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Michael McBroom

What do you use to power your monitors?

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Buses can only have one output. Adding another bus won’t help because then your sub buses would not be routed there. So you insert a send on the master buss  just like when you add a send to a track. That send can be routed to 3/4 and will control the level of the sub. That way you don’t need to disturb the cat who probably will leave anyway!  

I’ll try and take some screenshots later. 


Even-on huge PA systems subs are always mono. Mine have the 2 RCA inputs but they are summed to mono as it’s only a mono amp in there like all of them.
A Y cable will work  but if your bass and kick are in the middle it won’t make any difference.
It might be more critical for crazy electronic music but sub frequencies are generally mono and none directional. 

Edited by Cactus Music

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On 9/13/2022 at 12:33 AM, Starship Krupa said:

It's a really easy mod, all you need is a pair of flush cutters. You clip out 6 small diodes.

Haha! I enjoyed watching your relentless politeness to the snotty gearhead who felt that you didn't know what you were doing and ANY difference one could hear MUST be measurable. Apparently, he is unaware of the fact that the entire audio industry is based on the belief that some people can hear things that are not measurable and that other people cannot hear. The whole thread is over my head, but I sensed some geeky passive/aggressiveness there.

UPDATE: In his latest post he describes the horrible inconvenience of not knowing exactly when the mail carrier drops the newspaper in his mailbox. He has rigged an alarm system that buzzes in the house when the mailbox door is opened. Who wants to bet he also has a home weather station, and periodically challenges the forecasts he sees on the nightly news?

Edited by Larry Jones
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11 hours ago, Larry Jones said:

Haha! I enjoyed watching your relentless politeness to the snotty gearhead who felt that you didn't know what you were doing and ANY difference one could hear MUST be measurable. Apparently, he is unaware of the fact that the entire audio industry is based on the belief that some people can hear things that are not measurable and that other people cannot hear. The whole thread is over my head, but I sensed some geeky passive/aggressiveness there.

UPDATE: In his latest post he describes the horrible inconvenience of not knowing exactly when the mail carrier drops the newspaper in his mailbox. He has rigged an alarm system that buzzes in the house when the mailbox door is opened. Who wants to bet he also has a home weather station, and periodically challenges the forecasts he sees on the nightly news?

Good to see you around, Larry!

Sheesh, yeah, he had nothing better to do than attack the credibility of someone who was trying to help people with RA-100's, and that's sad. He could have chosen to examine the schematic and figure out whether it was possible for the protection circuitry to affect the audio; after all, it only "requires a basic understanding of discrete transistor circuits." That would have contributed to the topic. But it's not about contributing anything useful, it's just trying to take someone else down a peg.

You notice that he bragged about how his output protection circuit worked for decades? Well, duh, I mean, that circuit is only in there to protect your power output stage in case of abuse, like shorting the speaker wires and turning it up. The best protection is not abusing your amp in the first place. Turn the power off before you repatch. If you repatch and no sound comes out, don't turn up the volume in the hope that sound will come out if you just dime it. 😄

I suspected that I would attract a pedantic hater or two, due to the fact that it was my first ever post in the forum, and that's a flag for certain types to go on the attack. Since I hadn't previously "proven" myself, I'd naturally get a "who the hell are you?" So I was ready for him. The best torture you can deliver upon someone who's trying to pick a fight is to not take their bait. I appreciate that you found it "relentless." 😂 "Oh good sir, I bow before your greater knowledge and will keep you talking until you yourself reveal that you're full of crap." It was Socrates' favorite ploy, and it pissed off the powers that be so much that they had him put to death. His final jab was to say "a life unexamined is not worth living" and slam the cup of hemlock.

It's not about "belief," either, at least on my part. I'm very skeptical about things like this, and I would love to believe that all solid state power amps are created equal. To learn otherwise complicates things that I would rather not have complicated. I'd rather handwave any possible differences between hardware as inaudible, but my ears betray me, even at age 61. Who wants to be concerned that their audio gear isn't giving them the best performance that they are capable of hearing? I just want it all to work.

As for measurable results, at least in this case, I could probably find them if I knew what to look for. There's this school of thought in audio circles, it's the other side of audiophile lunacy coin. It says, like this guy did, that if you can't measure it, you can't hear it. Which assumes that when measuring something, you know what to look for, that your measuring equipment isn't pulling a Heisenberg on the unit under test, etc. There are all sorts of things that can happen in an amp that can't be measured by putting a sine wave or square wave into it and examining the difference between what's going in and what's coming out.

It also tends to assume that any amp that was designed by someone who worked at a company and was mass-produced is somehow automatically properly-designed, and designed to be neutral. Having worked in the electronics industry, I have no idea where this trust comes from, but whatever, it's a trust that I definitely do not have.

Here are the published specs for the RA-100:

  • THD: 0.05% THD @ 1kHz (8 ohms), 0.19% THD @ 1kHz (4 ohms)
  • Frequency Response: ±1dB 20Hz - 20kHz
  • Noise: 100dB below full output
  • Damping Factor: 200 @ 8 ohms

You can get that by, as I said, running a sine through it and comparing the results. It says nothing about intermodulation distortion, group delay, phase distortion, slew rate, transient response, crosstalk, any number of factors that have been scientifically proven to be audible. We test amplifiers with simple sine waves and square waves, but we listen to them with incredibly complex material with a wide dynamic range. A  sine wave tells you nothing about how well the amp will respond to something like a cymbal crash, except that it will be able to deliver the highest audible frequencies. That information could be smeared like crazy if the amp has phasing or intermodulation distortion issues. If it has group delay issues, the different frequencies could arrive at slightly different times, all in various states of in or out of phase.

55 years ago, people still believed that it was impossible to hear the difference between tube amplifiers and solid state amplifiers, that if anything, solid state amplifiers should sound "better" because they had greater frequency response and less measurable distortion. People who claimed otherwise were accused of magical thinking. And as we know, "magic" is sometimes "science" that hasn't been explained yet. Now we know why tube amplifiers, for instruments as well as hi-fi, can sound objectively better depending on the application. Part of why we know this is that so many people preferred the sound of tube amps that we got busy and figured out why that is.

I've previously experienced this with computer audio interfaces. I happily used a pair of Presonus Firepods for about 8 years until one fateful day I found a Presonus Studio 2|4 on Craig's List for $30. The idea for getting such a small interface was to have something to use with my portable devices. I hooked it up to my main DAW system to test it and....OMG. The stereo image sounded like it extended about 2' past the outer edges of my monitors, sounds in the middle had better Y-axis image, I could hear all these little sonic details in the background....

So I went online and did a deep dive into how this could be possible. It was just playback, which should have sounded identical; the big difference in audio interfaces is the input preamp circuitry....right? Because everyone "knows" that all that DAC's do is convert those ones and zeroes into audio, and since the THD is negligible and the frequency response extends beyond what dogs can hear, any differences are due to placebo effect from my having a shiny new toy.

Well, a Gearspace thread from around 2010 from a Presonus representative mentioned that the Firestudio, which had just come out and was the successor to the Firepod, would sound way better mostly due to the introduction of "JetPLL" to the clocking system. Which led to my discovery of this paper from the inventor of JetPLL, which has been standard in prosumer interfaces since it was introduced around 2010. Turns out that people can hear differences in jitter, it's measurable and audible. Here's Presonus' ad copy regarding the Firestudio's introduction of JetPLL:

"JetPLL™ ensures the highest converter performance possible, resulting in better stereo separation and clearer more transparent audio." Which is exactly what I was hearing, before I saw their ad copy.

I even found an old page on Presonus' site offering factory trade-in credit on Firestudios for owners of Firepods. I guess they didn't want them out there.

Anyway, it was so audible to me that I unplugged the Firepods and went in search of an 8-input Firewire interface from the JetPLL era. Found a new-in-box Sapphire Pro 40, and sure enough, its playback sounds great. Now I'm sure that prior to 2010, all manufacturers claimed that their interfaces played back audio perfectly, and had the test results to show it. So if that were the case, why does every mass-produced interface made since then include a JetPLL chip? It's not as if manufacturers go in search of licensed technology to add manufacturing cost to their products. Turns out that a stable clock is critical to a DAC's audio performance and that clock stability took a huge leap in the late 00's.

I don't like to play this card online for various reasons, but I've been a professional instrument amp repair guy for 15 years. Had to retire from it due to health reasons. I've designed and built guitar amps, both for my own use and on contract for other companies. One of my products was very favorably reviewed in Guitar Player magazine. Before I had my own company, I worked in the engineering departments at a variety of audio companies, including Orban Associates and Nady Systems. In my early Silicon Valley days, I laid out integrated circuits using the old amberlith-and-xacto-knife method.  I am not a newbie hobbyist at electronics.

One of the reasons it's not good to play that card with someone like that poor fellow is that they'd only come back at you with "well if you have all that experience then you must know...." It would just be playing their one-upmanship game. I don't need to flash my cred.

If you were in my area, I could hook up both my modded and unmodded RA-100's and you would find the difference stunning. You'd have no trouble with a blind A-B test.

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2 hours ago, Starship Krupa said:

The best torture you can deliver upon someone who's trying to pick a fight is to not take their bait.

Yes, no point debating in a case like that. It's like trying to convince folks with certain completely unsupportable political beliefs by citing facts.

2 hours ago, Starship Krupa said:

If you were in my area, I could hook up both my modded and unmodded RA-100's and you would find the difference stunning.

I am a virtual million miles from everything, but one never knows: Where is your area?

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What you really need is a proper power amp designed for the job and not home stereo stuff. As you have discovered, what you have is lying to you.

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The ns systems (ns 10s etc.) were designed as proper pro monitors including their accompanying amps.  But they got sold as bookshelf speakers for the home.  Didn’t harm the sound.  
 

I put four on the ceiling of a small live theater for sound and they worked fine, even for the bass (this was in the analog days and LPs were limited in the bass).  It was for theater, not a disco.

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Thanks for the responses, guys. I was expecting something like what y'all provided. Now, I guess I need to do a little more homework and see what I can come up with based on what I can afford.   teatv download

hellodear.in
 

Edited by Peache

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I have a couple of sets of powered speakers; connected to a Presonus Central Station Plus for routing and monitoring selection for maximum flexibility  

1 x Pair of JBL LSR2380 & LSR2310 Subwoofer
1 x Pair ADAM A7X
Single Avantone MixCube for Mono monitoring 

I also have an older pair of Kef 2 way driven speakers powered by a fully re-built Marantz SR-96 THX Receiver which I use to test mixes in a home theatre environment. Fully recapped, with beefier transistors in both the preamp and output stages. It’s a very clean sounding amp which I’ve owned since new, though now pushing 30 years old. I had the rebuild done about 15 years ago by a specialist repairer as it had developed a fault which needed quite a bit of work in any case. 
 

All that said some basic room treatment will probably make a bigger difference than speakers and amp. Early reflection points (walls and ceiling) and bass trapping in corners can be extremely helpful and accomplished on a fairly modest budget, especially if you can do a bit of DIY. 

Edited by Michael Vogel

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