Connecting RCA out from amp to LFE input on Sub ?

[Punit Shetty]

Hi,

I have a pair of Polk LSI9's hooked up to a NAD C 375BEE Integrated Amplifier.
http://nadelectronics.com/products/hifi-amplifiers/C-375BEE-Integrated-Amplifier

I want to add a subwoofer & was think of buying the Definitive Tech ProSub 1000 as am getting a good deal for it.

http://www.definitivetech.com/Products/products.aspx?path=Subwoofers&productid=ProSub%201000

The sub has only LFE input with a variable low pass crossover from 40 Hz – 150 Hz. Can I connect the Tape Monitor RCA out from my amp (using a Y cable) to the LFE input of the Sub ?

Thanks

[markw]

Technically it'll work but you will have absolutely no control over the sub's volume from the amp.

Assuming your sub has preamp outs, you would be better off using them. Since that's a NAD, I think that's a pretty good assumption.

At most you'll need a couple of "Y" connectors that split off a signal to the sub while maintaining continuity between the pre and main amps.

[edit] Oops... I see now the sub has only one line level input. Bad choice for a stereo system.

For use in a stereo system without a sub output you need a sub with both right and left line-level inputs.

In your case, you'll need to use the subs speaker-level inputs to realize the full benefit of a subwoofer.

[Hyfi]

Technically it'll work but you will have absolutely no control over the sub's volume from the amp.

Assuming your sub has preamp outs, you would be better off using them. Since that's a NAD, I think that's a pretty good assumption.

At most you'll need a couple of "Y" connectors that split off a signal to the sub while maintaining continuity between the pre and main amps.

[edit] Oops... I see now the sub has only one line level input. Bad choice for a stereo system.

For use in a stereo system without a sub output you need a sub with both right and left line-level inputs.

In your case, you'll need to use the subs speaker-level inputs to realize the full benefit of a subwoofer.

Not 100% true. I was told by the owner of RHB, which is a local Tube Gear customization shop, that both channels have close to the same LF and one is all that is needed to run the single rca input sup. My pre-amp is dual mono and I cannot use a y splitter as it forces all output to be mono in my setup. But, I run 1 sub cable from one channel pre-out of my VAC to sub and have no issues.

[markw]

The operative words here are "close to". If those words weren't there I'd go along with you. But they are and that significantly modifies the following words to mean NOT the same.

Would you want that?

With all the talk about stereo subs and directional bass nowadays, I wouldn't.

[Hyfi]

The operative words here are "close to". If those words weren't there I'd go along with you. But they are and that significantly modifies the following words to mean NOT the same.

Would you want that?

With all the talk about stereo subs and directional bass nowadays, I wouldn't.

I paraphrased from the conversation I had with the guy, he may have said "Same". Anyway, my suggestion gets the guy up and running without having to purchase anything.

[markw]

I paraphrased from the conversation I had with the guy, he may have said "Same".Whatever...



Anyway, my suggestion gets the guy up and running without having to purchase anything.Really? How would he get the signal from theamp to the sub without a cable? Aside from speaker cables, so does mine. And he'll be assued of all the bass going to the sub.


Anyhow, this subject is done. He can make his choice.

[Hyfi]

Whatever...


Really? How would he get the signal from theamp to the sub without a cable? Aside from speaker cables, so does mine. And he'll be assued of all the bass going to the sub.


Anyhow, this subject is done. He can make his choice.

Talk to Mtry lately?

I assumed he had an interconnect to plug in and he wouldn't have had to purchase Y connectors to get sound from the sub.

[Punit Shetty]

Thanks for the suggestions guys.

[D. Paul Navigator]

Hi,

I have a pair of Polk LSI9's hooked up to a NAD C 375BEE Integrated Amplifier.
http://nadelectronics.com/products/hifi-amplifiers/C-375BEE-Integrated-Amplifier

I want to add a subwoofer & was think of buying the Definitive Tech ProSub 1000 as am getting a good deal for it.

http://www.definitivetech.com/Products/products.aspx?path=Subwoofers&productid=ProSub%201000

The sub has only LFE input with a variable low pass crossover from 40 Hz – 150 Hz. Can I connect the Tape Monitor RCA out from my amp (using a Y cable) to the LFE input of the Sub ?

Thanks

It's really not that hard to wire the sub in. I'm adding a url to Radio Shack with reversed Y connector (stereo to monaural). Use your preout #1 run two cables down to the reverse Y at the subwoofer. The Y has two female connectors to plug into, and the other end plugs into the sub LFE, and you're good to go. By the way I have the Prosub60 which has both the LFE and two active inputs. I wouldn't recommend this setup for your amplifier for the previous stated reasons, you have no volume control on the Def Tech (which is sad).

http://www.radioshack.com/product/index.jsp?productId=3295840

[markw]

It's really not that hard to wire the sub in. I'm adding a url to Radio Shack with reversed Y connector (stereo to monaural). Use your preout #1 run two cables down to the reverse Y at the subwoofer. The Y has two female connectors to plug into, and the other end plugs into the sub LFE, and you're good to go. By the way I have the Prosub60 which has both the LFE and two active inputs. I wouldn't recommend this setup for your amplifier for the previous stated reasons, you have no volume control on the Def Tech (which is sad).

http://www.radioshack.com/product/index.jsp?productId=3295840You do realize that by joining the right and left channels at the preamp out will result in the entire signal being converted to mono, not just that to the subwoofer, don't you?

[D. Paul Navigator]

You do realize that by joining the right and left channels at the preamp out will result in the entire signal being converted to mono, not just that to the subwoofer, don't you?

Actually you're correct for the preout #1, you join the two into one signal which is what you want. I doesn't affect the output to your main speakers at all. I've been using this set put for years, what were you expecting?

[markw]

Actually you're correct for the preout #1, you join the two into one signal which is what you want. I doesn't affect the output to your main speakers at all. I've been using this set put for years, what were you expecting?Well, your experience is different from others who have tried this, including mine. The preamp outputs are joined, simple as that, and the combined signal goes both to the main amp and the sub.

This isn't water where it only flows downstream.

It's possible that some outputs might be buffered but it's not something one can count on. What preamp are you using?

[D. Paul Navigator]

Well, your experience is different from others who have tried this, including mine. The preamp outputs are joined, simple as that, and the combined signal goes both to the main amp and the sub.

This isn't water where it only flows downstream.


When you plug a left and right cables into the active input on a subwoofer, those are joined into one signal. Does your friends know that too?

[markw]

When you plug a left and right cables into the active input on a subwoofer, those are joined into one signal. Does your friends know that too?Yes, we do. Do you know how they are combined into a mono signal?

Did you know that when these right and left inputs are fed into a powered sub, before they are fed to the crossover and power amp, they go through a special* circuit that combines the two channels into a mono signal for the sub and still maintains isolation for the the two channels for the rest of the signal chain. It's a bit more complex than a simple "Y" connector.

Did you know that, or were you just assuming it was a simple "Y" connector inside?

*It's a bit technical. Don't worry about it. Just know it works.

[D. Paul Navigator]

I love it, finally fell back on technical reasons for your answer. Special electronics to combine the circuit, never fails.

[markw]

I love it, finally fell back on technical reasons for your answer. Special electronics to combine the circuit, never fails.So, you still say a simple "Y" connector will do it, eh?

Please note that nobody else commented here. They are all watching this, most likely with great amusement.

Of course, OP is certainly welcome to try your solution and hopefully report back to us on the results.

But, before trying that, he might want to read this: Here (http://www.avsforum.com/avs-vb/archive/index.php/t-781811.html) is a little discussion on this subject from another source. There are others but hopefully this will get the point across. Of course, you're encouraged to provide examples where your option worked as well.

[D. Paul Navigator]

No I want do this any more, but if you had said check out the circuit I would have been agreeable the dual input to the sub is different than the "Y". I was wrong, but really irritated me was my recommendation I made was not pursue the sub due to the lack of volume control, which was a deal breaker. However, you were more interested in proving me wrong than looking at my recommendation. Next time just point out my error and ask me to check it out, which is exactly what I did. Then you get a big apology. Have a very nice day, I'm sure there's others you can point out there mistake to them.

[markw]

No I want do this any more, but if you had said check out the circuit I would have been agreeable the dual input to the sub is different than the "Y". I was wrong, but really irritated me was my recommendation I made was not pursue the sub due to the lack of volume control, which was a deal breaker. However, you were more interested in proving me wrong than looking at my recommendation. Next time just point out my error and ask me to check it out, which is exactly what I did. Then you get a big apology. Have a very nice day, I'm sure there's others you can point out there mistake to them.What you're railing about here has nothing at all to why i responded to your posts.

Now, you're just flinging bull. I never sad anything about a volume control in response to your post. To the OP, yes. You really couldn't see that? All I said about your post is that reversing a "Y" splitter is not a good idea and If that was too complex for you to understand, I apologize, but I really couldn't dumb it down any more.

Your only input here was to use a reversed "Y" connector and, point blank, you were wrong. Add to the fact that you refused to admit it or, even worse, try to explore why I said what I said. You had to wait until I spoon-fed it to you. Face it, you came to a battle of wits unarmed.

Are you delusional as well as arrogant? Do you think we're really that stupid to not be able to see exactly what you posted in this thread.

But, what I find really curious is this snippet from post 11 here.


Actually you're correct for the preout #1, you join the two into one signal which is what you want. I doesn't affect the output to your main speakers at all. I've been using this set put for years, what were you expecting?

Here you say that you've been using a reversed "Y" connector for years.

So, in the current post you admit you're wrong and yet, here you say you've been using a reversed "Y" splitter for years. Which should we believe?.

You're off to a really good start. Keep in mind that there's a LOT of us here who know a heckuva lot more than you ever dreamed of. If you're going to continue to post here and this exchange is any indication of your technical knowledge, you better get used to being called out when what you say is wrong or, even worse, potentially harmful.

Enjoy. I'm sure we'll meet again.

By the way, it's "their", not "there" in your last sentence.

[D. Paul Navigator]

I used the Y adapter years before, to connect both the L and R from one source. It was in vogue years ago, and without thinking through what I had done previously, I made a mistake. What I don't need is you making judgments on my background or my spelling. If you feel like beating your chest do it, but be careful of making threats to me or about me, or calling me names like stupid.

[markw]

I politely, and quite nicely, non-judgmentally, and non confrontationally I might add, pointed out a basic error in your advice.

You're the one that chose to get all huffy and defensive about it, not me, particular in post 13 and beyond.

And, I never said you were stupid, merely mistaken. You're the one that's using the word. ...but I won't argue with you on this one.

[Hyfi]

Actually you're correct for the preout #1, you join the two into one signal which is what you want. I doesn't affect the output to your main speakers at all. I've been using this set put for years, what were you expecting?

This method screws up my VAC dual mono pre amp. If I take a L-R into one (y-cable) to the sub, it somehow shorts all output regardless of the source or whether it's pre out 1 or 2. My mains turn mono and 1 volume pot controls both. With my sub, I am forced to just run a single pre out L or R to the sub. You would be hard pressed to tell me anything is missing.