New sub - need some guidance

[sjtm]

I recently upgraded my integrated amp and, while shopping, came across a demo Focal SW800v subwoofer, which is the companion unit for my speakers. While it is rated only to 32hz @3db (27hz @6db), the price was right, the finish is an exact match to my speakers (WAF) and the seller was willing to let me return it if I do not like how it sounds.

My new amp manual (Marantz PM 11S3) does not specifically discuss hooking up a sub for a 2 cannel setup, although has multiple diagrams for multi-channel. There are left/right pre out rca jacks which I plan to use. Some questions:

I intend to place in the corner,which is about 8 feet away from the nearest speaker (speakers are about 7' apart), and about 13' from listening position. Should I position the speaker to fire straight out or pointed toward listener?

Speaker cable run is about 20'. I need RCA jacks at both ends. Anything special I should consider before buying cables?

My speakers (Focal 836v) are 3 way 8ohm rated down to 40hz @3db (33hz@6db). Crossovers are at 250hz/3000hz. When tested by Stereophile, these had a dip to 3.3ohms at around 110hz (one of the reasons I upgraded amp). Does any of this info give me insight as to where to set crossover for sub, or do I just go by ear?

I know this is not the lowest dynamic range sub available, but it does put my system into the dynamic range of the next step up in the Focal line (Electra 1038BE) for a tiny fraction of the cost, and I do not intend to use this for anything other than music. I am hopeful that this sub has the Focal sound that drew me to their speakers in the first place.

[sjtm]

My BJC subwoofer cables arrived. Also had tickets to my first concert of the fall (Lake Street Dive) and had a son needing to be picked up at the train at midnight. So I am just now listening to the new amp and subwoofer for the first time. As everyone is in bed, I decided to put on Nils Lofgren's "Acoustic Live". Love this album, but it has always sounded a little thin. Transformed! Not sure whether to attribute to sub or amp, but I have never enjoyed the full rich sound - even at very low listening levels. Will play with sub position at some point, but right now I am quite content.

[Mr Peabody]

With BJC you have a decent cable. You are correct that playing with position is necessary, no room or placement is usually the same.

You will have to use your ear some but if your mains play down to 40Hz flat I'd start the sub around 40Hz, if it's 40Hz at 3dB down you may want to start at 80Hz. I personally would not run the sub as high as 110. Your sub should blend as to not be able to hear where it's at in the room.

[blackraven]

I would try crossing over the sub at 45hz and go up from there. The sub should blend seamlessly. It should definitely not be heard with bass shy music. The problem that people run into with subs is that they set them too loud and too high a crossover point. I like to run my speakers full range with the sub crossed over about 5 to ten hz above the lower end of the frequency range of my speakers. It sounds the most natural. But a lot depends upon sub placement, your rooms acoustics, main speakers and personal preferences. I feel that if the sub is to high you may get exaggerated bass.

[sjtm]

For whatever reason, it has been pretty easy to blend in the subwoofer with the mains. I have done a bit of trial and error and somewhere between 60-80hz seems to sound right to me. Loving the enhancement it has given to my system.

Curious on your thoughts regarding 1 vs 2 subs. When properly dialed in, I have no real perception of sub's location in the soundstage - it just fills in the low frequencies without being directional. Yet I see many threads advocating for 2 subs, which seems to imply making them directional components in your system. My amp only has one set of pre-outs, so this is only hypothetical, but the 2 sub approach seems to be of marginal value at best, and possibly a contradiction to their basic design intent.

[Feanor]

For whatever reason, it has been pretty easy to blend in the subwoofer with the mains. I have done a bit of trial and error and somewhere between 60-80hz seems to sound right to me. Loving the enhancement it has given to my system.

Curious on your thoughts regarding 1 vs 2 subs. When properly dialed in, I have no real perception of sub's location in the soundstage - it just fills in the low frequencies without being directional. Yet I see many threads advocating for 2 subs, which seems to imply making them directional components in your system. My amp only has one set of pre-outs, so this is only hypothetical, but the 2 sub approach seems to be of marginal value at best, and possibly a contradiction to their basic design intent.

Generally it's considered that below 80 Hz sound is non-directional, thus is your crossover frequency is <= 80 Hz typically one subwoofer will do the job.

Since this is audio, opinions differ. One sound pro who used to hang out at AR said the two (or more) subwoofers offered more consistent bass sound throughout the listening area. Also of course two subs can deliver more output if that's an issue. If you have neither of these issues one sub should be fine.

[blackraven]

For whatever reason, it has been pretty easy to blend in the subwoofer with the mains. I have done a bit of trial and error and somewhere between 60-80hz seems to sound right to me. Loving the enhancement it has given to my system.

Curious on your thoughts regarding 1 vs 2 subs. When properly dialed in, I have no real perception of sub's location in the soundstage - it just fills in the low frequencies without being directional. Yet I see many threads advocating for 2 subs, which seems to imply making them directional components in your system. My amp only has one set of pre-outs, so this is only hypothetical, but the 2 sub approach seems to be of marginal value at best, and possibly a contradiction to their basic design intent.

I went to 2 subs several months ago and I am glad I did. The sound stage became wider and deeper. The 2 subs lend a fullness to the music better than 1 sub. It is not a dramatic change but it is very noticeable. My room is 17x17. I am going to have a friend come over and analyze the bass to dial them in.

I have a friend that has a Rhythmik sub and just added a second and his experience shadows mine. His room is much smaller than mine and uses the subs in a near field set up with Magnepan 1.7 speakers.

Larry

[sjtm]

Generally it's considered that below 80 Hz sound is non-directional, thus is your crossover frequency is <= 80 Hz typically one subwoofer will do the job.

Since this is audio, opinions differ. One sound pro who used to hang out at AR said the two (or more) subwoofers offered more consistent bass sound throughout the listening area. Also of course two subs can deliver more output if that's an issue. If you have neither of these issues one sub should be fine.

According to Focal spec sheet, the initial crossover is at 250hz. What effect does that have on selection of appropriate crossover setting for the sub?

[Mr Peabody]

The 250Hz is where Focal crosses the bass driver from the midrange, this has nothing to do with how you set your sub. You want to look at the speaker's frequency response to see where the low end extends to and how many dB down, it will say +/- so many dB.

The 836v looks to be 40Hz at 3dB down, so run the sub's crossover between 40 & 80Hz to see where it blends best. I think anything above 80Hz would cause too much overlap and not blend well.