100w THD+N of the Purifi 1ET400A modules with a DSP system in the signal chain, rather than a passive crossover.
Speaker dude,
We get that you like Purifi amps and are a believer in active DSP speakers. It’s all in the implementation. I think passive crossovers in the long run sound better and have less noise (they are truly silent) and let me use my speaker with any amp I have. I have a lot of amps and don’t like to have to be constrained to using x channels of amps for x numbers of drivers. I have a lot fine sounding Class A amps that I would rather not make 4 channels to listen to a speaker and have to redo the crossover DSP every time I switch amps.
I came from DSP and active speakers to discovering passive crossovers are better sounding. But that’s just my opinion after building 75 speakers and 50 amps.
Active DSP has its place. Pro sound for example. But for the finest home hifi, I still vote for passive XO’s in a well implemented transient perfect speaker.
We get that you like Purifi amps and are a believer in active DSP speakers. It’s all in the implementation. I think passive crossovers in the long run sound better and have less noise (they are truly silent) and let me use my speaker with any amp I have. I have a lot of amps and don’t like to have to be constrained to using x channels of amps for x numbers of drivers. I have a lot fine sounding Class A amps that I would rather not make 4 channels to listen to a speaker and have to redo the crossover DSP every time I switch amps.
I came from DSP and active speakers to discovering passive crossovers are better sounding. But that’s just my opinion after building 75 speakers and 50 amps.
Active DSP has its place. Pro sound for example. But for the finest home hifi, I still vote for passive XO’s in a well implemented transient perfect speaker.
Can you share some measurements of the DSP systems you compared to the passive crossovers? Also if you look up something called Johnson Noise you’ll discover that passive crossovers aren’t as silent as you think. Also Hysteresis distortion from the inductors can be nasty.
100w THD+N of the Purifi 1ET400A modules with a DSP system in the signal chain, rather than a passive crossover
I presume the DSP unit is before that Purify power amp and the Passive x/o is loading the power amp. How have you loaded the power amp with the DSP in front of it?
Is the load then an 8 ohm or 4 Ohm high power resistor?
I presume the DSP unit is before that Purify power amp and the Passive x/o is loading the power amp. How have you loaded the power amp with the DSP in front of it?
Is the load then an 8 ohm or 4 Ohm high power resistor?
There is no passive crossover in the signal path. Otherwise we wouldn’t see a measurement this good. But there is a 4 ohm dummy load.
Dude,
I know what Johnson noise is - I don’t think it is an important thing in speaker level crossover resistors. Has anyone complained that the Johnson noise of their crossover is audible?🤣
I have tons of measurements of my DSP speakers on DIYA going back to 2013 or so. If you are interested there’s a great search function…
More recently, I have developed active DSP systems for commercial speakers. An ADAU1452 and a very good AKM ADC in and AKM DAC out. Still far from silent.
Besides measurements, my ear is the final test. I have yet to hear an active DSP system that is absent a low level hiss. My passive speakers on the other hand, paired with a good amp - I literally cannot tell they are turned on with my ear pressed to the speaker cone.
I think we are all trying to learn here and help each other. You might check your tone as it’s a bit caustic and arrogant. One of your common responses to anyone asking a question is an ad hominem attack “what have you done and show us your build”. Well, I don’t think we have seen your builds. What have you built?
I know what Johnson noise is - I don’t think it is an important thing in speaker level crossover resistors. Has anyone complained that the Johnson noise of their crossover is audible?🤣
I have tons of measurements of my DSP speakers on DIYA going back to 2013 or so. If you are interested there’s a great search function…
More recently, I have developed active DSP systems for commercial speakers. An ADAU1452 and a very good AKM ADC in and AKM DAC out. Still far from silent.
Besides measurements, my ear is the final test. I have yet to hear an active DSP system that is absent a low level hiss. My passive speakers on the other hand, paired with a good amp - I literally cannot tell they are turned on with my ear pressed to the speaker cone.
I think we are all trying to learn here and help each other. You might check your tone as it’s a bit caustic and arrogant. One of your common responses to anyone asking a question is an ad hominem attack “what have you done and show us your build”. Well, I don’t think we have seen your builds. What have you built?
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AD: So you compare a dummy load of 4 ohm instdad of a real speaker as load with a x/o over loaded amp. Exactly as I assumed= apples vs oranges.
If you have some measurements to share on the DSP/amp setups you have experience with please share. I’m not doubting that your subjective experiences with what you have experience with are honest. But nobody can hear what your ears can hear over the internet. So the best we can do is provide measurement results.
And no that’s not what I said to the member. Don’t twist it out of context. I asked him to share his Purifi build because he wanted to talk about Purifi builds. And I even said please.
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I've mainly built active systems and it can be done, but the whole design has to contribute to get there. I had a Najda DSP with analogue volume control and UcD amps and they were silent on the LX521. But you are right that most active implementations suffer from tweeter hiss. In a desktop system that is annoying but once you are a few metres away it has to be pretty bad to notice it when any programme is playing. Of course once you have hard it you know it there and can fixate on it 🙂
So you’re saying a speaker load is tougher on an amp than a constant 4 ohm load? Besides the point is that the passive crossover messes up the performance of the signal before the load. This isn’t an amp performance test.
Hi!
Could you please send me some details/specs of your DSP system? Very interested. Thanks!
I clearly heard hiss from nCore 125W through 130dB horn here, so I added -6dB resistors between amp and driver. I still hear noise though.
Best to go with Purifi. But make sure the DSP isn’t the bottle neck. The only performance that matters is total system performance before the drivers. This is how to make the best from a Purifi driver build.
What shocks me is an old man in his 70’s back in 1996 already knew DSP was the best way to build speakers. And 25 years later few have caught on still.
I highly recommend reading that Stereophile article on John Dunlavy I linked to a few posts back
I highly recommend reading that Stereophile article on John Dunlavy I linked to a few posts back
Oh and the resistors can add even more noise and distortion. For example these resistor dummy loads from Parts Express are useless for measurements beyond -92dB THD+N. Johnson noise and distortion dominates beyond that.
https://www.parts-express.com/4-Ohm-100W-Non-Inductive-Dummy-Load-Resistor-019-015