I just received mt new speakers for the HT room - Marantz SS2500. I have a Sony STR-DE598 reciever. How should I connect the sub up to the receiver?
I have been researching a little - the sub is passive so should I make a cable to connect the sub to the sub output (RCA type connector on receiver to banana post on sub) or wire it into another channel on the speakers for the surround?

If the sub is passive then you need an amplifier between the receiver and the sub. The RCA connector on your receiver is the signal that feeds the plate amp which in turn powers the sub. You can not hook up the RCA sub out from the receiver to the banana post on the sub. PartsExpress.com is one place that sells good quailty plate amps at a fair price.
http://www.partsexpress.com/webpage.cfm?we...ectGroup_ID=505

doesn't this imply I don't need an amp?
http://www.techlore.com/article/11131/?page=1

Hopefully your Sony receiver won't trip the circuit protection or blow a fuse. The Sony receiver was designed for an external amp to power the sub. It's up to you whether you want to try hooking it up differently then what is recommended by the manufacturer. Let us know how it turns out.

I don't want to blow anything up! What specifically should I look for in the amp? I am searching on the website yo recommended and ebay and there are a lot to choose from.

I can't find any specs for that system, but I'll guess those speakers are 6 ohms since that is what the reciever that goes with that sysytem puts out.

http://us.marantz.com/ER2500S_SPECS.pdf

A plate amp with 150 watts into 4 ohms would be lots of power for that sub. Just go easy on it. It doesn't take much for those little subs to bottom out.

A passive sub does not need power from a seperate amp. Unless the definition of passive subwoofer has changed, the power fro the sub comes from the main front channels and the the sub has a built in crossover to which the smaller satellite speakers are attached. This product would have been more accurately sold as an "unpowered sub". Take a look at this picture:



You can see the power takeoffs and the connections for each individual speaker. That combined with the writeup about the piece having "7 Discrete amps" makes me believe that the crossover network for this unit is inside the unit, not on the sub.

MikeyP is correct in saying that you will need an amp since I dont think that Sony has a dedicated amp circuit for subs. You may not have saved as much as you thought you had.

The good news is that any cheap amp will run the sub after you feed it the sub out from the Sony...

BTW. Partsexpress is a very fair company to deal with...You cant go wrong with them.

SJ

You are right. A passive sub has a built in crossover as shown in the connection diagram here.
http://www.klhaudio.com/hookuphtpassive.htm
The Marantz sub only has bannana jack connection making it a "unpowered sub"

Passive speakers are usually a pair of speakers in a single enclosure. Instead of in a ported system with a speaker and an air port there is another speaker instead. One is powered and the other is passive and moves by the air pressure exerted by the powered speaker, acting as a port.

That’s called a passive radiator.

DJ

AndeeW,

First off there is a difference between a sub that is an active sub with a passive radiator and a passively driven (no amp) sub.

You need to find out what you have. The problem with a passive(no amp) type of sub is that the crossover may not be properly designed to work with the front speakers. And even worse, most modern AV receivers have protection circuits in them to make sure you don't hook up some 4 or 5 ohm or lower, loads to any of the speaker outputs. IF the crossover has not been properly designed to integrate with the front speakers you could end up with a 4 ohm load or less on the front two channels and the AV receivers protection circuitry will kick in.

There is a reason for this protection circuitry. The power supply of a consumer grade AV receiver is asked to do a lot to drive 7 channels. It is too much current drain to have low impeadance loads on any of the channels. ALso, since current is generally in short supply in a AV receiver the last thing you want to do is use the receivers amps to power a sub in addition to all the other channels.

I would get a sub amp. You could also use an old surplus receiver to drive the sub. It will sound better anyway by not robbing current from the other main channels of the system.

That diagram states that you have to set the left and right channels to "large" (that sends bass to the left and right channels), and the receiver's subwoofer setting to "off" (turning off the lfe? port). "Failure to do so will result in little or no bass".

I think you can leave the subwoofer setting to "on". The bass is already being sent to the left and right channels. I'm going to set up my system this way (hopefully being able to use the built in crossover in my old pair of DCM KX12 Series 1), and I want to be able to add Aura Bass Shakers through the subwoofer output.