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Post by ashrum on Oct 8, 2023 9:46:34 GMT -5
I am current using definitive bp-2000s for my front stage the manufacturer lists them 300 Watts RMS continuous. I am not sure about peak levels as they do not list that information but i did fin a article a while back testing how each speaker component handled a lot of power in testing as I was Curious about that some time ago. he also seem to think 90 db spl rating was conservative and he tested them closer to 92. I have run them at reference 0db on my preamp connected to a 300 watt amp and have never heard any distortion coming from them. Then again after configuration they are trimmed down 9.5db for the left and 8.0db for the right front channel. My listening level tends to be between -20db to -7db on average for most content as most content would be loud, louder than sitting an atmos movie theater above that volume level. I have considered in the future upgrading my speakers which are about 26 years old now. I know speakers can last a long time, as my father still has a pair of Infinity 2000A electrostatic speakers from the 70's that still sound great. I don't worry so much about the drivers on my bp-2000s more about how long the amps will last for the built in subs. I have considered possibly getting Arendal 1723 Towers down the road.  |
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Post by leonski on Oct 8, 2023 18:53:24 GMT -5
What makes the BP-2000's so special is they are BIPOLE which I think means the front and rear drivers are in phase.......
My panels, OTOH, are DIPOLE which the front /rear waves are OUT of phase.... It should have been possible to design IN
a switch so you could have Bi or Di speakers as you wish. I personally like the immersive effect of such a setup......and experimented
with stacked speakers decades ago in which I faced one set backwards......and experimented with in or out of phase wiring.....
During this time period, I also experimented with a DIY version of what WAS known as 'DynaQuad'......the 'original' 4 channel system
sold as SQ or QS 'matrix' and other similar schemes. Absolutely convincing effects on proper recordings while most studio stuff was
Ho-Hum at best.....
105db output is near the damge level for our ears. How long to induce such problems? OSHA and others say 15 minutes @100db....
This drops by 1/2 for every increase of 3db......
I find it revealing that DT calls for '30 to 300' watts in the OK range. That's a big range and I'd aim somewhere 'in the middle', depending
on other setup issues. Huge room? that sort of thing.....
One LAST issue for me? And this is not really important at all....but DT says one thing for sensitiviity and the reviewer another. FIne and
dandy, Even Stereophile is frequently at odds with the manufacturer. As a matter of fact, and just for example? The KLIPSCH Forte IV
is called 99db sensitive but stereophile measured less....at IIRC, 96db. No Big Deal.
But one thing about sensitivity.? 8 ohms 1 watt is 2.83 volts. That same 2.83 volts is 2 Watts at 4 ohms........Which if you go by voltage,
automatically gives the 4 ohm speaker a 3db higher rating......All other things being equal......
Voltage seems to be the defacto standard, but Watts is where its at!
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Post by ashrum on Oct 8, 2023 21:05:55 GMT -5
Funny you should mention a switch the seemed to have added a switch to their new Dymension series. Though it switches it between forward focused and full bipolar. I think it just turns the rear array off. I definitely would have like your ideas better, being able to switch from bipoles to dipoles.
As for 105db not sure I will ever listen that loud. Accounting for levels after calibration I not sure where having my 8805a preamp puts the output of my amp at around -18db form my front channels but, I would guess that would probably be in the middle. What did find interesting as you seemed to have mentioned listed watts are relative or misleading. I had previously run the speakers on a couple of MA-700 Marantz mono-blocks but I found when hooking them up to a Monolith 7x both rated at 200 watts RMS, that when using the monolith I was running them 10db less on the volume control and they seemed just as loud, same could be said when using XPA HC-1, running lower was more expected as it is a 300 watt RMS amp.
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Post by leonski on Oct 8, 2023 21:15:15 GMT -5
Funny you should mention a switch the seemed to have added a switch to their new Dymension series. Though it switches it between forward focused and full bipolar. I think it just turns the rear array off. I definitely would have like your ideas better, being able to switch from bipoles to dipoles. As for 105db not sure I will ever listen that loud. Accounting for levels after calibration I not sure where having my 8805a preamp puts the output of my amp at around -18db form my front channels but, I would guess that would probably be in the middle. What did find interesting as you seemed to have mentioned listed watts are relative or misleading. I had previously run the speakers on a couple of MA-700 Marantz mono-blocks but I found when hooking them up to a Monolith 7x both rated at 200 watts RMS, that when using the monolith I was running them 10db less on the volume control and they seemed just as loud, same could be said when using XPA HC-1, running lower was more expected as it is a 300 watt RMS amp. The difference in your 'setup' may be written off to the GAIN of the amplifier........ I suspect Higher Gain results in a lower VC setting......and the reverse. for any given REAL loudness level.... In ANY event? All those + - db setups confuse me. Give me good-old-fashioned SPL, any day of the week. Simple switching circuit. I'd have to noodle it out, but I don't think a big issue.....Digging INTO the speaker and identifying the proper wires to switch would be the trick......and I have NO idea of the internal crossover complexity and all that. Maybe if DT would part with a Sketch-O-Matic, that would help? |
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KeithL
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Post by KeithL on Oct 9, 2023 9:27:26 GMT -5
I remember DynaQuad... it tended to work best with live recordings that had "real live ambience"... (I actually had one of the original Dynaco amplifiers that had it built in.) What makes the BP-2000's so special is they are BIPOLE which I think means the front and rear drivers are in phase....... My panels, OTOH, are DIPOLE which the front /rear waves are OUT of phase.... It should have been possible to design IN a switch so you could have Bi or Di speakers as you wish. I personally like the immersive effect of such a setup......and experimented with stacked speakers decades ago in which I faced one set backwards......and experimented with in or out of phase wiring..... During this time period, I also experimented with a DIY version of what WAS known as 'DynaQuad'......the 'original' 4 channel system sold as SQ or QS 'matrix' and other similar schemes. Absolutely convincing effects on proper recordings while most studio stuff was Ho-Hum at best..... 105db output is near the damge level for our ears. How long to induce such problems? OSHA and others say 15 minutes @100db.... This drops by 1/2 for every increase of 3db...... I find it revealing that DT calls for '30 to 300' watts in the OK range. That's a big range and I'd aim somewhere 'in the middle', depending on other setup issues. Huge room? that sort of thing..... One LAST issue for me? And this is not really important at all....but DT says one thing for sensitiviity and the reviewer another. FIne and dandy, Even Stereophile is frequently at odds with the manufacturer. As a matter of fact, and just for example? The KLIPSCH Forte IV is called 99db sensitive but stereophile measured less....at IIRC, 96db. No Big Deal. But one thing about sensitivity.? 8 ohms 1 watt is 2.83 volts. That same 2.83 volts is 2 Watts at 4 ohms........Which if you go by voltage, automatically gives the 4 ohm speaker a 3db higher rating......All other things being equal...... Voltage seems to be the defacto standard, but Watts is where its at! |
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Post by KeithL on Oct 9, 2023 9:54:34 GMT -5
There's a lot of confusion between "Class G" and "Class H"... and different manufacturers use them somewhat interchangeably. The first thing to note is that this refers to the power supply that powers the output stage... The output stage on most Class G and Class H amps, including ours, is a Class A/B output stage... In a normal Class A/B amplifier the output stage runs from a single set of plus and minus power supply rails. In a Class G or Class H amplifier there are two sets of power supply rails for the output stage... The output stage runs from the lower set of power supply rail at lower power levels and draws power from the higher set of rails when it needs to. This improves efficiency slightly in the middle power range - which is what most of us are using most of the time. The difference between "Class G" and "Class H" is between whether the output stage "switches between the two rails" or "slides between them gradually". The higher rail "contributes power" when needed, but the lower rail is never disconnected, so at higher power levels both rails are contributing power. Our amps use what we call "Soft-Switch Class H" which does a gradual transition to the higher rail when it's needed.Over the years different manufacturers have used either term to describe amps with dual power supply rails for the output stage. However, if you actually look at the circuitry, the distinction is not always that clear-cut, and the terminology is somewhat vague. (There are several variations... and one or two older amps actually used more than two sets of rails... ) That 'Class H' stuff is NONSENSE. The amp is conventional A/B........this is a bias condition to the output transistors. That 'G' and 'H' stuff refers to the power supply.....in the case of the amps you are interested in? Apparently the SAME PS which they cal 'class H'...... H would appear to be 'rails' Most of the time you cruise along on maybe 20 volts available to the power transistors. They will be happy nearly forever like this and you will spend MOST of your time there.....up to 30 watts or whatever..... When you demand? Another rail is availble which is at a higher voltage.....60 volts, maybe? And this will provide lots of juice to maximum output. Such a PS may have 2, 3 or perhaps more steps... G on the other hand? Kind of turns up the voltage in time with the Demand. Carver did this a LONG time ago and played with his Tracking power supply and ALWAYS gave his stuff some wacky name or other...... I kind of LIKE this approach....I had one of his early efforts in this regard and it worked fine and overall ran cool..... One thing from the experience bank? You should kind of choose an amp with the speaker in mind. I've seen setups with Kliipsch speakers and Kilowatt Mono amps.....which is vast overkill, when 100 watts would still be a lot. OR? Do I have 'G' and 'H' reversed? I've got very low sensitivity speakers and 'only' 400 watts each......in the form of a 200x2 stereo amp....and linear PS with a largish Toroid and reasonable capacitor bank..... I'd be VERY curious as to the sensitivity of the speakers in ashrum's setup. And how many seperate circuits he has to plug everything INTO..... |
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Post by geebo on Oct 9, 2023 10:51:24 GMT -5
I remember DynaQuad... it tended to work best with live recordings that had "real live ambience"... (I actually had one of the original Dynaco amplifiers that had it built in.) What makes the BP-2000's so special is they are BIPOLE which I think means the front and rear drivers are in phase....... My panels, OTOH, are DIPOLE which the front /rear waves are OUT of phase.... It should have been possible to design IN a switch so you could have Bi or Di speakers as you wish. I personally like the immersive effect of such a setup......and experimented with stacked speakers decades ago in which I faced one set backwards......and experimented with in or out of phase wiring..... During this time period, I also experimented with a DIY version of what WAS known as 'DynaQuad'......the 'original' 4 channel system sold as SQ or QS 'matrix' and other similar schemes. Absolutely convincing effects on proper recordings while most studio stuff was Ho-Hum at best..... 105db output is near the damge level for our ears. How long to induce such problems? OSHA and others say 15 minutes @100db.... This drops by 1/2 for every increase of 3db...... I find it revealing that DT calls for '30 to 300' watts in the OK range. That's a big range and I'd aim somewhere 'in the middle', depending on other setup issues. Huge room? that sort of thing..... One LAST issue for me? And this is not really important at all....but DT says one thing for sensitiviity and the reviewer another. FIne and dandy, Even Stereophile is frequently at odds with the manufacturer. As a matter of fact, and just for example? The KLIPSCH Forte IV is called 99db sensitive but stereophile measured less....at IIRC, 96db. No Big Deal. But one thing about sensitivity.? 8 ohms 1 watt is 2.83 volts. That same 2.83 volts is 2 Watts at 4 ohms........Which if you go by voltage, automatically gives the 4 ohm speaker a 3db higher rating......All other things being equal...... Voltage seems to be the defacto standard, but Watts is where its at! I had one of these quite a long time ago and it worked quite well in its day.    |
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Post by leonski on Oct 9, 2023 15:45:08 GMT -5
First? Keith pretty much restated what I had already written.......G / H , however are REVERSED in Japan from what we consider either rails or variable output voltage.
Transistor bias CAN be factored into this, which gives maybe a 'High Bias' design which gradually turns into a conventionally biased amp as power rises. A neat solution since
most ot the time you really use a LOT less power than you may think.
As for DYNA Quad?
My verison was VERY different but had some of the same features.
First? I used 2 stereo amps, being careful to use a conventional, common ground type.
So as it turned out? Wire the front channels TO the stereo amp JUST LIKE NORMAL......You now have 'just' a regular stereo'.....
Do all the normal stuff with relative phase and locating the speakers for 'best' result.
THAN? Using a SECOND AMP? Wire a similar (I had JBL4311 front and RSL3600 on the rear.......set of speakers from POSITIVE to POSITIVE'
simply ignorming the grounds, which are BOTH tied to the chassis......
Now your signal is based on the DIFFERENCE between the standard pair of channels.....And can vary from LEFT being high to RIGHT being higher in voltage.
The DIFFERENCE is what amounts to a '3rd channel'......Forget all those resistors and switches and that triple vol control.......I'd vary my front / rear level using
the VC on the REAR amp......And usually left it alone....
I would experiment with rear speaker wiring. From amp+ to speaker +or- than to the OTHER speakers +or-.......Than back to the other + on the amp......
If you are the least bit weird about this.......and I was at first......I wired a 10 ohm, 10 watt POWER RESITOR to the normal speaker position on the 'rear' amplifier....
STUDIO recordings hadn't the out of phase information which made this work and work WELL.
But LIVE recordings? You were in the MIDDLE of the audience. Spooky good sound.
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Post by KeithL on Oct 9, 2023 16:56:43 GMT -5
There are a lot of different options for how to arrange an output stage. Class G and Class H do not specifically relate to the amount of bias on the output stage. You could use multiple rails with any sort of amp - Class A, Class A/B, or even Class B. However most modern amplifiers, including ours, are going to use a Class A/B output stage. In a solid state amplifier the operating class refers to the amount of bias. In a Class B solid state amplifier, there is no "idle bias", and each output transistor only conducts for half of the cycle. (This tends to cause distortion around the transition point which can be difficult to avoid.) And, in a Class A solid state amplifier, the idle current is greater or equal to the maximum current conducted by either transistor. (This tends to result in a LOT of heat. A Class A amplifier is AT BEST 25% efficient... and burns full power at zero output.) In a Class A/B solid state amplifier, there is ALWAYS some bias current flowing in BOTH out transistors, but only a relatively small amount. This is why it is technically true that ANY Class A/B amplifier "runs in Class A at very low power". And you can increase the bias to create "a high-bias Class A/B amplifier that runs in Class A for more of its operating range". (This is different than in a Class A/B tube amplifier - where each output tube actually doesn't conduct for part of each cycle.) And, yes, various companies, including notably Krell, have used various methods to vary the bias dynamically based on signal level. While there are arguably benefits to having a higher bias at higher output levels... The down-side is that, by varying the bias on the output devices, you are shifting their operating point, which can cause linearity issues. Another interesting concept is a cascode output stage... where a second set of output devices "holds the main output devices at a fixed operating point". However, in practice, cascode circuits are far more complex, less efficient, and the actual practical benefits seem to be rather limited. The real bottom line is that most of these output stages can deliver excellent performance if implemented well. (And Class A/B + Class H delivers an excellent combination of efficiency and sound quality.) Incidentally... Dynaquad actually creates a combination of "direct sound" and "difference sound" in the rear channels. With Dynaquad the "ground terminals" of the rear channels are tied together and the common point is then grounded through a resistor. This creates something that is more or less L = +2/3L-1/3R and R = +2/3R-1/3L . That puts a little bit more of the front channels in the rear than simply tying the two rear ground terminals together and floating the junction. The Dynaquad connection looks like a "T" and the Volume control just puts an equal big-ass power rheostat in each of the three "legs" to lower the level with the same "mix". (If you're going to use separate amplifiers you can do the same math at line level with a handful of op-amps and a few resistors.) (And, if you do that, you can rather easily add a variable crossfeed control too...) First? Keith pretty much restated what I had already written.......G / H , however are REVERSED in Japan from what we consider either rails or variable output voltage. Transistor bias CAN be factored into this, which gives maybe a 'High Bias' design which gradually turns into a conventionally biased amp as power rises. A neat solution since most ot the time you really use a LOT less power than you may think. As for DYNA Quad? My verison was VERY different but had some of the same features. First? I used 2 stereo amps, being careful to use a conventional, common ground type. So as it turned out? Wire the front channels TO the stereo amp JUST LIKE NORMAL......You now have 'just' a regular stereo'..... Do all the normal stuff with relative phase and locating the speakers for 'best' result. THAN? Using a SECOND AMP? Wire a similar (I had JBL4311 front and RSL3600 on the rear.......set of speakers from POSITIVE to POSITIVE' simply ignorming the grounds, which are BOTH tied to the chassis...... Now your signal is based on the DIFFERENCE between the standard pair of channels.....And can vary from LEFT being high to RIGHT being higher in voltage. The DIFFERENCE is what amounts to a '3rd channel'......Forget all those resistors and switches and that triple vol control.......I'd vary my front / rear level using the VC on the REAR amp......And usually left it alone.... I would experiment with rear speaker wiring. From amp+ to speaker +or- than to the OTHER speakers +or-.......Than back to the other + on the amp...... If you are the least bit weird about this.......and I was at first......I wired a 10 ohm, 10 watt POWER RESITOR to the normal speaker position on the 'rear' amplifier.... STUDIO recordings hadn't the out of phase information which made this work and work WELL. But LIVE recordings? You were in the MIDDLE of the audience. Spooky good sound. |
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Post by KeithL on Oct 9, 2023 16:58:04 GMT -5
As I recall what I had was the SCA-80Q - which was an integrated amp with the Quadapter built in... It actually worked pretty well... I remember DynaQuad... it tended to work best with live recordings that had "real live ambience"... (I actually had one of the original Dynaco amplifiers that had it built in.) I had one of these quite a long time ago and it worked quite well in its day. |
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Post by leonski on Oct 9, 2023 18:38:58 GMT -5
I'm not certain an integrated OPAMP was available to me when I did my experiments. I went the 'easy' way after just looking how the darn thing was wired and I may also have had access to a schematic....but its been YEARS....decades, actually.....
Front rear speaker matching was sort of important. My RSL and the JBL were such a match. The RSL was a SoCal 'boutique' brand which even made some inroads into recording studios......The speakers I used were ALL 12" 3-way with level controls.....
Indeed, the RSL were modeled after the JBL and were a wonderful value......I sold 'em when I bought my Magnepans.....somewhere around 40 years ago.....
At that time, I was an apartment dweller and I heard an all ADVENT original system......on some kind of QS or SQ 4-channel receiver. FINE....
All my experiments were done well before my Magnepan days.....
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Post by KeithL on Oct 10, 2023 13:08:18 GMT -5
The schematic of the Quadapter is readily available if you Google for it (but it is drawn in a way that makes it look more complicated). Basically, simplified for specifically a common ground amplifier, and removing the level control and the balance test switch... - the front two speakers are connected as normal - the (+) terminals on the rear speakers are connected as normal - but the (-) terminals on the rear speakers are connected together... then that junction is connected to ground through a 10 Ohm resistor. - that's all there is to it (They actually "split" that resistor into 2 x 20 Ohm resistors, one going to each ground, which is equivalent to a single 10 Ohm resistor on a common ground system.)  I remember Advents... I had a pair... in real walnut veneer... they were quite nice for their day. Awesome bass... nice treble... but a little bit rounded off... and OK but not great midrange... I'm not certain an integrated OPAMP was available to me when I did my experiments. I went the 'easy' way after just looking how the darn thing was wired and I may also have had access to a schematic....but its been YEARS....decades, actually..... Front rear speaker matching was sort of important. My RSL and the JBL were such a match. The RSL was a SoCal 'boutique' brand which even made some inroads into recording studios......The speakers I used were ALL 12" 3-way with level controls..... Indeed, the RSL were modeled after the JBL and were a wonderful value......I sold 'em when I bought my Magnepans.....somewhere around 40 years ago..... At that time, I was an apartment dweller and I heard an all ADVENT original system......on some kind of QS or SQ 4-channel receiver. FINE.... All my experiments were done well before my Magnepan days..... |
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Post by leonski on Oct 10, 2023 13:38:02 GMT -5
For ME? I couldn't source the switches and that (10 watt?) triple rheostat?
So I did the 'double amp' version and used teh back amps level control (Kenwood KA7100)
as F/R 'balance'......
Needed ONLY a stereo single ended cable from front pre to back integrated......And at line level,
that made the balance easy and intuitive.
Advents were considered a real value. Especially if you bought the 'utility' cabinet version......
I wish I remembered pricing, but Bang For Buck was tough to beat.......And the advert about
needing to spend EPIC amount os money to buy 'better' was telling.....
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Post by KeithL on Oct 10, 2023 16:19:12 GMT -5
The rheostat and the switch were probably both custom-to-order parts. But, if you had four similar speakers, they also wouldn't really be necessary.  For ME? I couldn't source the switches and that (10 watt?) triple rheostat? So I did the 'double amp' version and used teh back amps level control (Kenwood KA7100) as F/R 'balance'...... Needed ONLY a stereo single ended cable from front pre to back integrated......And at line level, that made the balance easy and intuitive. Advents were considered a real value. Especially if you bought the 'utility' cabinet version...... I wish I remembered pricing, but Bang For Buck was tough to beat.......And the advert about needing to spend EPIC amount os money to buy 'better' was telling..... |
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Post by leonski on Oct 10, 2023 18:58:35 GMT -5
Almost makes me want to find a small stereo integrated and a pair of reaonably sensitive speakers....and run an experiment here in my LR.......
ALMOST! What made me drop the whole thing was when I saw a DISCRETE 4 channel TT with a special cart that would respond to the necessary 40khz or so......
LIke that would have lasted past half a dozen playings......
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Post by KeithL on Oct 11, 2023 13:02:02 GMT -5
That system was called CD-4. CD-4 albums usually lasted for more than a half dozen playings... but never more than 100 or so... There were also other... issues. The system itself stored what amounted to two channels of FM-stereo audio on vinyl (each "channel" had a channel of audio and its own "stereo subcarrier")... So, while they could get ticks and pops like normal vinyl, you could also get things like drops in channel separation... They also required a special cartridge (with a Shibata stylus)... That stylus also wore out somewhat quickly since it had to track at 2-3 grams... (And remember that, unless you had two turntables, or constantly changed cartridges, you were using that cartridge to play ALL of your albums.) The CD-4 decoder was also rather complicated... and separate decoders were quite expensive... There was also the annoying fact that, while there were few 4-channel albums to begin with, most were in either CD-4 or SQ-4 (and SQ-4 was more popular). So, unless you had both, even if your favorite album was available in "4 channel", it often wasn't in the right kind of 4 channel. (I had a Technics 4-channel receiver that supported SQ-4 but I never even considered getting the special cartridge and all the rest of the kit for CD-4.) It's also worth noting that, as you might expect, there were several minor variations in the SQ-4 standard - like Sansui's "QS" decoder. And, later on, there were also additional options for SQ-4, like "SQ-4 full logic decoders", which did post processing to improve channel separation... (Note that SQ-4 four-channel is an analog matrix system... and works solely by adding and subtracting analog signals after doing frequency selective phase shift.) Anyone who likes the idea of "generic analog surround sound decoding" should check out the Schiit Audio Syn. It looks... interesting (I've never heard it). Almost makes me want to find a small stereo integrated and a pair of reaonably sensitive speakers....and run an experiment here in my LR....... ALMOST! What made me drop the whole thing was when I saw a DISCRETE 4 channel TT with a special cart that would respond to the necessary 40khz or so...... LIke that would have lasted past half a dozen playings...... |
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Post by KeithL on Oct 11, 2023 13:06:58 GMT -5
For anyone who is actually interested... There are currently TWO Dynaco Quadapters listed on eBay... One is listed for $37.95 The other is listed at $50 OBO (and they spelled Dynaco wrong)  For ME? I couldn't source the switches and that (10 watt?) triple rheostat? So I did the 'double amp' version and used teh back amps level control (Kenwood KA7100) as F/R 'balance'...... Needed ONLY a stereo single ended cable from front pre to back integrated......And at line level, that made the balance easy and intuitive. Advents were considered a real value. Especially if you bought the 'utility' cabinet version...... I wish I remembered pricing, but Bang For Buck was tough to beat.......And the advert about needing to spend EPIC amount os money to buy 'better' was telling..... |
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Post by leonski on Oct 11, 2023 13:09:13 GMT -5
I'll take 'em BOTH and go 8 channel!
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