2. cables
  3. 167869-11005

I really could use some help here.....

This is a hopefully finely detailed question that gives the people who are seriously trying to help me all the info they need to answer this question which is about cables, routing and speaker connections. Hopefully I can explain it well enough that someone can tell me what I have done.

The connections are ONLY RCA jacks and banana clips. That's all. Let me describe how I have wired things.

Source signal is from an OPPO Digital BDP-105 running to the CD input on my preamp via RCA jacks. Simple.

The signal leaves my preamp via Preamp Out connectors, also RCA jacks, and runs to my Sunfire SDS-12 subwoofer which has two line level RCA jacks for input so you can make use of the hi pass filter built in. That is the easy part, here is where it gets tricky ( for my understanding anyway...this is where I need your help in understanding the circuit I created  and if it makes any difference at all ).

The signal leaves the Subwoofer via the RCA jacks using the Subwoofer Out connections and goes to my RCA jack inputs on my amplifier ( all this makes sense to me so far, here is where I need help understanding )...the amplifier has banana clips for the connections to the speakers. RIGHT THERE, I change things. I have Monitor Audio speakers that can be bi-wired or bi-amped and when I bought them, the fellow through in a pricey set of cables allowing me to do that ( this is BEFORE I added the subwoofer to the system  ) so the signal finally leaves my amp via 2 banana jacks and arrives and terminates at my speakers in with 4 banana jacks and plugged in using the bi-wire configuration. Am I clear in describing this, Christ I hope so.

If I am, can anyone tell me what that that circuit looks like sonically, what's going on with all the other connections, what the Hell am I hearing? 

In short, I originally had just normal preamp/amplifier connections then bi-wire straight to the speakers.

Now I have introduced that subwoofer pathway into the signal path between preamp and amplifier? I'd love serious explanation on what that did, if anything, to the signal. My hope was that it was going to make the subwoofer and amplifier more in sync than if I'd run a separate connection from my second Preamp Out to the subwoofer. This way it's all in one signal path. So, is this the optimum way to set this up? Or have I screwed this up somewhere and it should be connected a different way?

Thank you so much!

For others, please stop calling my gear "junk" and I should sell it all and by REL. You're not helping any and you're giving a bad reputation to Audiogon people who are seriously trying to help me.

Components
1993 B&K Sonota ST-202+ amplifier fully refurbished
1993 B&K Sonata Pro-10 MC preamp
2008 Monitor Audio Silver RS8 speakers
OPPO Digital BDP-105 Blu ray player
2018 Sunfire SDS-12 subwoofer

I hope I've given enough information for people smarter than me to tell me if I have things connected in the best fashion and I'm hoping someone will take a few moments to answer.

Thank you.

j


Please do not pop in to suggest I spend $6,000 on all new gear while insulting me. This is what I have to work with so that's how it will stay. Thank you.

stereoisomer
elliottbnewcombjr
5,529 posts
 
You smartly improved your system, with the kind of sub I prefer: front firing.

I now encourage you to consider a second sub, locate them forward facing adjacent to the main speakers to achieve localization of bass instruments. It is the primary i.e. 30 hz, and the overtones: 60, 120, 240, ... that give localization of the bass notes.

as other's have said, you have used the sub's crossover to best advantage, letting the sub take the low bass job, sending only upper bass, mids, highs to your amp which continues to power your speakers in a bi-wire method.

just to clarify: the crossover (in the sub in this case) is not a specific frequency point, i.e. 60 below here, 61 above there. Using the dial, you choose the precipice of a SLOPE: beginning a gradual reduction of volume (strength of signal passed/sent) that will be sent back to the primary amp.

In your case your amp doesn't need a break, but the speakers do, they no longer try to make low bass, and your ears get the gift of extended bass from the sub and lack of distortion from the mains. Lower powered amps than your's benefit the most as they don't have to produce low bass. It's a great way to allow tube amps of moderate power to succeed. 
classdstreamer's avatar
classdstreamer
172 posts
 
@stereoisomer 

I think you articulated yourself well in this thread. The way I conceptualize engineering and the audio reproduction hobby is that we are often making compromises rather than across the board improvements--getting one benefit by giving up another. You articulate two options here. But, I see a third option given your gear.

Now I have introduced that subwoofer pathway into the signal path between preamp and amplifier? I'd love serious explanation on what that did, if anything, to the signal. My hope was that it was going to make the subwoofer and amplifier more in sync than if I'd run a separate connection from my second Preamp Out to the subwoofer. This way it's all in one signal path. So, is this the optimum way to set this up?

You consider either (1) running the sub and mains power amp out of separate preamp outs, vs (2) adding the sub to the chain so that it the mains power amp receives only the higher frequencies. As you and others have stated, both are viable options. The third possibility (3) is that you keep the sub in the signal path but defeat its high-pass filter. 

Looking over your sub's manual, I see that you can defeat the high-pass filter by "by rotating the crossover frequency control fully clockwise." 
https://pdf.crutchfieldonline.com/ImageBank/v20150208141700/Manuals/877/877SDS12.PDF

You state that your goal was to "make the subwoofer and amplifier more in sync." Like you, I am also sensitive to the lag time of the bass frequencies. In my system, I use (1) because it's the only option with my sub, integrated, and room. It's better than no sub, but the sub frequencies arrive late. (One writer on the Darko forum states that latent subs are common, but certain brands make faster subs to remedy latency. See https://darko.audio/2021/06/kih-89-mind-the-gap/.)

So, I think (2) may help you to achieve your goal better than (1) by placing the sub prior to the mains power amp in the signal path and getting those sub activating earlier vs the mains. However, I believe that (3) is also worth a try because, in theory, you may retain the sub's priority in the signal path, but you can have the added benefit of allowing the mains to produce sub frequencies too. That is, you have a multi-sub system of sorts with better timed bass. The downside to (3) may be that, with your specific sub, defeating the high-pass also requires your sub to play the entire range from 30-150hz. So, you might find that when overlapping frequencies with your mains, you may get too much sound from 60-150hz, say, and not enough from 30-60hz. 

Tying back into the initial thought about engineering often being a game of compromises, I see the two prevailing sub setups as compromises. Connecting subs via speaker cable allows for better integration with the mains, and allows for a focus on sub latency. And connecting subs via RCA gives up that integration with the mains for smoother bass response in each seating position and across more seating positions, and can free up power on the mains amp.
peterf6
74 posts
 
I don't think anyone addressed this part of your question explicitly yet. Regarding the bi-wiring, you are still getting that benefit if the frequency of the speaker crossover is higher than your subwoofer crossover. So if you are only sending above 60HZ to the main amp (taking into account the slope issue of the previous comments) and your main speakers cross over around 2K, then everything from 60-2K are going through one wire and the higher frequencies go through the other.

You're lucky that you got a great improvement right off the bat. Subwoofer placement, crossover point, and volume should provide you loads of tweaking opportunities, too!

Enjoy, and I second the complement about encouraging civility.
peterf6
74 posts
 
@asvjerry FYI, I only recently bought a pair of speakers that are made to be biwired, so I researched why something so odd could work. My Totems sounded different to me biwired, and this research provides an explanation beyond "listen to the difference." https://www.qacoustics.co.uk/blog/2016/06/08/bi-wiring-speakers-exploration-benefits/

tomic601's avatar
tomic601
12,957 posts
 
Biwire done correctly is about two things:
the larger field from bass signal can be moved to a different set of wire and physically spaced ( 4” is a good place to start ) so that field does not modulate the HF signal. The second thing is the crossover in the speaker extends back to the amp from an electrical perspective. Many listeners and competent speaker designers provide biwire provisions for a reason.
you have more options to explore in hooking up your system. ( and learning to discern Sonic differences ) For example just doubling up the biwire and using jumpers and listening…. You should also experiment w that second set of preamp outs - you are betting all your sonics on the quality of filters iMO  implemented in your sub.
have fun
enjoy
jim
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