Turning normal speakers into SDA’s
Comments
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Maybe but adding a one ohm resistor at each speaker input will buy you some insurance. Yes you will lose a little power but a resistor won't effect the sound. And you can always turn your amp up a few decibels to compensate.
And you are going to use a cheap spare amplifier.....aren't you? Most cheap receivers don't like 3 ohm loads. Start off being cautious.
I didn't get much listening time in yet but I did notice a difference from where I placed the "SDA" speakers. I started with them positioned on the inside of the main speakers but thought I heard a difference when they were place outside. I want to put them further out but for now I don't have an interconnect wire long enough.
And let us know your opinions when listening,
I was going to use my Technics SU-v75. Its not a super cheap receiver, but it has devalued a lot. I still don’t trust it though, I’m gonna add some resistors, but I imagine it can’t hurt for a brief test, cause I don’t know when we’ll make it to HobbyTown, -
Here (again FWIW, I am obsessing again...) is the Ur-review of the Ur-SDA loudspeaker, from High Fidelity January 1983.
https://www.americanradiohistory.com/Archive-High-Fidelity/80s/High-Fidelity-1983-01.pdf
Starts on page 41
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mlistens03 wrote: »What is up with the top and bottom drivers on the left side in that pic Doc? They seem different from the rest of them all... is that normal?
They are mass plugs for tuning the Fs(?) Of those drivers. -
mlistens03 wrote: »
I was going to use my Technics SU-v75. Its not a super cheap receiver, but it has devalued a lot. I still don’t trust it though, I’m gonna add some resistors, but I imagine it can’t hurt for a brief test, cause I don’t know when we’ll make it to HobbyTown,
I understand..........But just so you know my brief test stated getting louder and louder!
Do you have speaker stands that puts the SDA drivers at close to the same level as your main speaker drivers? I didn't experiment yet but I am pretty sure you need it that way. Putting something on the floor probably won't work.
There is a good chance your setup will sound even better than my garage sale / spare parts rig. -
I understand..........But just so you know my brief test stated getting louder and louder!
Do you have speaker stands that puts the SDA drivers at close to the same level as your main speaker drivers? I didn't experiment yet but I am pretty sure you need it that way. Putting something on the floor probably won't work.
There is a good chance your setup will sound even better than my garage sale / spare parts rig.
I’ll most likely use my Mission speakers as stands, as the top of their cabinet almost perfectly reaches the top of the wood veneer on my LSi’s.
I’m getting excited for this!! If the results are as good as you are saying yours were, it may never be taken apart again...
Also, a quick question. Could I use a Y-connector on the RCA pre-outs on my Yamaha, and then run that to my power amplifier and the receiver for the SDA effect? Then I wouldn’t have to worry about converting the signal to line level, etc. -
Probably, but you might want to read this before you do, whether you end up goin' for it or not
https://www.rane.com/note109.html
OK for splitting signals per Rane, kinda less than ideal for mixing outputs (e.g, the time honored sum to mono).
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mhardy6647 wrote: »Probably, but you might want to read this before you do, whether you end up goin' for it or not
https://www.rane.com/note109.html
OK for splitting signals per Rane, kinda less than ideal for mixing outputs (e.g, the time honored sum to mono).
Thanks for sharing that!
It seems like the way that I would do it is supposedly OK. splitting each main preout signal into two. I have a few of these kicking around, so I’ll try and give that a go tomorrow as well.
Thanks again, to everyone! -
mlistens03 wrote: »Also, a quick question. Could I use a Y-connector on the RCA pre-outs on my Yamaha, and then run that to my power amplifier and the receiver for the SDA effect? Then I wouldn’t have to worry about converting the signal to line level, etc.
I don't immediately see anything wrong with it but I don't know. If that works it would be a big advantage to the way I have my system set up. I have dual outs on my CD player. These are fed into two totally different integrated amplifiers / speakers combos. The volume of the main speakers and the SDA speakers is totally independent. I can listen to one or the other (or both) but I have to turn a knob for each. This works for experimenting (and it is cool to listen to just the SDA speakers).
In your case (if it works) you could set the amount of SDA effect with the SDA integrated amp and it should track the volume changes from your preamp.
The system I described is different from the signal to line level setup Ken described. I do not get the signal for the SDA side from the main amp's speaker output. I get both signals direct from the CD player. -
...............but then, he's MATT POLK, he knows a thing or two about speaker design.
H9
IIRC at one of the factory Polkfests we attended, Matt said he came up with the SDA idea when he nearly drowned. So every time Polk needed an idea, they tried to drown Matt.
j/k about the latter but the prior is true.
Salk SoundScape 8's * Audio Research Reference 3 * Bottlehead Eros Phono * Park's Audio Budgie SUT * Krell KSA-250 * Harmonic Technology Pro 9+ * Signature Series Sonore Music Server w/Deux PS * Roon * Gustard R26 DAC / Singxer SU-6 DDC * Heavy Plinth Lenco L75 Idler Drive * AA MG-1 Linear Air Bearing Arm * AT33PTG/II & Denon 103R * Richard Gray 600S * NHT B-12d subs * GIK Acoustic Treatments * Sennheiser HD650 * -
How many of y’all have had your crossovers modded by sid the kid? Let the kid experiment. Maybe he’ll rock the audio world!Living Room 2.2: Usher BE-718 "tiny dancers"; Dual DIY Dayton audio RSS210HF-4 Subs with Dayton SPA-250 amps; Arcam SA30; Musical Fidelity A308; Sony UBP-x1000es
Game Room 5.1.4: Denon AVR-X4200w; Sony UBP-x700; Definitive Technology Power Monitor 900 mains, CLR-3000 center, StudioMonitor 350 surrounds, ProMonitor 800 atmos x4; Sub - Monoprice Monolith 15in THX Ultra
Bedroom 2.1 Harmon Kardon HK3490; Bluesounds Node N130; Polk RT25i; ACI Titan Subwoofer -
^^^ Agreed
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Sorry, I wasn’t clear, what I mean is, can I use 2 Y-connector’s to split the left channel into two and split the right channel into two, and then use those two channels for the two amps?
Thanks!Post edited by [Deleted User] on -
Not sure if anyone's interested, but here's what the Hafler (Dynaco) QD-1 Quadaptor looks like.
Dynaco QD-1 front by Mark Hardy, on Flickr
Dynaco QD-1 rear by Mark Hardy, on Flickr -
It would be relatively easy to create a "Rube Goldberg" SDA. An example would be a pair of RTA15tls (or similar), and a pair of Monitor 4s. Place the Monitor 4s on stands, on the outside of each RTA15. Disconnect the tweeters on the 4s, then connect and invert the signal from the opposite channel. You could even put a 2nd order high pass filter inline, at around 150 Hz to mitigate bass cancellation. A poor mans 3.1tl.Home Theater/2 Channel:
Front: SDA-2ATL forum.polkaudio.com/discussion/143984/my-2as-finally-finished-almost/p1
Center: Custom Built forum.polkaudio.com/discussion/150760/my-center-channel-project/p1
Surrounds & Rears: Custom Built forum.polkaudio.com/discussion/151647/my-surround-project/p1
Sonicaps, Mills, RDO-194s-198s, Dynamat, Hurricane Nuts, Blackhole5
Pioneer Elite VSX-72TXV, Carver PM-600, SVS PB2-Plus Subwoofer
dhsspeakerservice.com/ -
2 sets of 5jr's with outer tweets disconnected and inner MWs swapped to 6510s sound great as well with CRS+ crossovers.
When I first started experimenting I was curious what the sub bass drive inductor would do when the MWs were in separate enclosures.
Don't take experimental gene therapies from known eugenicists. -
Thanks for telling me!
Could I do what I was talking about, and then connect the bookshelf speakers to the positive and positive terminals on the amp? Would that create the difference signal?
Sorry if I’m being difficult.
I did pick up resistors, although HobbyTown didn’t have any 1 ohm resistors that weren’t ceramic, and I don’t know where I could put a very hot resistor. I’m gonna dig around in a broken amplifier that I have here, and see what I can find.
Thanks again!
MicahPost edited by [Deleted User] on -
I'm late to the thread, but I say go for it. It's much easier to do with two separate amps, but much harder to synchronize the volume that way. I've thought of @westmassguy 's example before as an experiment, and even compared the crossovers, although I was mostly looking at the difference in the high pass since people find issue with the tweeter crossover on the RTA15. In theory though you could use a 3.1TL crossover with an RTA15 + M4 combo, but the bass might not be in perfect sync.
Here's an @mhardy6647 project. Use two identical full range speakers. Split the source. Run one source directly to the inner stereo pair. Run the other source through an equalizer lowered to roughly half volume, and then to the amp wired out of phase. Play with the equalizer to see what cancellation frequency range and volume has the best affect. Play with the spacing and see how the sound stage changes. A side project of this would be to see how different recording styles change the affect.
Going slightly off topic and relating to the stereo difference signal thread, there are are a variety of recording techniques and microphone types that are supposed to accurately reproduce the sound stage in scale and make use of the the cross talk and natural cancellations. Essentially the microphones are picking up the cross talk and cancellations, and when the speakers are set up just right, the reproduction will be very accurate because they are reproducing the cross talk and cancellations in perfect timing when they reach our ears.
Further off topic, the 3.1TL has always been a mystery to me. As I understand it for the rest of the range, the dimensional speakers are about 1/2 output of the stereo speakers, either in volume or number of speakers. Based on this, the dimensional speaker on the 3.1 would in theory need to be twice the volume of a single stereo speaker, and likely over driven, so I must be missing something. -
Thanks!I'm late to the thread, but I say go for it. It's much easier to do with two separate amps, but much harder to synchronize the volume that way. I've thought of @westmassguy 's example before as an experiment, and even compared the crossovers, although I was mostly looking at the difference in the high pass since people find issue with the tweeter crossover on the RTA15. In theory though you could use a 3.1TL crossover with an RTA15 + M4 combo, but the bass might not be in perfect sync.
Here's an @mhardy6647 project. Use two identical full range speakers. Split the source. Run one source directly to the inner stereo pair. Run the other source through an equalizer lowered to roughly half volume, and then to the amp wired out of phase. Play with the equalizer to see what cancellation frequency range and volume has the best affect. Play with the spacing and see how the sound stage changes. A side project of this would be to see how different recording styles change the affect.
Going slightly off topic and relating to the stereo difference signal thread, there are are a variety of recording techniques and microphone types that are supposed to accurately reproduce the sound stage in scale and make use of the the cross talk and natural cancellations. Essentially the microphones are picking up the cross talk and cancellations, and when the speakers are set up just right, the reproduction will be very accurate because they are reproducing the cross talk and cancellations in perfect timing when they reach our ears.
Further off topic, the 3.1TL has always been a mystery to me. As I understand it for the rest of the range, the dimensional speakers are about 1/2 output of the stereo speakers, either in volume or number of speakers. Based on this, the dimensional speaker on the 3.1 would in theory need to be twice the volume of a single stereo speaker, and likely over driven, so I must be missing something.Post edited by [Deleted User] on -
Just try and use what you have laying around. No need to invest in crossovers or anything like that. Just for shites and giggles, use any two pair. Only concern, is the load on the receiver/integrated. Two pairs of 8 ohm speakers in parallel is 4 ohms or less.Home Theater/2 Channel:
Front: SDA-2ATL forum.polkaudio.com/discussion/143984/my-2as-finally-finished-almost/p1
Center: Custom Built forum.polkaudio.com/discussion/150760/my-center-channel-project/p1
Surrounds & Rears: Custom Built forum.polkaudio.com/discussion/151647/my-surround-project/p1
Sonicaps, Mills, RDO-194s-198s, Dynamat, Hurricane Nuts, Blackhole5
Pioneer Elite VSX-72TXV, Carver PM-600, SVS PB2-Plus Subwoofer
dhsspeakerservice.com/ -
That’s something I’m worried about. My speakers for the SDA effect (Boston Acoustics CR-75’s) don’t have any info online about their impedance, other than 8 ohms nominal. I don’t know how to measure the impedance, so my plan is to play it safe and run them on the Crown, which has protection built in, and then use the Technics and the Missions for the mains, because I know that they can run on the Technics just fine.
I wanted to get some 1 or 2 ohm resistors to wire in series with the speakers, and I still will most likely, but all they had at HobbyTown was ceramic resistors in those resistances, and I don’t know how that’ll work out with how much heat they produce.
Thanks again! -
mlistens03 wrote: »That’s something I’m worried about. My speakers for the SDA effect (Boston Acoustics CR-75’s) don’t have any info online about their impedance, other than 8 ohms nominal. I don’t know how to measure the impedance, so my plan is to play it safe and run them on the Crown, which has protection built in, and then use the Technics and the Missions for the mains, because I know that they can run on the Technics just fine.
I wanted to get some 1 or 2 ohm resistors to wire in series with the speakers, and I still will most likely, but all they had at HobbyTown was ceramic resistors in those resistances, and I don’t know how that’ll work out with how much heat they produce.
Thanks again!
Home Theater/2 Channel:
Front: SDA-2ATL forum.polkaudio.com/discussion/143984/my-2as-finally-finished-almost/p1
Center: Custom Built forum.polkaudio.com/discussion/150760/my-center-channel-project/p1
Surrounds & Rears: Custom Built forum.polkaudio.com/discussion/151647/my-surround-project/p1
Sonicaps, Mills, RDO-194s-198s, Dynamat, Hurricane Nuts, Blackhole5
Pioneer Elite VSX-72TXV, Carver PM-600, SVS PB2-Plus Subwoofer
dhsspeakerservice.com/ -
westmassguy wrote: »You can get 100 watt L-Pads for not a lot of coin too, instead of the resistors.
This is a very good idea!
As to measuring impedance, it's actually not all that hard to do, at least for a driver sans crossover. I do not know how accurate the results would be when applied to a multi-"way" loudspeaker with an onboard crossover, though. I've never really thought about it.
http://sound.whsites.net/tsp.htm
Heck, today one can use a phone instead of a generator to get the needed signals!
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I'm late to the thread, but I say go for it. It's much easier to do with two separate amps, but much harder to synchronize the volume that way. I've thought of @westmassguy 's example before as an experiment, and even compared the crossovers, although I was mostly looking at the difference in the high pass since people find issue with the tweeter crossover on the RTA15. In theory though you could use a 3.1TL crossover with an RTA15 + M4 combo, but the bass might not be in perfect sync.
Here's an @mhardy6647 project. Use two identical full range speakers. Split the source. Run one source directly to the inner stereo pair. Run the other source through an equalizer lowered to roughly half volume, and then to the amp wired out of phase. Play with the equalizer to see what cancellation frequency range and volume has the best affect. Play with the spacing and see how the sound stage changes. A side project of this would be to see how different recording styles change the affect.
Going slightly off topic and relating to the stereo difference signal thread, there are are a variety of recording techniques and microphone types that are supposed to accurately reproduce the sound stage in scale and make use of the the cross talk and natural cancellations. Essentially the microphones are picking up the cross talk and cancellations, and when the speakers are set up just right, the reproduction will be very accurate because they are reproducing the cross talk and cancellations in perfect timing when they reach our ears.
Further off topic, the 3.1TL has always been a mystery to me. As I understand it for the rest of the range, the dimensional speakers are about 1/2 output of the stereo speakers, either in volume or number of speakers. Based on this, the dimensional speaker on the 3.1 would in theory need to be twice the volume of a single stereo speaker, and likely over driven, so I must be missing something.
Heh... this will be added to the long list of gotta get a round tuit projects. -
mhardy6647 wrote: »
This is a very good idea!
As to measuring impedance, it's actually not all that hard to do, at least for a driver sans crossover. I do not know how accurate the results would be when applied to a multi-"way" loudspeaker with an onboard crossover, though. I've never really thought about it.
http://sound.whsites.net/tsp.htm
Heck, today one can use a phone instead of a generator to get the needed signals!
Thanks! -
You may want to look into some digital crosstalk cancellation options. As my screen name suggests, I have used ambiophonics in a small setup which gives similar results to SDA speakers but without the extra drivers and with more options for adjusting parameters. I use the miniambio box which appears to no longer be available but you can purchase a similar item called MiniDSP 2x4 which can run an ambiophonics crosstalk cancellation plugin.2 Channel - Polk SDA-2BTL, Carver TFM-35, Peachtree iDAC, Qobuz streamed via Episode Lynk using bubble UPnP server
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FWIW, besides the popular MiniDSP product(s), good ol' PartsExpress just introduced a similar product that is meant to be easier to use out of the box than the MiniDSP gizmos. No hands-on experience, YMMV, etc., etc. -- but seemed worthy of mentioning in the context of this thread, even before the post above.
https://www.parts-express.com/dayton-audio-dsp-408-4x8-dsp-digital-signal-processor-for-home-and-car-audio--230-500 -
Apropos of nothing: Happened to be perusing an old, old issue of High Fidelity (courtesy of www.americanradiohistory.com) looking for Something Else Entirely... and happened upon this Rodrigues cartoon. It seemed strangly apt for this thread, so I figured I'd share it here.
source https://www.americanradiohistory.com/Archive-HiFI-Stereo/60s/HiFi-Stereo-Review-1967-12.pdf
The late Charles Rodrigues was the hifi cartoonist (as well as a contributor to Playboy, National Lampoon, and others).
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mlistens03 wrote: »I wanted to get some 1 or 2 ohm resistors to wire in series with the speakers, and I still will most likely, but all they had at HobbyTown was ceramic resistors in those resistances, and I don’t know how that’ll work out with how much heat they produce.
Thanks again!
It shouldn't matter what the resistor is made of but you need to look at the wattage rating. I used two 1 amp 10 Watt resistors (one on each speaker). Anything with a higher watt rating is even better (but bigger and more expensive). Don't buy a little 1/4 watt resistor and think you are good. If its low ohm it will burn out instantly.
There is a lot of science and formulas to tell you exactly what wattage is required for a resistor but there is a hack way for a reality check. If the resistor is exposed (like I described in my setup) just make sure it stays cool and doesn't get hot (I did say this was total hack!). Polk uses some 5 amp resistors in their monitor crossovers so I figured I was good with a 1 amp 10 watt resistor (and it was what I had in my parts bin). They stayed cool during my testing so I am thinking they will be OK (but i will keep checking every now and then for now) -
It shouldn't matter what the resistor is made of but you need to look at the wattage rating. I used two 1 amp 10 Watt resistors (one on each speaker). Anything with a higher watt rating is even better (but bigger and more expensive). Don't buy a little 1/4 watt resistor and think you are good. If its low ohm it will burn out instantly.
There is a lot of science and formulas to tell you exactly what wattage is required for a resistor but there is a hack way for a reality check. If the resistor is exposed (like I described in my setup) just make sure it stays cool and doesn't get hot (I did say this was total hack!). Polk uses some 5 amp resistors in their monitor crossovers so I figured I was good with a 1 amp 10 watt resistor (and it was what I had in my parts bin). They stayed cool during my testing so I am thinking they will be OK (but i will keep checking every now and then for now)
OK, I’ll buy some next time I’m over there.
So, I made a mistake. I accidentally bought 1/8th watt resistors. :z I’m assuming I’ll probably blow these up if I get anywhere near 1 watt, right? That was the only wattage they had 1k and 10k resistors in, however I did get 1 watt resistors, although they are 100 ohms and 1k ohms. Will they work? I was under the impression that all that matters is that it is a 10:1 ratio.
I don’t have my second Y-connector, I apparently let my friend borrow it, but I’ll get that tomorrow night.