don't need a sub. The business end of the XSP-1 has so many more options I/O.
If I find a replacement the XSP-1 G2 will replace the C-1 and a new Pre would do duty in my main system.
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Post by leonski on Jul 9, 2022 17:36:03 GMT -5
Doesn't the C1 have the Sonic Holocaust system by Bob?
It'll be nearly impossible to replace that unless you are a fan of Polk SDA speakers....which arrive at the same system
by another means...
I'd love to compare I/O options......I'm not short of 'em but do NOT have an overly ambitious system, either.
But I DO have a 4-into-1 optic switch which feeds the SOLE optic input on my P5.
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Post by DavidR on Jul 9, 2022 18:00:14 GMT -5
Sonic Holography. Used it one or two times. To me it diminished the stereo effect. The C-1 is nowhere near as quiet as the XSP-1 which is dead silent even a full volume.
I'm a fan of Acoustic Research speakers.
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Post by leonski on Jul 9, 2022 20:00:24 GMT -5
You could be a fan of WORSE speakers, that's for sure. AR got the ball rolling a long time ago on the 'small' speaker which also turned out to be quite a bit less sensitive, which was OK, since solid state happened JUST IN TIME to fill the power gap.
who was it back tha? Hafler? Kloss? I don't remember who was the basic 'inventor' of the acoustic suspecnsion speaker. I think Kloss was in the mix but another name, too, wth which I'm less familiar....
Polk SDA speakers use a similar system to 'cancel' by using a 2nd speaker in each enclousre the inter auril distance apart......about 6 inches.
I wanted to borrow the Sonic Holocaust generator from a dealer at that time, but could never get the loan.....
I DID however, experiment at lot with what came down the pipe as DynaQuad. Built the 'adapter' and later figured it out and went AlaCarte.....It was wonderful on LIVE music but no better on studio stuff....
BTW? I owned the M400t amp for a long time....Wonderful, compact and tended to run fairly cool. But later problems and what was a Chinese Puzzle Box level of construction baffled me when I went in
to find out what had failed.....Probalby had lerge choke in the PS.....Or amybe the Trial / SCR......whichever it was.....
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Post by mgbpuff on Jul 10, 2022 6:44:07 GMT -5
You could be a fan of WORSE speakers, that's for sure. AR got the ball rolling a long time ago on the 'small' speaker which also turned out to be quite a bit less sensitive, which was OK, since solid state happened JUST IN TIME to fill the power gap. who was it back tha? Hafler? Kloss? I don't remember who was the basic 'inventor' of the acoustic suspecnsion speaker. I think Kloss was in the mix but another name, too, wth which I'm less familiar.... Polk SDA speakers use a similar system to 'cancel' by using a 2nd speaker in each enclousre the inter auril distance apart......about 6 inches. I wanted to borrow the Sonic Holocaust generator from a dealer at that time, but could never get the loan..... I DID however, experiment at lot with what came down the pipe as DynaQuad. Built the 'adapter' and later figured it out and went AlaCarte.....It was wonderful on LIVE music but no better on studio stuff.... BTW? I owned the M400t amp for a long time....Wonderful, compact and tended to run fairly cool. But later problems and what was a Chinese Puzzle Box level of construction baffled me when I went in to find out what had failed.....Probalby had lerge choke in the PS.....Or amybe the Trial / SCR......whichever it was..... Edgar Villchur of AR was the inventor of the acoustic suspension speaker. Bob Carver's Sonic Holography (which used a little out of phase left signal in the right speaker and vice versa in the left channel to cancel left information going to the right ear and vice versa) actually worked startling well, but it required you to set at the equilateral triangle spot with vice-like head stability. |
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Post by DavidR on Jul 10, 2022 9:29:00 GMT -5
Edgar Villchur of AR was the inventor of the acoustic suspension speaker. Bob Carver's Sonic Holography (which used a little out of phase left signal in the right speaker and vice versa in the left channel to cancel left information going to the right ear and vice versa) actually worked startling well, but it required you to set at the equilateral triangle spot with vice-like head stability. All of the best audio engineers worked for AR at one time or another. Most were from MIT. Many went on to form their own speaker/audio companies. Villchur quickly built the company to become the 2nd largest speaker company worldwide. His AR3, and with the expertise of Roy Allison, the 3a became #2 on the list of the top 12 speakers of all time. They are highly sought after today (me included). The sale to Teledyne in 1967 only brought more innovation and some fantastic speakers. Sadly, their marketing sucked and they were late to the college craze party with speaker companies from past employees beating them to the finish line. |
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Post by leonski on Jul 10, 2022 23:04:49 GMT -5
Polk SDA (new ones available) and the Sonic Hologram use the same priniclple. Carver did it all electrically while Polk did it with a pair of speakers the same distance apart as your ears.... And used a speaker cable connecting the L / R speakers. And my understanding is that it is not phase, but common informaiton canceled out between sides.....Is that phase or just time delay? Or just a restate of the same thing? I ran those experiments with Dynaquad, but more sophisticated. Terrific for live, and not hugely sensitive to 'sweet spot'...... Each channel has information from the other side. I have trouble putting it into words, but take the right channel.....all you want is right information? But you have 'left' mixed in. The key is the time delay between the left and right ear.....I think that may be whet gives the system its sensitivity to listener position. I've heard the sensitivity of Hologram to position. I still wish I'd had the opportunity to experiment when it was new.... forum.polkaudio.com/discussion/185530/challenge-polk-sda-vs-carver-sonic-holographyI can't vouch for the link, but others apparently have had similar questions about what they call 'SH' and the Polk SDA system..... |
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Post by mgbpuff on Jul 11, 2022 6:23:07 GMT -5
"Sonic holography", as described in U.S. Patent 4,218,585 was first incorporated in the Carver C4000 preamplifier. It enhances stereo imaging by introducing a delayed and equalized signal from the right channel at the left loudspeaker to cancel the signal from the right loudspeaker at the listener's left ear (and vice versa).
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Post by KeithL on Jul 11, 2022 9:49:57 GMT -5
Dynaquad was a really ingenious idea... The way the signal is processed is quite simple and only involves a few inversions and summations... RB = (0.8*RF) - (0.4*LF) LB = (0.8*LF) - (0.4*RF) (Those numbers are approximate. It's pretty simple to figure out the exact values but I'm too lazy right now.) The cool part is that the passive version runs the rear speakers from the same stereo amplifier that's running your front channels... And the circuitry itself is a single 10 Ohm resistor (for 8 Ohm speakers). Note that it must be a REALLY BIG power resistor since it will be dissipating as much power as one of your speakers. (You can also build an active version, that uses a separate amplifier for the rear speakers, pretty easily from about $20 worth of parts.) Dynaquad actually works remarkably well for content that has lots of complex ambience information (like many live recordings.) Carver's Sonic Holography does work on the same basic idea - but the electronics are a lot more complicated. It was incorporated in several of their preamps and receivers... and the separate C-9 had one extra option switch. It involves a lot of filters, delays, phase shifts, and summations... all done with LOTS of separate op-amps... (Obviously it could be done these days with DSPs.) You can download the Service Manual for the Carver C-9, which was the separate unit, and includes both schematics and block diagrams. (It's pretty easy to find a copy on one of the sites that offer free manuals if you Google it... ) (They also turn up on eBay from time to time.) I owned one once. I found the effect to actually be quite impressive with some content., The "catch" was that it was VERY dependent on your seating position. You literally had to sit DEAD CENTER - WITHIN ONE OR TWO INCHES - for the full effect. (Apparently it was effectively simulating the binaural effects of "head effect" pretty well.) And, while "impressively cool", it was also somewhat artificial, so I got tired of it pretty quickly... But it might be interesting to compare it to modern "surround simulations"... (And note that it does only use your regular pair of stereo speakers.) Polk SDA (new ones available) and the Sonic Hologram use the same priniclple. Carver did it all electrically while Polk did it with a pair of speakers the same distance apart as your ears.... And used a speaker cable connecting the L / R speakers. And my understanding is that it is not phase, but common informaiton canceled out between sides.....Is that phase or just time delay? Or just a restate of the same thing? I ran those experiments with Dynaquad, but more sophisticated. Terrific for live, and not hugely sensitive to 'sweet spot'...... Each channel has information from the other side. I have trouble putting it into words, but take the right channel.....all you want is right information? But you have 'left' mixed in. The key is the time delay between the left and right ear.....I think that may be whet gives the system its sensitivity to listener position. I've heard the sensitivity of Hologram to position. I still wish I'd had the opportunity to experiment when it was new.... forum.polkaudio.com/discussion/185530/challenge-polk-sda-vs-carver-sonic-holographyI can't vouch for the link, but others apparently have had similar questions about what they call 'SH' and the Polk SDA system..... |
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Post by KeithL on Jul 11, 2022 9:59:16 GMT -5
Just FYI... "Phase" and "time delay" are different ways of expressing or viewing the same thing... When you phase shift a signal you delay it and vice versa. (Technically you can also advance a signal in time by applying a leading phase shift - although the practical ramifications of that are... interesting.) However phase is related to wavelength and frequency while time is a fixed number. So, if you apply a certain time delay to a signal containing multiple frequencies, the phase shift caused by that time delay will be different at each frequency... And, in order to apply the same number of degrees of phase shift to different frequencies, you must apply a different amount of time delay at each frequency... (So, for example, in order to apply the same phase shift across a band of frequencies, you must apply a time delay that VARIES WITH FREQUENCY.) (And, in order to apply the same time delay across a band of frequencies, you must apply a phase shift that varies with frequency.) Polk SDA (new ones available) and the Sonic Hologram use the same priniclple. Carver did it all electrically while Polk did it with a pair of speakers the same distance apart as your ears.... And used a speaker cable connecting the L / R speakers. And my understanding is that it is not phase, but common informaiton canceled out between sides.....Is that phase or just time delay? Or just a restate of the same thing? I ran those experiments with Dynaquad, but more sophisticated. Terrific for live, and not hugely sensitive to 'sweet spot'...... Each channel has information from the other side. I have trouble putting it into words, but take the right channel.....all you want is right information? But you have 'left' mixed in. The key is the time delay between the left and right ear.....I think that may be whet gives the system its sensitivity to listener position. I've heard the sensitivity of Hologram to position. I still wish I'd had the opportunity to experiment when it was new.... forum.polkaudio.com/discussion/185530/challenge-polk-sda-vs-carver-sonic-holographyI can't vouch for the link, but others apparently have had similar questions about what they call 'SH' and the Polk SDA system..... |
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Post by KeithL on Jul 11, 2022 10:25:01 GMT -5
Not counting phase shift... If you mix the channels together then you "reduce L/R separation". But... if you mix an INVERTED signal from each side into the opposite channel... you can increase the separation PAST 100% . You can basically build a box with a knob that is marked "mono" at one end, "stereo" in the middle, and "extra wide" at the other end. A normal stereo image has some mixing between the channels... by cancelling signal you are reducing this "unnaturally"... And, if you do it too drastically, the result can sound really odd... and you also tend to lose most of your bass... (And, if you start with a signal that has near-full separation, the effect is even more dramatic and unnatural.) However, when done in moderation, or at only certain ranges of frequencies, it can effectively "spread the sound stage out past the sides of the speakers"... This is what Polk is doing... at carefully chosen levels and ranges of frequencies... and probably with some phase shifts beyond simple cancellations. (There are processing plugins specifically designed to do this... and a few "little black boxes" include it as an option as well.) Polk SDA (new ones available) and the Sonic Hologram use the same priniclple. Carver did it all electrically while Polk did it with a pair of speakers the same distance apart as your ears.... And used a speaker cable connecting the L / R speakers. And my understanding is that it is not phase, but common informaiton canceled out between sides.....Is that phase or just time delay? Or just a restate of the same thing? I ran those experiments with Dynaquad, but more sophisticated. Terrific for live, and not hugely sensitive to 'sweet spot'...... Each channel has information from the other side. I have trouble putting it into words, but take the right channel.....all you want is right information? But you have 'left' mixed in. The key is the time delay between the left and right ear.....I think that may be whet gives the system its sensitivity to listener position. I've heard the sensitivity of Hologram to position. I still wish I'd had the opportunity to experiment when it was new.... forum.polkaudio.com/discussion/185530/challenge-polk-sda-vs-carver-sonic-holographyI can't vouch for the link, but others apparently have had similar questions about what they call 'SH' and the Polk SDA system..... |
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Post by leonski on Jul 11, 2022 14:38:42 GMT -5
As usual, keith, you don't make things more clear. Sure......time / phase are different ways to express the same thing. Good example? My Maggies have a 6db and 12db crossover......So the 2 drivers are 90 degrees apart. And can be corrected thru toe-in where one of the drivers is a little further from the listener than the other. It is, after all, a 2-way design......And that corrects the problem and helps imaging. These are conventional crossovers, so the 'effect' is not even across the bandpass.... As for SH and SDA. They do the same thing by different means. Yes, Carver went all-electronic and may not have actuallly helped his case. Polk, OTOH, uses wiring between the speakers and a 2nd driver over the frequency range of interest. The effect is not very important at bass frequencies. I don't know how high it extends. But for sure? the DISTANCE between the drivers in each enslosure is key. And is the same (give or take) as the distance between your ears. The idea is that in a stereo recording, Left and Right are generally not 'pure'. Left has some right and the reverse is true. The wiring / driver allows you to subtract one from the other and recover true left or right. Can this sound weird? I'd go listen somewhere to the new generation of SDA speakers. www.crutchfield.com/shopsearch/POLK_SDA_speakers.htmlFrom Crutchfield. good view of the mid / high driver array showing distance. You can refer to, if you can find it, the original Carver advertising for the SH. He makes it pretty easy to understand. forum.polkaudio.com/discussion/186715/sda-2b-crossover-upgrade-do-i-have-this-rightSchematic of SDA system......I hope its right! Keep in mind that the physical distance between the 2 drivers involved is important. As for dynaquad? I just Junked Out the Schematic. I had a 2nd amp I connected the rear effects speakers from PLUS to PLUS (common ground amp) in series. Some experimentation here, since you had a couple choices. I used the VC on this amp as front / rear balance. I also put in a 10ohm / 5 watt power resistor in place of the correct speaker placment. That resistor never got even warm. And the effect was dazzling. On LIVE material, you were in the middle of the audience. And some output came from behind you. On studio stuff? Sorry, out of luck..... A friend had built the full-version from the schematic. I think my simplification was better, but was a little more fiddly.... The next question? Does Binaural play into this at all? Or Ambisonic? OH! I remember now. Interaural Crosstalk. Here is article from PS Audio. And yes, to keith.......The article calls is a phase issue. But it is more than that, too..... www.psaudio.com/pauls-posts/interaural-crosstalk/ |
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Post by KeithL on Jul 11, 2022 17:38:04 GMT -5
You're oversimplifying - enormously. The phase of those two drivers is 90 degrees apart, AT THE CROSSOVER FREQUENCY, AND IGNORING MECHANICAL PHASE SHIFTS.(And, yes, a planar driver is going to have less phase shift overall, and likewise for a relatively simple crossover.) The reason that toe-in makes so much difference is that, at 10 kHz, a wavelength of sound is about one inch. And, at 1 kHz, it's about a foot. So, at 1 kHz, a difference in distance between you and the speaker of 2-1/2" inches equates to a 90 degree phase shift. If the speaker is toed in to face you directly then you're closest to the center... and probably an inch or two further from each edge. But, if it's facing straight forward, you will be several more inches closer to the center-ward edge than the outer-ward edge. And, yes, with all that, Magenplanars have FAR less phase shift than most speakers with cones. The idea of "recovering a true left and right" does NOT work in practice with speakers... Because, in practice, sound from both speakers reaches EACH of your ears... And, when you add room reflections, you don't have much control over what actually reaches each ear, and when. Binaural works as well as it does because, by using headphones, you CAN actually control EXACTLY what sound reaches each ear... You cannot even approach that with speakers... Also note that "in real life" the frequency response and the delays of the sound at different frequencies are altered by the way it wraps around your head... And even by the way it wraps around the outside of your ear - and each of us has a different shaped outer ear and inner ear canal. Binaural takes this into account by recording using an actual fake head... to simulate the sound that would actually reach each of your ears. The fancier systems then compensate this information with a "head response transfer function" of your INDIVIDUAL head and ears. (You are actually supposed to have your head measured and get a "custom personal HRTF" to plug into the system.) The result is then "piped directly into your ears" using well isolated headphones. And what you end up with is very close to exactly what you would have heard if you were actually sitting in the recording venue. Ambisonics is a specific method for recording "a surround sound sound field". (And for reproducing it afterwards.) The original "Dynaco Quadapter" included several "extra parts". (You can find the full schematic if you Google it.) The "basic connection" is that: - the (+) terminal from each speaker is connected to the (+) speaker terminal on the amplifier - the (-) terminals on each speaker are connected together and that common junction is then connected to the speaker ground on the amplifier through a 10 Ohm resistor. The Quadapter replaced the 10 Ohm resistor with two 20 Ohm resistors... each going to one of the amplifier's speaker grounds. (If the amplifier has a common ground this is equivalent to a single 10 Ohm resistor... but it protects amplifiers that are NOT common grounded.) In addition there was a 25 Ohm triple power potentiometer... One section was in series with each speaker... And one section was in series with the junction going to the ground resistor... The result was to reduce the overall level while leaving the ratio the same. The net RESULT is as I described... The right channel speaker receives a slightly reduced level of right output minus some left output... The left channel speaker receives a slightly reduced level of left output minus some right output... The fact that the resistor barely got warm simply shows how little AVERAGE power was being sent to the rear speakers. (But that would vary rather widely depending on how much out-of-phase information was present in the audio signal.) The original Quadapter used rather large resistors... And was NOT rated for amplifiers that were very powerful by today's standards... As usual, keith, you don't make things more clear. Sure......time / phase are different ways to express the same thing. Good example? My Maggies have a 6db and 12db crossover......So the 2 drivers are 90 degrees apart. And can be corrected thru toe-in where one of the drivers is a little further from the listener than the other. It is, after all, a 2-way design......And that corrects the problem and helps imaging. These are conventional crossovers, so the 'effect' is not even across the bandpass.... As for SH and SDA. They do the same thing by different means. Yes, Carver went all-electronic and may not have actuallly helped his case. Polk, OTOH, uses wiring between the speakers and a 2nd driver over the frequency range of interest. The effect is not very important at bass frequencies. I don't know how high it extends. But for sure? the DISTANCE between the drivers in each enslosure is key. And is the same (give or take) as the distance between your ears. The idea is that in a stereo recording, Left and Right are generally not 'pure'. Left has some right and the reverse is true. The wiring / driver allows you to subtract one from the other and recover true left or right. Can this sound weird? I'd go listen somewhere to the new generation of SDA speakers. www.crutchfield.com/shopsearch/POLK_SDA_speakers.htmlFrom Crutchfield. good view of the mid / high driver array showing distance. You can refer to, if you can find it, the original Carver advertising for the SH. He makes it pretty easy to understand. forum.polkaudio.com/discussion/186715/sda-2b-crossover-upgrade-do-i-have-this-rightSchematic of SDA system......I hope its right! Keep in mind that the physical distance between the 2 drivers involved is important. As for dynaquad? I just Junked Out the Schematic. I had a 2nd amp I connected the rear effects speakers from PLUS to PLUS (common ground amp) in series. Some experimentation here, since you had a couple choices. I used the VC on this amp as front / rear balance. I also put in a 10ohm / 5 watt power resistor in place of the correct speaker placment. That resistor never got even warm. And the effect was dazzling. On LIVE material, you were in the middle of the audience. And some output came from behind you. On studio stuff? Sorry, out of luck..... A friend had built the full-version from the schematic. I think my simplification was better, but was a little more fiddly.... The next question? Does Binaural play into this at all? Or Ambisonic? OH! I remember now. Interaural Crosstalk. Here is article from PS Audio. And yes, to keith.......The article calls is a phase issue. But it is more than that, too..... www.psaudio.com/pauls-posts/interaural-crosstalk/ |
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Post by leonski on Jul 17, 2022 15:36:04 GMT -5
Couple things than I'll drop it.
Maggies are all you say. But one thing? The toe reduces time delay between 'ways'.......Again with the usual provision for crossover characteristics, of which there is not arguement.
Read up on HOW these panels are used and for the most part mot' facing' the listener or straitght / parallel to the front wall.......I've seen conventional speaekrs with 'time aligned' drivers.
Stepped baffle so mid and tweet are backset from one another and if you draw a vertical line, ALL voice coils are 'lined up' and vertical......Of course, this makes a mess of the baffle. Another time.
If I experimented with Maggies? I'd start with an FIR crossover which has no phase shift thru the passband. Further investigation is warrented and than experiment. I wonder about the
application of SH to a spaeker with this type of crossover?
But the ONE point about the SDA system is the PAIR of drivers. We can talk phase all you want, but to have it make easy sense? I'd talk TIME. And the time that's important is the
time of arrival between the 2 ears. And the idea that if the sound is coming from the left, the right ear will not only perceive the sound later, (directional cue) but have a different frequency
spectrum. Your head will tend to block higher frequencies, related to wavelength to size of obstruction......The mess comes from hearing the same sound from the right speaker, perhaps attenuated,
which wa intended to be left-only. This is where the phase cancelation comes in. You must get rid of the sound from the RH speaker which originated in the left.
That's why the SDA drivers are 6" apart, and have an angle between them....
The Polk system is pretty elegant and simple, but I think the Carver SH has more potential, since if you started TODAY with a clean sheet of paper, you could use DSP techniques.
I'd like to find an old sonic hologram box just long enough for a session of play time.....I don't think it would be easy to DIY this circuit.......and make certain improvements.
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Post by audiobill on Jul 17, 2022 18:36:34 GMT -5
Guys, Maggies have a bass panel and a mid/treble panel. Maggie recommends toe in of 2-3" if the bass panels are outside for phase coherence between bass and treble.
Likewise, if you have the bass panels inside (tweeters outside), placement with virtually no toe-in (speakers parallel to front wall) gets you there, since the bass panel is already closer.
Use a string, laser pointer or measuring tape and draw an arc from the mlp across the speaker faces then have the bass panel 2-3" closer to mlp.
All this from 25 years of Maggie ownership, study, and experimentation.
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Post by leonski on Jul 18, 2022 1:21:12 GMT -5
Audio, I've owned Maggies since at least mid to early 80s. I bought a used pair of MG-1 at an audiophile buddies house. I was blown away and never looked back.
During those days? I had a Kenwood of 60x2 (@8) which had a little more Umph at 4 ohms. I STILL have that amp with me today. Working, but needs some help with
dirty switches.
You generally do NOT want to have the panels parellel to the 'front' wall. You generate an unhealthy backwave,
One thing I learned in all my poking around? Orignal panels like my MG-1 (all revisions) had the pole piece TO the listener. This was changed sometime in the 90s, I think, as my MG1.6s are pole
piece to the wall side.
I have experimented with ALL FOUR logical orientations. Tweeter in or out. And pole piece to or away from listener. Some setups were awful and lasted 30 seconds. Some were good, but upon
further listening were found lacking. A few lasted a week than i went to another setup. I DID take careful measurements, using edges of the panel, the wall and spacing between. My panels are NOT tilted.
I have the spacers in the packng box, but never used them OR the Magnepan labels.
And yes, after all that measuring, I taught myself enough trig to compute the various angles. I ended up with the CL of each panel intersecting a couple feet behind my head. This gave the best image, sounded
best and could be replicated after vacuum or dusting or moving stuff around. It seems to be good for a wider seating of listeners, as during a movie on the big screen...
If I had to start over? You BET I'd use a laser level, a ruler and that blue painters tape. I wish I still had access to Google Sketchup, which would allow a perfectly scaled drawing of my LR, listening setup and relation
to doors and windows.
Your 3.6r use a REAL Ribbon Tweeter, which changes things a little. Not much, but little, since the origin of those frequencies is now much more narrow than on a QR (quasi ribbon) panel which I have measured at 1 3/4" wide.....
I may revisit this some time. I'm not above trying something new, cost-free and fairly easy.....And now that I have a better tool, in that laser level? I may do better.
You must admit, that Magnepan is sort of a DIY dream speaker. Frames? Crossovers? Setup (look into Rooze) and all the rest. The 'choke' tweak? Damping the Pole Piece with some automotive product was a bone of
contention once upon a time. Everybody had a theory / idea. I even heard some hardwood framed (Peter Gunn of Magnestand) MMGs which were really nice. Another friend had some MG1.6 stored, also Gunn modified.
Me? Being on the edge of OCD gives me a look at the extreme. I'd like to try PlyBoo....Bamboo Plywood in 3/4" thickness. And a unique backstay design along with a floor coupling of a new design (roller).
But I don't even own a table saw, which is what I'd need to at least cut the major pieces..... Even some frontwall diffusion would be a nice addition. My far BACKWALL is already damped a very little with a fairly loosely woven
but thick WOOLEN tapestry. I have it about 1 1/2" from the wall, so sound passes thru, bounces and passes thru AGAIN. Instant help when installed a LONG time ago....
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Post by KeithL on Jul 18, 2022 10:46:35 GMT -5
As I mentioned you can still find a Carver C-9 on eBay (for around $125) ... I saw two working ones there last week. (You could probably buy one and sell it again for most of what you paid for it if you didn't like it.) Here's a link to the Owner's Manual (note the VERY specific speaker location advice)... carvermanuals.com/manuals/Pre-Amplifiers/C-9%20Owners.pdfHere's a link to the SERVICE manual... which includes a schematic, a block diagram, a parts list, a foil layout, and all the repair data... (https://thecarversite.com/manuals/mandir/Carver%20C-9%20service%20manual.pdf ) Couple things than I'll drop it. Maggies are all you say. But one thing? The toe reduces time delay between 'ways'.......Again with the usual provision for crossover characteristics, of which there is not arguement. Read up on HOW these panels are used and for the most part mot' facing' the listener or straitght / parallel to the front wall.......I've seen conventional speaekrs with 'time aligned' drivers. Stepped baffle so mid and tweet are backset from one another and if you draw a vertical line, ALL voice coils are 'lined up' and vertical......Of course, this makes a mess of the baffle. Another time. If I experimented with Maggies? I'd start with an FIR crossover which has no phase shift thru the passband. Further investigation is warrented and than experiment. I wonder about the application of SH to a spaeker with this type of crossover? But the ONE point about the SDA system is the PAIR of drivers. We can talk phase all you want, but to have it make easy sense? I'd talk TIME. And the time that's important is the time of arrival between the 2 ears. And the idea that if the sound is coming from the left, the right ear will not only perceive the sound later, (directional cue) but have a different frequency spectrum. Your head will tend to block higher frequencies, related to wavelength to size of obstruction......The mess comes from hearing the same sound from the right speaker, perhaps attenuated, which wa intended to be left-only. This is where the phase cancelation comes in. You must get rid of the sound from the RH speaker which originated in the left. That's why the SDA drivers are 6" apart, and have an angle between them.... The Polk system is pretty elegant and simple, but I think the Carver SH has more potential, since if you started TODAY with a clean sheet of paper, you could use DSP techniques. I'd like to find an old sonic hologram box just long enough for a session of play time.....I don't think it would be easy to DIY this circuit.......and make certain improvements. |
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