newbie overwhelmed with subwoofer connection...

[alias4cat]

...among other things.

I am still working on creating (at this point, I'm just trying to make the system work) my first 7.1 surround sound system. I know just enough to get myself into trouble, and to ask questions when needed, but right now I'm in the frustrated zone. Please be kind, as I am a sub-par newbie whose most recent endeavor was to create (and run under the house) speaker wire using 10 gauge Belden cable/compression banana plugs (a first for me). This system is an upgrade from my old 2-channel Nakamichi.

Here's what I have:
Receiver: Denon AVR-3805
Fronts: Mirage OM-7 towers
Middle sats: Mirage MBS
Rear sats: Mirage MBS-2 (currently crossed with Mirage BPS-150 sub)
Center: Mirage MC-si

Plus nonHD tv, DVD, CD player and other stuff that is not an issue...yet.

Thus far, I've wired the front speakers and the center channel (okay, I did the easy stuff first) to the receiver. Now I want to connect the rear sats. I have the subwoofer located at the back of the room, crossed with the sats. Instead of crossing, I had thought that I would just run speaker wire separately from the 2 sats and the sub to my receiver.

Looking at the back of the receiver, there is no input location for that setup, so obviously I'm on the wrong track. I can see where the sats will go, but the receiver sub connection is a single RCA type plug-in. Right above that is the center channel RCA input. There is no LR dual interface (?). The manual doesn't address this directly; it shows a diagram with a single connection jack for a sub with built-in amp (which is what I have).

Sounds simple, but I am not sure if this is what I need. On the back of my sub, there are two options for connection. One is the "high level" connection block, containing four pairs of speaker terminals. This is what I have used in the past for x-over with the subs. The other option is for "low level" connections, but here I still have four (LR, red and black) RCA connections. So how do I translate 4 into 1? And if I connect just one, which one? And will I be losing sound quality?

I'm sure this is an elementary question, but I am lost--and depressed, because I want to move forward and get this system running. Help? I'm really over my head here. Not giving up though....

One more question, if I may...if I am to use an RCA connection...what is the basis of that cable? I will have a 50 foot run for the rear speakers (under the house) and buying one from Rat Shack won't do. Can I create one from my 10 gauge, by just using RCA terminations, or is that a whole different animal?

Thanks,

--cat

 

[t3031999]

You will need to use a subwoofer cable with RCA jacks on it.
Depending on your sub you may also need to buy a Y-splitter to connect the RCA input to both red and white inputs on the back of the sub.

You can either buy a subwoofer cable from blue jeans cable here

or you can make your own.
No you can not use your 10 gauge speaker wire as it will have far to much interference since it wouldn't be shielded. I would recommend some high quality quad-shielded RG6 cable with RCA jacks.

Unless you're good with soldering, I would recommend the blue jeans 50 or 60 foot cables.

 

[Resident Loser]

I don't know if...

...locating the sub THAT far away from the front speakers is advisable...The frequencies that it handles are supposed to be somewhat non-directional, but I think there may be some coherence/directional issues in this case...

jimHJJ(...since I don't use, or need, a sub, it's just my ignorant two cents...)

 

[MACCA350]

You can use a signal RCA to connect the Receiver Sub output to either the L or R input on your sub, this is stated in the BPS-150 manual below

cheers

 

[alias4cat]

Thank you all for your advice. I think I am "getting it." I reviewed the BPS-150 manual, (you're right, MACCA350, it was in there all along), along with the BPS-150i manual--which is another reason I was sooooo confused.

I have the 150, which has 4, not 2, low level RCA outputs. I had downloaded manuals for both of the subs. The 150i has only 2 and manual indicates to use a single RCA jack. The 150 doesn't address the issue directly, but it appears I can either use one RCA jack or use a y-splitter to combine R/W into a singe RCA cable, then to my receiver.

I think I'll follow t3031999's advice and order either a 40 or 50' one from Blue Jeans cable, along with a splitter. My room dimensions are 24 long x 12 w, and the sub is located diagonally from the receiver, so I figure at minimum, I'll need 40 feet (I'm tacking down from the receiver, through the flooring, under the house, along the crawlspace walls in a L-shape, then back up to the sub).

Next up is finishing the sat wiring (and under the house again), and trying to understand all the wires (s, component, etc,) for the tv, dvd and so forth. THEN to config the Denon. It's a bit overwhelming for a newbie, but I'm going to keep up with it.

I have no one here at home to ask (well, I did ask some guys at the Rat Shack, but they knew even less than me, go figure...), and I've never dealt with RCA jacks on a sub before, so--again--thanks for being gentle with me and for all the help offered.

--cat

 

[jcPanny]

Sub location

Why do you have to locate the sub on the opposite side of the room? The location of the sub in your room can dramatically effect its performance, so I would recommend experimenting with sub locations before running a 40 ft cable under the house.

Also keep in mind that all powered subwoofers require an AC outlet.

 

[alias4cat]

"Why do you have to locate the sub on the opposite side of the room? The location of the sub in your room can dramatically effect its performance, so I would recommend experimenting with sub locations before running a 40 ft cable under the house."
----------------------

I have an AC outlet close to the sub, so that's not a problem.

As to why I have located the sub at the opposite side of the room...well, I'm open to suggestions or advice why I should change location, but here's the reasons it is located where it is...

TV housing and aux setup are all on the south wall. On L and R of that are the tower speakers. I do not need a sub up there, but do need one to add depth to the sats on the north wall rear. There is no space on the east wall, as it is a large fireplace, then french doors. Half of the west wall is open/walk-through. The towers and entertainment housing unit take up the entire south wall.

The sub is bipolar, and sounds much richer when located in a corner, which also lends to its present location. That being said, am I wrong in how I've placed the system? I mean, there is really no "wrong," but am I losing mucho quality? Towers in front, sats in kinda middle, bigger sats and sub in rear.

--cat

 

[mulester7]

I mean, there is really no "wrong," but am I losing mucho quality? Towers in front, sats in kinda middle, bigger sats and sub in rear.

--cat

.....this is nothing but personal preference, Alias....placing a single sub in the rear of the room would be somewhat unorthodox for me, but some do that and prefer it....subs should be an extension of the other speakers, and a supporting factor of "the soundstage"....there will be a degree of localization with any sub, and with the soundstage in the front of the room, I would not want a sub or subs in the rear of the room....but hey, that's just me......

 

[t3031999]

I don't know the specs of your front towers but the denon may have trouble driving the whole surround set up to loud volumes with the towers set to large. Unless you have your front tower speakers set to large, they will not play anything below the crossover frequency. So you may need the sub up there if you set the mains to small.

One of the best ways to test the position of a sub is to put it in your listening position, or as close as possible. Then walk around to all of the reasonable areas you could place the sub and listen to test tones. Generally where it sounds loudest is the best place, because that will mean that there are the fewest nulls in that position. Be careful because if you can't EQ any peaks you may end up with boomy sound.

So the best idea is to experiment, but to experiment you need a cable. So buy a long enough one.
Before running it under your house find the spot that works best. And then run it

 

[jcPanny]

Purpose of sub

The sub is meant to provide the LFE information for all channels, not just the surround speakers. In fact, most of the sound is comming from the front channels and center, a little from the (side) surrounds and very little and sometimes nothing from the rear surrounds.

On that note, the surround speakers placed on the sides of the room contain more information and are more important than the rear surrounds, so place the larger or better performing speakers on the sides.

Since ( in theory ) the sound below 80 Hz that is produced by the sub is not localizable ( you can't tell where it is comming from ) it is better to determine the sub location based on its performance and interaction with your room.

It sounds like you have the makings for a great HT room.

 

[alias4cat]

more about crossover points and subs, please?

I will admit that I really don't understand the specs of crossover points. Can anyone give me a laypersons explanation? And is crossover frequency the same as "crossover points"?--the term used in my speaker manual?

My front towers are noted as having crossover points at 200Hz. I can't tell you what that means technically, but I can say that they reproduce lower tones to the extent that I am listening to a full range. That being said, I don't understand why I would want to put my sub in front with them when the back sat speakers have usable bass response at 60Hz and (again, while I don't know what that means technically), I "hear" that those speakers do not reproduce lower tones...instead as presently configured, lower tones are reproduced from the sub. I do not have the sub by itself in the back of the room; it is paired with two sats. The other two sats are in the middle, and the towers and middle channel are in the front.

From a audiophyte position, it would not appear sensible to put extra bass in the front at the loss of reducing it in the back. What I am aiming for is a room that gives good sound (muisic and video) effects throughout. The room is 24 foot long, and I generally sit in the back six feet.

Bottom line? Am I totally "off" in what I am attempting? Thanks again for all the advice and thoughts offered. I just got the RCA/sub cable and am aiming at connecting all speakers/sub today, so I can test the setup. Without some of your help, I might not even gotten this far (this stuff is way over my head).

--cat

 

[MDS]

In layman's terms the xover frequency is the frequency at which the signal is handed off from one driver to another. Search for 'crossover' (or xover) and 'slope' in the forums if you want a more technical explanation.

If your towers have a xover at 200 Hz, I assume it is a 3 way speaker. That would be the point at which the woofer stops playing and the mid-range driver takes over. There would also be a higher xover point between the mid-range and the tweeter - anywhere from 1 kHz to 3 kHz.

The xover frequencies you set in the receiver determines which part of the signal goes to the speaker and which part goes to the sub. That topic is involved too but you can read up on it by searching for 'bass management'.

 

[mulester7]

I will admit that I really don't understand the specs of crossover points. Can anyone give me a laypersons explanation? And is crossover frequency the same as "crossover points"?--the term used in my speaker manual?

My front towers are noted as having crossover points at 200Hz. I can't tell you what that means technically, but I can say that they reproduce lower tones to the extent that I am listening to a full range. That being said, I don't understand why I would want to put my sub in front with them when the back sat speakers have usable bass response at 60Hz and (again, while I don't know what that means technically), I "hear" that those speakers do not reproduce lower tones...instead as presently configured, lower tones are reproduced from the sub. I do not have the sub by itself in the back of the room; it is paired with two sats. The other two sats are in the middle, and the towers and middle channel are in the front.

From a audiophyte position, it would not appear sensible to put extra bass in the front at the loss of reducing it in the back. What I am aiming for is a room that gives good sound (muisic and video) effects throughout. The room is 24 foot long, and I generally sit in the back six feet.

Bottom line? Am I totally "off" in what I am attempting? Thanks again for all the advice and thoughts offered. I just got the RCA/sub cable and am aiming at connecting all speakers/sub today, so I can test the setup. Without some of your help, I might not even gotten this far (this stuff is way over my head).

--cat

.....very interesting thoughts, Alias....one question....with the soundstage across the front, why would one not want the mains going, I mean, to the floor?....LOW....there's always room for sub-extension.....all situations are different, Alias, good post.....

 

[mulester7]

In layman's terms the xover frequency is the frequency at which the signal is handed off from one driver to another. Search for 'crossover' (or xover) and 'slope' in the forums if you want a more technical explanation.

If your towers have a xover at 200 Hz, I assume it is a 3 way speaker. That would be the point at which the woofer stops playing and the mid-range driver takes over. There would also be a higher xover point between the mid-range and the tweeter - anywhere from 1 kHz to 3 kHz.

The xover frequencies you set in the receiver determines which part of the signal goes to the speaker and which part goes to the sub. That topic is involved too but you can read up on it by searching for 'bass management'.

.....aaahh, the three-way speaker....brings what's needed from only a pair being used by a die-hard stereo guy, but not the, I'm going to say, "modern", accomplishment....which is a two-way that speaks as one voice....now we're talking "realism transparency", and that, takes a hit with a three-way....three-way owners, don't lambast me, this is only based on what I've found with 2-ways, and plenty of experience with 3's....MDS, you only get better......