You went from an Anthem integrated where you could set your subs where you wanted and adjust the output gain on on the Anthem to where you needed it to an Audio only preamp where the gain is fixed and you make the adjustments to the sub amp gain. You end up in the same place a simple fact that you seem to have a hard time understanding. I don’t need to own your same gear to understand the basic principles that apply regardless of brand or model. You don’t want help or advice you just want to make uninformed complaints about an issue that is non-existent.
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Just curious. Why did you go from an Anthem STR to a SGCD? The STR is a great piece of gear.
Come on Jack, why hammer somebody who paid a lot of his money for a PS Audio gear of which the CEO publishes a video at least every week about adding subs. He bought that PS Audio gear and did add a sub per PS Audio’s recommendation, but now gets reel low unsatisfactory sound on the subs and is puzzled.
Like @dtximages I would never, ever split from balanced output. That would defeat the purpose of investing in through tru balanced equipment.
So what’s left are the RCA outputs. Turning the volume up so to standard operate the subwoofer at its worst ratings doesn’t sound very audiophile either.
My suggestion is:
- find a real good match (High gain amplification on stereo RCA inputs) which will be hard to find or one tha has good specs that you can turn up high while still good (not cheap)
- try an old pre amp you have, and connect it between the RCA out of the Stellar and RCA in of your Sub, if that improves you could consider to replace the old big unit by a small brand new pre amp like Schiit Saga S or Saga +.
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There’s just isn’t enough room on the rear panel of Stellar to accommodate dual sets of outputs.
Technically, the XLR are always 6dB hotter than RCA. This is not by “design” to keep the RCA lower, it is because the RCA outs adhere to the industry standards, and proper XLR are by design twice the output voltage or 6dB hotter. Happy to explain why if anyone’s interested.
Chord outputs are typically hotter than industry standards and to my memory, their XLR output is reduced to that it is the same level as RCA. That’s not standard nor is it accepted practice, but there certainly aren’t any “rules” governing this, just industry standard guidelines.
It’s fine to split the outputs and Stellar’s outputs are very low impedance and can easily drive two inputs (which is exactly what would be happening had we the back panel space to add another set of connectors. They would simply be in parallel - same as what happens with a splitter).
Our preferred method of connecting a subwoofer is through high level connections via the speaker binding posts, though we understand not every subwoofer offer this luxury.
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Given that a Line level sub output will be tracking the preamp volume control, you would expect the output to be low and requiring use of gain control on the sub to hit the correct level.
Also plus one for RCA vs XLR balanced outputs - the 6dB difference is as it should be and is entirely correct for the tech. Designing a device that differs from that requires more components, and to not follow industry standards.
With respect, gently: you have no problem with the equipment, just your understanding of how it is supposed to work.
I can’t speak for AV equipment - that is domestic consumer equipment and the manufacturers in that space just do what they want with little regard for industry audio standards.
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@Paul a long detailed piece on gain structure within an audio chain might be a very useful FAQ - a lack of understanding of this crucial subject seems to be at the root of many of the misunderstandings and questions on here 
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Yes 6dB is indeed normal between single ended RCA and balanced XLR. So a Subwoofer’s amplifier has got able to provide 6dB more gain on the RCA inputs and this typically means you need to set the gain higher in such configuration. I guess @dtximages understands that.
But if I understand @dtximages correct the real problem is that the RCA of the particular Stellar Gain Cell DAC outputs way lower than 6dB compared to XLR and consequently the amplifier of his Subwoofer seems not to be able to bridge that larger than 6dB gap.
I don’t know if @dtximages measures this all correctly or if the input impedance of the amp of the sub is so low that it pulls down the signal, but more investigation into the output signal and the input impedance of that particular case would be useful.
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Fair comment - details and measurements would help here to either set the gear up correctly, or indeed identify if there is an issue with this particular amp
I have my subs run SE and mains amp XLR from an ARC pre, and the subs are nearly all the way up. I guess you could also argue that the sub makers should build in more gain.
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I love this forum, by reading these issues it helps me to look at what is important to look for when buying a Subwoofer to pair with the Stellar Gain Cell DAC in my home office.
It can not be a categorical problem with the SGCD, I tried a nice Velodyne with it (RCA output) and my Yamaha monitors (XLR output) at the dealer and it worked fine. I dug up a photo of exactly that situation.
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I think I may be missing something here. I have my subs (ML 10" powered) run from the RCA from SGCD and XLR’s to my monoblocks. I just did the standard sub setup and adjusted the sub output to match the main output. Am I missing something sound quality-wise with this? Am I getting a different DB level from the mains and sub depending on volume? Confusing…
No you don’t seem to miss anything in sound quality. @dtximages who started this thread does. For details please see above in the thread.
A balanced signal passing through a balanced Y splitter remains balanced.
There is no loss of signal using a Y splitter to a sub. The input impedance of the sub is so high only a minuscule amount of current flows, if any. The sub’s input is essentially only taking measure of the signal.
Depends if both loads are balanced, yes. If the sub has only single ended RCA input the signal will certainly not be truly balanced anymore, only if the input impedance of the subwoofer would be infinite, which I expect in @dtximages case it not is, seen the claimed low output.
Even in case both loads are balanced, the input impedance of the mono blocks/active speakers and the subwoofer will likely change with frequency each in a different way, which will I expect have a small impact, but it has.
Also I did not spend weeks and months to search for the Stellar Gain Cell DAC to connect cheap adapters with additional contact resistances between my expensive cables and the expensive SGCD.
You might probably be right that I wouldn’t hear the difference as it might al be marginal. But if it is, why the big fuzz about cable quality.
I am not saying I am right or you are wrong, the adapter stuff just is against my idea of having purchased high end (OK, budget line high end) equipment.
Hope this explains.
The initial comment/complaint was a concern that the SVS sub had to be adjusted to close to -10db to 0db, and it was inferred that adjusting THAT SETTING was a problem. The complaint was not that after adjusting the sub there was not enough output. Looking back, it was not mentioned whether there is or is not enough output after adjusting the sub’s volume to -10db to 0db with his system. According to SVS, these settings are within the operating range of the SVS subs and should not cause any operational issues as long as there is enough bass output after adjusting the settings. They had a recommendation that if there is still a problem with not enough bass output to then adjust positioning of the subs.
I have a SGCD and M700 monoblocks, and had svs subs connected with y adapters from the rca outputs of the SGCD (setting on my SVS sub was -18db to -16db). I switched to balanced cables between SGCD & the M700’s and then adjusted the output level of the subs to between -6db & -3db (as I knew beforehand that I would have to readjust the sub volume higher), and my system sounds seamless and simply wonderful (svs subs connected via rca, no splitter anymore).
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No, the sub’s impedance is so high it has absolutely no impact.
As to your other point, yes if a balanced output is connected to a single-ended input the signal is no longer balanced.
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Hi Elk I think we are in agreement.
If the sub’s impedance is high I already said it doesn’t matter much, but it seems that is not the case with @dtximages subwoofer. He/she utilises the SGCD RCA and therefore I assume the RCA inputs of the sub. So either the input impedance of that sub is low or there is something wrong with his SGCD RCA output stage. Or the sub’s amp can’t bridge the 6dB gain required to keep up with the XLR connected powerstage/speakers like BadBeef suggested.
Rudolf
Your making a lot of assumptions and inferences about other peoples gear as well as what they wrote means just for the sake of continuing this discussion. He has been told by people with decades of audio experience as well as Paul himself that his experience is normal. This now includes other owners of both the SGCD and SVS subs. It is now up to him to do the research and either accept it or change gear and move on.
My opinion is that @dtximages was misunderstood. Telling people what to do or shut up like you seem to like to do puts customers of PS Audio off this forum. Why do you feel you need to police these threads?
The RCA inputs of a sub are also very high impedance, just like an amp’s input.
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