Axiom Home Page Forums General Discussion Stereo Crossover setting for a Sub

I recently purchased a REL sub Q150E to go with my 2 channel Rotel/Axiom system (see below my system). I use High-pass level connection in my sub, but I don't seem to set the crossover in the sub right. I initially thought it sounded right around 40 MHZ but then I moved it up to around 60 and sounded kind of better. What do you guys do with your Axiom floorstanders. Any suggestions??

Rule of thumb is set crossover at 80. Some go to 60. Try both and see what sounds and works best. I have 60s with a SVS PB12 sub and I have my mains at small and crossed at 80.

I use 80 with all speakers set to small.

The ear test is best but for rules of thumbs there are two main ones.

1. Set the crossover between 1/2 octave to a full octave above the minimum frequency response of the mains. So a speaker with a 40hz FR would be crossed at 60hz to 80 hz.

2. Set the crossover to 2 times the FR. ( Same as one octave up). 40hz speaker gets crossed at 80hz.

The instruction manual of my ICMB recommends to add 10Hz to the +/- 3 DB point of the speaker. If you go by that try 50 Hz on the subs crossover. I have my 80s set to 60 Hz, there is no 50Hz setting on the ICMB or that would have been what I would have chosen.

Thank you guys for the advice! It is great to hear what the other Axiom owners do with their Axiom floorstanders. I never owned a sub before - if you don't count here the sub that came with my HTIB or PC sub.

I now realize that I was wrong in the first place when I set it up at 40, thinking that the sub will cover the lower frequencies not covered by the floorstanders. I am gonna try setting it at 60 and 80 this evening when I get back from work.
I have placed it close to the corner of the room, behind the right spekaer, with the woofer facing out and towards listening position. Is that the usual pattern? I tried it in different places, even by the left speaker.

As for setting the mains at "small" or "large", I cannot do that since I do not have a multichannel receiver/processor with such setting. I have a 2 channel processor/power amp combo (please see below).

Placement depends on your room, and where it sounds best to you. Many have recommended the crawl test: place the subwoofer in your primary listening position, and play a CD with tons of bass, and then crawl around the room. The area where the bass sounds the best, is where you should place your subwoofer.

How do you have your subwoofer hooked up right now?

I use the high-pass connection on my sub, which is a bit different than the usual high level connection: they have a special cable that gets connected to the main amp, right where the speakers gets connected, in order to receive full signal from the amplifier.

Jinhan, do you mean I should place the sub close to the sofa where I sit (sweet spot) and move around the room until I find the best sounding place?

I finally got an email from REL distributor in USA to reply to my inquiry (see below). Do they suggest I cross it over at around 25 HZ, or I read it wrong??!!!

In reply to:

---

Hello,

Thank you for your interest in REL. The best thing to do is to follow the four-step setup procedure outlined on our website, listed below, under REL / Owner's Manuals / REL Setup guide. This will get you to the right position and at the right settings. There is no "right answer" since room acoustics will affect the position of the controls. However, a good guess, based on a lot of experience, is that the crossover will be somewhere in the mid to high 20 Hz range, as the REL will play above the crossover point as well as below.

Sincerely,

---

Basically, the website instruction, as well as REL manual let you set it up with ear and NO recommendations on numbers are made at all.

Yes, Skerdi, that's what they're suggesting. I hesitated in replying here because I've read the REL literature and simply didn't accept their rationale. They urge using the sub to just reinforce the very bottom of the bass range, but my thought is to disregard their advice and use the line level connection(rather than their special high level connection)and set a crossover somewhere in the 60-80Hz area in the receiver, setting the REL crossover to bypass.