Hafler matrix questions. Dynaco / Kenleigh audio QD-2 hardware

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brjoon1021

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Hi,

If this should be posted in another area please feel free to do so. Or post everywhere. I am not getting any help on audiogon's home theatre area. This might be deep waters... don't know.

I have a Dynaco / Kenleigh QD-2 and would like to know if it is worth setting up ? I am at a couple of sticking points which are really annoying me so the overall worth of the journey would be nice to have in view.

Issues that I am having:
1. subwoofer control. I have a passive subwoofer made by the same designer as my fronts center and rear speakers. the designer knew that I would be using a power amp separately for the subwoofer (even suggested the ampl) . Apparently, the subwoofer miay have been designed in error such as the two drivers wired in series / parallel when they should be the other way - as the subwoofer is laughably loud compared to the fronts which the designer also made for my particular use in this system. The QD=2 seems to have no way of attenuating the subwoofer ? Right now the subwoofer is running with the fronts only. Perhaps hafler matrix systems get louder when in 5 -way setup so the sub would sound normal then ? Again, right now it is LOUD. The fronts are 4-ohm. I have no information about the subwoofer impedance or sensitivity. The fronts are rated at 94 ohm but I do not know if specs from the manufacturer are letitimate. ... so the subwoofer integration is problem one. I was told by some folks to buy an attenuator to put inline. I also have a good Onkyo receiver tha I could use as the subwoofer amp and gain a volume control in the deal. Your input on those 2 choices ?

2. If the front speakers are run directly from the amp, bypassing the QD-2, will the center channel have the information that it needs to the do the mojo of ambient or out of phase information manipulation? The mnufacturer seems to put this arrangement as the peon of setups, but I am wondering about this. (Perhaps referring to the Kenleigh audio website www.kenleighaudio.com then "enter here" > "electronics" > "surround sound processors > QD-2 connection / manual might help) It is spartan...

3. my QD-2 is not the original model by Dynaco but apparently a modded version made by kenleigh audio. Please refer to www.kenleighaudio.com then "enter here" > "electronics" > "surround sound processors" You will see that the center and subwoofer outputs been changed on the back panel. I do not think anything else is different from the Dynaco QD-2 except several hundreds of dollars of price were added : ) The manufacturer, Kenleigh audio, told me that there are 3db of separation between the right and left speakers in the design. That might be an upgrade or mod from the original Dynaco ?

3b. The subwoofer and center outputs on this unit are no longer binding posts but RCA. I have no idea why the manufacturer would do this knowing that I have a passive center built by him and a passive subwoofer built by him. Any way to hiook this up ? The rear panel diagram at the website might be helpful.

4. My rears are in a kit form. I have the drivers, the cabinets and a big capacitor. I have no idea where to go from here to get the rears finishes. The original designer has passed away. I am stuck. If anyone knows how I can figure out how to turn the kit into a finished product that would be great. I was told by Kenleigh audio that the rears in a Hafler matrix have a particular sound signature when done right, not flat. If I remember correctly, they are supposed to tilt up in the upper mids then fall sharply in the treble. I could not find documentation for this so far on the website.
- I would be happy to post what drivers I have for the rears and the capacitor value if helpful. I was told by a guy who has a similar system that the capacitor is inline with two of the drivers in parallel, I think. A VERY simple crossover if that is al there is to it.

Thanks
Ray
 
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brjoon1021

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Please tell me they don't really charge $899.00 for two switches a wirewound pot and a handfull of resistors.
Yep. And guess what... my QD2 says Dynaco on the back plate. Really... they bought the old stock which were... way less than $100, changed some of the connections on the back and added many hundreds to the price. Have you seen the speaker prices ? Ridiculous. I did mine as kit. Ripoff company. well, almost surely defunct company at this point.
 
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LB-V

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Well, hello Ray. I'm a bit perplexed with your situation...my apologies. If anybody can help...you are probably in the right place. I am posting a pic of the Kenleighaudio modded QD-2 wiring diagram. It confuses me with the line level / speaker level combinations, but maybe others can reference it for some help.

I hate to say it, but after looking over their website a bit....you may need to cut your losses and get back to the basics. What is your audio goal? What were you hoping to attain musically with the Kenleighaudo equipment?

Screenshot_20221202_192325_Chrome.jpg
 

brjoon1021

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Hi,

I just wanted a good Soundsystem. Kenleigh told me about the systems he set up and away it sputtered and then fizzled leaving hanging.

At this point I only need to figure out : how to connect the passive center channel (given the connection type - RCA coax), how to make the passive sub quieter (attenuator or volume controlled amp) and get the rears assembled with a good crossover. Kenleigh told me that the rears should not have a flat frequency response curve. I don't know if the ideal frequency response curve for hafler matrix for rears can be found anywhere? He said the response should be tilted up in the upper mids and then quickly falling off in the treble region..

Any help with these three things would be coveted.
 

Soundfield

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It seems to me that the Kenleigh modifications to the Dynaco, in attempting to derive some line level signals passively from speaker connections, are fundamentally flawed. Further, the stuff about having to have a specially tailored frequency response for the rear speakers is not remotely worth worrying about. Yes, in theory, the Hafler connection can emphasise high frequency differential noise (but only if its there in the first place) although in practice I never found it a issue and I've used the Hafler connection system with high quality full range speakers for decades! In any case, the fact is that you won't find any speakers with such tailoring!
 

par4ken

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I would bug Kenleigh with your concerns. I feel that you were sold an old idea, the main virtue of which is low cost for an exorbitant sum!

My experience with Quad started in the early seventies with a Quad adaptor purchased from "The Record Club of Canada" for something like $10. The idea being put your best speakers to the front and another set to the rear. The rear speakers do not have to be as good as they are more for ambience. For me it was just a stepping stone to "real" Quad.

At that time a lot of the budget stereo equipment already came with similar Dyna style speaker connections, often given fancy names. IMHO although a good low cost enhancement for regular stereo that may have confused people into thinking that they had a "real" quad system. Yes Midi Dynaquad was conceived a real quad system but very little was ever released in that format.

The use of a "real" decoder offers many advantages. The sound can be more easily tailored to your own preference or to suit the program material. Separate amplifiers for each speaker allow for precise level and balance and equalisation adjustment. You would not have a bass problem if the sub was fed from a separate amplifier.
 

brjoon1021

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It seems to me that the Kenleigh modifications to the Dynaco, in attempting to derive some line level signals passively from speaker connections, are fundamentally flawed. Further, the stuff about having to have a specially tailored frequency response for the rear speakers is not remotely worth worrying about. Yes, in theory, the Hafler connection can emphasise high frequency differential noise (but only if its there in the first place) although in practice I never found it a issue and I've used the Hafler connection system with high quality full range speakers for decades! In any case, the fact is that you won't find any speakers with such tailoring!
Soundfield,
Thanks. Kenleigh's rear speakers had that spectral response. Mine are incomplete and I do not know what the specs should be or how to build a crossover. He thought it mattered quite a bit and it was his thing, but I can't speak to it other than hearsay as I have never heard a system like it ever.
 

Wagonmaster_91

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OK, I'll take a shot at some of this. First, let me say I am sorry that you fell for this scammer. I know that is a bit harsh, but the prices he is charging for such simple electronics should be criminal. It's like an HVAC company charging an old lady $1,000 to change a $1.00 filter on her AC.

1. The subwoofer - In your system you are only dealing with a stereo signal, so yes it only needs the left and right signals. I am sure the signal coming out of the QD-2 is a mono L+R signal. There are two possible reasons the sub would be way louder than the main speakers - One would be that it is more efficient (meaning it takes less power to become louder) than your main speakers. (Speaker efficiency does not correlate directly with speaker quality. Just because a speaker can produce a louder sound with the same power as another doesn't mean one is better than the other. So, don't get hung up on that.) OR - the fact that the sub is getting power from both the left and right channels summed, it is getting twice the power the individual left and right channels are receiving. Either way, the easiest way to correct that problem would be to use a separate amp so you could control the volume on the sub. The Onkyo should be fine for that. As to the wiring, most single speaker subs use a dual wound driver, meaning the single speaker has two voice coils - one for left & one for right. KL may have used a DW woofer or just a regular single coil woofer.
But, a problem is that you are working with speaker level signals coming from your main amp and another amp would need a line level signal. If signal coming out of the QD-2 is speaker level, it may be too "hot" for the Onkyo's input. If your main amp has pre-out and main-in outputs/inputs you could put Y-connectors across those inputs to get a proper signal to send the sub amp that would be controlled by the main amp. (See 3b comment.)

Oh, and that center channel - That is also just a summed L+R signal. There may be a simple crossover added to the QD-2 (I doubt it) or in the center speaker to roll off the highs and lows so that it is a predominately a midrange signal. But really - unless your front speakers are very wide apart - a center speaker in this type of set-up is not needed. It will only detract from the separation of your left & right speakers - and be too loud - so you would need a way to turn it down. But I understand you already have it and want to use it. Maybe use one channel of an input on the Onkyo for the sub and the other for the center, using the balance control on the Onkyo to get levels correct. I would keep that center speaker level low.

2. You can run the front left and right speakers directly, but the QD-2 will still need regular left and right signals to create the rear channels. Remember, you are really only dealing with a stereo source signal, not true surround signals. I'll bet if you opened the QD-2 you would see that the leads going to the front channels is just a straight wire.

3. The 3db of separation - I think you misunderstood what KL said - or maybe he misunderstands: The 3db would be between the front and rear speakers, simply meaning the rears are always just a bit lower in volume than the front.

3b. Possibly the reason for the RCA outputs is that he HAS included a circuit to change the center and sub outputs from speaker level signals to line level. I hope so because that would eliminate the problem I noted about going into the Onkyo amp with too hot of a signal to power the sub. Ask KL if those are line-level signals.

4. I have never heard anyone or any company suggest NOT using a full range speaker speaker (except for a subwoofer, of course) for a front, center, rear or surround channel if possible. In a perfect world, all of your speakers should match in timbre and performance. However, you CAN use lesser quality/capable speakers for surrounds, rears or centers if space, cost or other factors prevent you from using the same speakers. If you have to make sacrifices when it comes to speakers, you always want your front speakers to be the best ones in a system.

Finally, if KL suggest buying something else from him to 'fix' your problems....DON'T!
 

brjoon1021

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I would bug Kenleigh with your concerns. I feel that you were sold an old idea, the main virtue of which is low cost for an exorbitant sum!

My experience with Quad started in the early seventies with a Quad adaptor purchased from "The Record Club of Canada" for something like $10. The idea being put your best speakers to the front and another set to the rear. The rear speakers do not have to be as good as they are more for ambience. For me it was just a stepping stone to "real" Quad.

At that time a lot of the budget stereo equipment already came with similar Dyna style speaker connections, often given fancy names. IMHO although a good low cost enhancement for regular stereo that may have confused people into thinking that they had a "real" quad system. Yes Midi Dynaquad was conceived a real quad system but very little was ever released in that format.

The use of a "real" decoder offers many advantages. The sound can be more easily tailored to your own preference or to suit the program material. Separate amplifiers for each speaker allow for precise level and balance and equalisation adjustment. You would not have a bass problem if the sub was fed from a separate amplifier.
Par4Ken,
Thank you or your response. Kenleigh died. That and his lazy approach to completing projects when had the money up front is why I am in this fix. I don't know much about quad or anything other than typical 2-channel stereo as this was to be my first foray into "better" so I do no know what decoder you are suggesting would be better. I do not really know what quad is exactly as apposed to the hafler matrix. I thought quad was an encoding, a format type. Is it or can it be a decoding from a stereo source like the hafler matrix ? I know Kenleigh added 3 db of separation to the rears, the rear response was contoured so to some degree it was proprietary - he would say advanced. I sent him the review of the Audio Research hafler matrix surround which Richard Vandersteen reportedly uses for his listening. Kenleigh had MUCH to say about what was wrong with the setup, rears, etc... in that system and the review. I only mention that to highlight that this was his thing x10. I have several amps. Amps, unless wubwoofer amps, do not have volume control so separate amplification is part of the problem. To tame the sub I see three ways forward:
1) think I need to take the sub apart and see if the wiring is wrong
2) get an attenuator like the Schiit Sys, or
3) put an integrated amp or Receiver in as the amplification for the subwoofer (I do not know how to do that) so that the amplification for the sub will have volume control. I am using a counterpoint tube amp and preamp to run my fronts. I can use another counterpoint amp to run the sub - but have no voume control of the sub.
OK, I'll take a shot at some of this. First, let me say I am sorry that you fell for this scammer. I know that is a bit harsh, but the prices he is charging for such simple electronics should be criminal. It's like an HVAC company charging an old lady $1,000 to change a $1.00 filter on her AC.

1. The subwoofer - In your system you are only dealing with a stereo signal, so yes it only needs the left and right signals. I am sure the signal coming out of the QD-2 is a mono L+R signal. There are two possible reasons the sub would be way louder than the main speakers - One would be that it is more efficient (meaning it takes less power to become louder) than your main speakers. (Speaker efficiency does not correlate directly with speaker quality. Just because a speaker can produce a louder sound with the same power as another doesn't mean one is better than the other. So, don't get hung up on that.) OR - the fact that the sub is getting power from both the left and right channels summed, it is getting twice the power the individual left and right channels are receiving. Either way, the easiest way to correct that problem would be to use a separate amp so you could control the volume on the sub. The Onkyo should be fine for that. As to the wiring, most single speaker subs use a dual wound driver, meaning the single speaker has two voice coils - one for left & one for right. KL may have used a DW woofer or just a regular single coil woofer.
But, a problem is that you are working with speaker level signals coming from your main amp and another amp would need a line level signal. If signal coming out of the QD-2 is speaker level, it may be too "hot" for the Onkyo's input. If your main amp has pre-out and main-in outputs/inputs you could put Y-connectors across those inputs to get a proper signal to send the sub amp that would be controlled by the main amp. (See 3b comment.)

Oh, and that center channel - That is also just a summed L+R signal. There may be a simple crossover added to the QD-2 (I doubt it) or in the center speaker to roll off the highs and lows so that it is a predominately a midrange signal. But really - unless your front speakers are very wide apart - a center speaker in this type of set-up is not needed. It will only detract from the separation of your left & right speakers - and be too loud - so you would need a way to turn it down. But I understand you already have it and want to use it. Maybe use one channel of an input on the Onkyo for the sub and the other for the center, using the balance control on the Onkyo to get levels correct. I would keep that center speaker level low.

2. You can run the front left and right speakers directly, but the QD-2 will still need regular left and right signals to create the rear channels. Remember, you are really only dealing with a stereo source signal, not true surround signals. I'll bet if you opened the QD-2 you would see that the leads going to the front channels is just a straight wire.

3. The 3db of separation - I think you misunderstood what KL said - or maybe he misunderstands: The 3db would be between the front and rear speakers, simply meaning the rears are always just a bit lower in volume than the front.

3b. Possibly the reason for the RCA outputs is that he HAS included a circuit to change the center and sub outputs from speaker level signals to line level. I hope so because that would eliminate the problem I noted about going into the Onkyo amp with too hot of a signal to power the sub. Ask KL if those are line-level signals.

4. I have never heard anyone or any company suggest NOT using a full range speaker speaker (except for a subwoofer, of course) for a front, center, rear or surround channel if possible. In a perfect world, all of your speakers should match in timbre and performance. However, you CAN use lesser quality/capable speakers for surrounds, rears or centers if space, cost or other factors prevent you from using the same speakers. If you have to make sacrifices when it comes to speakers, you always want your front speakers to be the best ones in a system.

Finally, if KL suggest buying something else from him to 'fix' your problems....DON'T!
Wagonmaster, Gentleman:

Thanks you so much !

Slowly but surely I am getting this figured out. A few questions / clarifications remain:

1. On the Kenleigh Audio website, concerning their QD-2 we have:

Q. "Can I bypass the processor’s front speaker outputs?

A. "Yes you can. Purists will want to wire their system by leaving the amp connected directly to the front speakers. And then running another set of speaker leads from the amp to the processor. Then, simply connect the rear and center speakers only to the processor. Owners of high end systems who want to maintain the integrity of the relationship between the main amp and speakers, should use this approach."

- If I do this where would the QD-2 get its stereo signal which you pointed out as necessary ? Is the answer (that it is saying) that I should have two sets of speaker wires coming from the back of the amp that powers the front speakers ? I have NEVER seen anyone do that before, but I guess if one set has banana and the other set has spades that is feasible or two sets of spades if they are thin enough to squeeze in together. As such, one set going directly to the mains and the other set going to the QD-2's right and left amplifier in speaker wire binding posts ? Do I have this straight ?

2. My understanding of the center is a little murky too I think. The output of the QD-2 labeled "center" is one RCA for coax. I assume then I run an RCA / coax (see I am quick...) to EITHER (?) of the RCA inputs / channels of the stereo amp / receiver / integrated amp that will power the center ? If so, it is not "bad" or hard on that amplifying device to only use one of its channels ?

3. Rear recovery amplification options: This got me thinking.... A fancy receiver that has digital processing internally might be good for the ambient recovery rears as equalization / added ambience / or other effects that might act as a delay if I am not however many miliseconds form the rears that one is supposed to be for the best effect, etc... etc....etc.... For example one of my rears will be crammed in the corner (unavoidable) and the other mid wall. being able to equalize a channel independently to compensate for that (if digital receivers with DSP can do that) might be a Godsend. Or even just being able to put a good equalizer in the path could be great if I want to EQ out that high frequency hash that some have referred to as resulting from the Hafler matrix effect on some recordings. I think this is what Kenleigh mean when he said the rears should not be flat but tilted up in the mids increasingly then sharply falling in the treble. Perhaps this is the signature of reflected / ambient sound by Hafler or kenleigh's reckoning and that this design filters out the treble trash mentioned. above while passing ambience on in the best way ? An EQ could be great for that if there is a decent one available. First I have to get a crossover in the rear speakers. If any of you know a designer that can make a crossover for me that would be a bonus. I have the drivers and the cabinets and two big expensive caps which were meant to be part of or possibly ALL OF a minimalist crossover which Kenleigh was known for.
 

Wagonmaster_91

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MidiMike, that does look like a simple and effective decoder, but judging from Brjoon's comments I'm afraid that building his own decoder from a circuit diagram is probably quite a few steps above his abilities. (Forgive me, Brjoon, if that is incorrect and if it is not it is not meant to be an insult.)

LB-V's question to you, "What is your audio goal? What were you hoping to attain musically with the Kenleighaudo equipment?" is a valid and important question to solving your problems. In this situation your answer, "I just wanted a good Soundsystem" is a bit like telling your doctor, "I hurt. Give some pills to fix that." Of course you want a good sound system, as does everyone on this forum. But there are many different definitions of what that means and for us to help you we have to know what exactly you are trying to achieve.
LB-V wasn't asking about quality. It was about what method(s) of surround sound you are wanting to set up. Legacy quadraphonic such as SQ? QS? CD-4? or modern surround such as 5.1 DTS or Dolby-HD or ambisonics or...? If you just said to yourself, "I don't know what any of that means" that is OK and by exploring the QQ forum, answers to all those questions can be found. Nearly every member here (at least those of us over 40) started with a Hafler type system. I am sorry to tell you most of us did it with nothing more than a single extra speaker behind our listening position and maybe a 10ohm resister inline to that speaker. It sounds to me like you are not trying to get quadraphonic sound, but rather surround sound from stereo recordings. Nothing wrong with that, but they are not the same and there are several types of both. It wouldn't surprise me if Ken was using the term "quad" when actually referring to (synthesized) surround which is what his QD-2 does.

First - I realize Ken died but that website is still up and they are still selling things so someone is there. Call or write to the website and ask if the QD-2 rear, center and sub outputs are line level. It is obvious that the front L&R outputs are speaker level. If the person at the website can't answer that simple question that would tell you all you need to know about their audio/electrical knowledge. Looking at the wiring diagram, I would say they ARE line level since it is telling you to use separate amps for rear, center and sub. I hope so since your sub is passive, you want that to be line level so you can power it with a separate amp with a volume control.

1. Yes. If you are going to run your front speakers directly from your amp, you will need to run additional lines to the QD-2. That needs to come off the amp's front speaker terminals. If you don't feel there is room for two sets of wires, come out of the QD-2 for the front speakers. It is a direct connection, straight wire to those terminals. No reason to make this hard - just hook your fronts to the QD-2.
OR if there are terminals for a second pair of speakers ("B" "Spkrs 2", etc.) on your stereo amp you could use those to send the signals to the QD-2. This method would allow you to turn off the rears, center and sub if you wanted to for some reason. (Of course your amp would have to have the 'two speaker system' option to do this and both A and B speakers systems would need to be on at the same time for all speakers to play.)

2. No, it does no damage to only use one channel on a stereo amp. Besides, as I suggested, use one channel to power the center and the other to power the sub. For example, run one RCA coax cable from the Center output into the Left AUX input of the second amp. Run a second RCA coax cable from the sub to the Right AUX input on the second amp. Now you would have volume (and tone) controls for both the center and sub. You would use the balance control on the second amp to control how much signal is going to each of the two speakers and their input signal would be controlled by your main amp. Any input on the second amp would work except the Phono input.

3. Quit worrying about needing to filter out high frequencies for the rear speakers. As Soundfiled said, it is rarely a problem and only there if the source material has some cross distortion. I have never heard anyone mention that when using a Hafler wired set up. Simply having the rear speakers playing at a lower volume would mask any hash that might exist. That was just part of Ken's BS to think you had to use his box. And you don't use an EQ on individual speakers. I have never seen a home EQ that had speaker level ins or outs.

Look - All the Hafler "system" does is subtract the left channel info from the right channel info (and vice versa) and send that to the rears. Anything that is common to both channels gets canceled out in the rears. The front channels are still getting everything unchanged. For example, say you have a recording and on the left (only) channel is a guitar, on the right (only) is a piano and a singer who's voice is equal volume on both channels so it appears to come from between the front left and right speakers. The rear speakers are only going to have the guitar and the piano - the voice would be canceled out. That's it. Simple. As I said before, in your modified QD-2 both the center and sub outputs are just mono L+R. The original Dynaco QD-2 did not have center or sub out because it didn't need them. Its purpose was to make hooking up the rear speakers easier and give you a volume control for them.

The Subwoofer: Don't take it apart - you don't need to do that. I assume you bought that from KL, too and if it only has one input I can safely say it is a single coil woofer designed to receive a mono L+R signal and has a simple low pass filter attached to it. (Probably a simple choke.) And you do not need to install an amp inside of the sub. Just run a speaker lead from the second amp we are talking about to it.

The Rear speakers: If all that came with the kit is a capacitor then I am also going to declare that the woofer is actually a full range speaker and therefore doesn't need a crossover itself. Maybe it has weak highs so the tweeter makes up for that but you don't want to send low frequencies to a tweeter and a simple capacitor filters those out. Most likely you wire the woofer to cabinet's terminals directly and then run a wire from the woofer's positive terminal to the tweeter's positive. Run a wire from the woofers negative terminal to one of the capacitor's leads/terminal and then a wire from the other lead/terminal to the tweeter's negative terminal. If the capacitor already has leads attached and are long enough you can just use those between the two speakers- no extra wire needed.

Speaker placement: Since both of your rears cannot go in the back corners, can they both go mid-wall? Quit worrying about delay in a Hafler system. There is none. Having both rears in approximately the same location but on opposite sides of the room is ideal to accomplishing what you are trying to do. Both behind you would be best but both beside you would work, but you will need to lower their levels because you still want the front speakers to dominate the sound.

Finally, I urge you to spend a couple of hours on this forum to educate yourself about the differences and types of quad sound. You don't have a solid grasp about what that is exactly and you will save yourself more trouble by gaining that understanding.

Honestly, if it were me, I would sell that QD-2 and get whatever I could out of it. Don't expect to get anywhere near what you paid. You would be better off with a Suround Master made by Involve Audio (no, I don't work for them) and there is lots of info about the SM here on the QQ. But don't buy one of those either before understanding what it is and how you would use it. (Chucky, that's your cue.)

Good luck!
 
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brjoon1021

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Gentlemen,
Thank you very much for your help. I have all that I need to get this setup going as it was intended. Once I am acclimated to it I will decide whether to consider other options including the Involve audio unit.
Thanks Again.
 

LB-V

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Gentlemen,
Thank you very much for your help. I have all that I need to get this setup going as it was intended. Once I am acclimated to it I will decide whether to consider other options including the Involve audio unit.
Thanks Again.

Please keep us posted on progress! This is a geat place to hang around...a ton of knowledge, some humor and a boat load of opinions....
 

brjoon1021

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Just curious, does the bass coming from the rears cancel out base coming from the fronts, at least to some degree, leading to weird base in hafler setups ?
 

par4ken

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Just curious, does the bass coming from the rears cancel out base coming from the fronts, at least to some degree, leading to weird base in hafler setups ?
In my experience no. For one thing considering that bass is often mixed as mono, especially in the LP days much of it cancels out in the rear with the Halfer setup. Hence the possible "need" for a subwoofer?

If a recording had bass in only one channel what you describe might happen due to the reverse phase of one of the rear speakers.

I like to drive my four (identical) speakers with full bass wherever possible and don't use a sub.
 

jaybird100

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Hi,

If this should be posted in another area please feel free to do so. Or post everywhere. I am not getting any help on audiogon's home theatre area. This might be deep waters... don't know.

I have a Dynaco / Kenleigh QD-2 and would like to know if it is worth setting up ? I am at a couple of sticking points which are really annoying me so the overall worth of the journey would be nice to have in view.

Issues that I am having:
1. subwoofer control. I have a passive subwoofer made by the same designer as my fronts center and rear speakers. the designer knew that I would be using a power amp separately for the subwoofer (even suggested the ampl) . Apparently, the subwoofer miay have been designed in error such as the two drivers wired in series / parallel when they should be the other way - as the subwoofer is laughably loud compared to the fronts which the designer also made for my particular use in this system. The QD=2 seems to have no way of attenuating the subwoofer ? Right now the subwoofer is running with the fronts only. Perhaps hafler matrix systems get louder when in 5 -way setup so the sub would sound normal then ? Again, right now it is LOUD. The fronts are 4-ohm. I have no information about the subwoofer impedance or sensitivity. The fronts are rated at 94 ohm but I do not know if specs from the manufacturer are letitimate. ... so the subwoofer integration is problem one. I was told by some folks to buy an attenuator to put inline. I also have a good Onkyo receiver tha I could use as the subwoofer amp and gain a volume control in the deal. Your input on those 2 choices ?

2. If the front speakers are run directly from the amp, bypassing the QD-2, will the center channel have the information that it needs to the do the mojo of ambient or out of phase information manipulation? The mnufacturer seems to put this arrangement as the peon of setups, but I am wondering about this. (Perhaps referring to the Kenleigh audio website www.kenleighaudio.com then "enter here" > "electronics" > "surround sound processors > QD-2 connection / manual might help) It is spartan...

3. my QD-2 is not the original model by Dynaco but apparently a modded version made by kenleigh audio. Please refer to www.kenleighaudio.com then "enter here" > "electronics" > "surround sound processors" You will see that the center and subwoofer outputs been changed on the back panel. I do not think anything else is different from the Dynaco QD-2 except several hundreds of dollars of price were added : ) The manufacturer, Kenleigh audio, told me that there are 3db of separation between the right and left speakers in the design. That might be an upgrade or mod from the original Dynaco ?

3b. The subwoofer and center outputs on this unit are no longer binding posts but RCA. I have no idea why the manufacturer would do this knowing that I have a passive center built by him and a passive subwoofer built by him. Any way to hiook this up ? The rear panel diagram at the website might be helpful.

4. My rears are in a kit form. I have the drivers, the cabinets and a big capacitor. I have no idea where to go from here to get the rears finishes. The original designer has passed away. I am stuck. If anyone knows how I can figure out how to turn the kit into a finished product that would be great. I was told by Kenleigh audio that the rears in a Hafler matrix have a particular sound signature when done right, not flat. If I remember correctly, they are supposed to tilt up in the upper mids then fall sharply in the treble. I could not find documentation for this so far on the website.
- I would be happy to post what drivers I have for the rears and the capacitor value if helpful. I was told by a guy who has a similar system that the capacitor is inline with two of the drivers in parallel, I think. A VERY simple crossover if that is al there is to it.

Thanks
Ray
Brjoon, were you referring to 3dB of separation across the front or rear speakers? I believe a passive system, such as the QD2 uses, should still provide full separation across the front. 3dB is the minimum amount of separation that the human ear can discern. That would be the same as the original Dynaco decoder. When Dynaco originally introduced the system, they marketed it as a way to extract a surround effect from stereo recordings. That it can also use the phase differentials in matrixed quad recordings to deliver a decent, although not accurate, quad effect from SQ and QS recordings, can be a "gateway" to see if you truly like the effect. That's what hooked me on quad, and I've never looked back.
 

Wagonmaster_91

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Just curious, does the bass coming from the rears cancel out base coming from the fronts, at least to some degree, leading to weird base in hafler setups ?
No. The front channels are totally untouched in a Hafler set up. As Par4ken said, bass is usually mixed to both front speakers in a stereo recording (so it appears to come from 'the middle') and so would cancel out in the rears. If the bass was only in one channel, then it would also appear in the rear speaker. This is another reason you want your front speakers to dominate the sound. In this set up you want the soundstage to remain in front of you.

Jaybird, it doesn't sound like Brjoon is trying to play quadraphonic recordings and even stated that he wasn't real clear on what 'quad' means. He is just trying to add some surround elements to his stereo recordings. (And there is nothing wrong with that and should enhance his stereo listening experience.)
 

Soundfield

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I'd go back to basics if I were you Brjoon. I’ve built several ‘Dynaco’ style Hafler boxes for friends. This last one a year ago. A handful of components, cost just a few quid-

hafler box.jpg


It works well, but in truth you actually don’t really need anything even as complex as that. Just a couple of lengths of speaker cable to connect your rear speakers differentially across the front speakers is all that is required to achieve 95% of the functionality of the basic Dynaco box and for next to zero cost. Just remember that the Hafler connection is principally an ambience extractor. In that respect it works remarkably well, particularly with well recorded live stereo material, and is especially well suited to the reproduction of the acoustics of classical music venues (which is why I like it). Whilst I have a main quad system with some sophisticated decoders, my other systems around the house all have Hafler connected speakers. It’s been my default way to set up a system since the 1970’s. I’ve never tried integrating the Hafler system with centre and sub speakers as I’ve never found a need for such things, I just use four decent full range floor standing speakers. I’ve always found that, in HiFi as in so many things, less is more.
 

Sonik Wiz

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I'd go back to basics if I were you Brjoon. I’ve built several ‘Dynaco’ style Hafler boxes for friends. This last one a year ago. A handful of components, cost just a few quid-

View attachment 85955

It works well, but in truth you actually don’t really need anything even as complex as that. Just a couple of lengths of speaker cable to connect your rear speakers differentially across the front speakers is all that is required to achieve 95% of the functionality of the basic Dynaco box and for next to zero cost. Just remember that the Hafler connection is principally an ambience extractor. In that respect it works remarkably well, particularly with well recorded live stereo material, and is especially well suited to the reproduction of the acoustics of classical music venues (which is why I like it). Whilst I have a main quad system with some sophisticated decoders, my other systems around the house all have Hafler connected speakers. It’s been my default way to set up a system since the 1970’s. I’ve never tried integrating the Hafler system with centre and sub speakers as I’ve never found a need for such things, I just use four decent full range floor standing speakers. I’ve always found that, in HiFi as in so many things, less is more.

I like your Dynabox. What is the difference between Spatial & Amb(ience)? What kind of blending does the front panel knob do? Or maybe it's just for level?

One of the best simple designs I've encountered is the original Electro-Voice decoder. A little blend on the front, a lot in the rear (but not total as in Hafler). I think it was successful at giving a listener what they expected when playing stereo "into quad."
 
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