Setting mains to large with cheap sub (1 Viewer)

[Richard_M]

I am using B&W 603S2 for mains which are good to 48 Hz approx. The mains & centre are being driven by a Rotel power amp so power is not an issue. I have been offered a Yamaha YST-305 Subwoofer cheap and was wondering if hanging it off my mains and making them large would be a good move.

I find that if I set my mains to large music sounds more natural especially Eric Clapton guitar playing. Currently all speakers set to small 80 Hz xover Denon 3802

The Yamaha sub should be good to 30 Hz. I was thinking cross over sub at 50 Hz and run test sweep 2 Hz steps (.1 subs off) from say 30 - 100 Hz to try and match sub to the mains

Is 30 Hz enough for main speakers, and would the Yamaha sub be able to keep up to ref levels? Not that I usually listen at ref levels.

Also would the new sub react with my .1 subs as far as cancellations and peaks are concerned?

Thanks

Richard

 

[Wayne A. Pflughaupt]

Richard,
Your post is a little confusing, but I take it you want to extend the response of your front B&Ws, and you wonder if that will conflict with your current sub (which you gave us no information on)?

Also would the new sub react with my .1 subs as far as cancellations and peaks are concerned?

Anytime you have low frequencies emanating from multiple sources, you can expect cancellation and phase issues to appear.
Regards,
Wayne A. Pflughaupt

 

[Richard_M]

Thanks for the reply Wayne,

Sorry if I was a bit confusing, with my question.

My main Subs are 1xM&K 5000 MKII & 2x M&K V-125's which I have blended in and are using a BFD (1x channel for the 5000 & 1x channel for the other two)to tame the peaks.

I find if I make my mains large that the guitars sound more natural to my ears, but of course the mains only go to 48hz, hence my inquiry. You are correct in that I am trying to extend the range of my main speakers.

My room has a dip from approx 50hz ~ 60hz, I think this is where the problem where the subs are concerned, I have run a freq sweep from the mains and they don't appear to have this dip. I think this is why the guitars don't sound as natural. The current room layout does not allow for much movement(placement)of the subs, (this will be rectified when we move later this year)

Regards,

Richard

 

[Richard_M]

Just an update,

I have borrowed the Yamaha sub and have hung it off my main speakers. crossover on sub set to ~50hz.

I am running the mains on small i.e xover is 80hz on receiver, and the sub filling in the bottom end nicely.

I have virtually eliminated the ~50-60hz dip, but what amazes me is how much information is being sent to the speakers below the xover frequency.

This has made the guitars sound more natural, which is what I have been trying to achieve.

Now I am wondering if I should have all my speakers xover set to 100hz, there must be alot of material that the centre and surrounds are unable to produce, due to the -3db point being ~50-60hz, and let my subs get these extra frequencies.

Any thoughts?

Richard

 

[DaveVan]

Question from a newbie:
If your mains handle well down to 48Hz, why would you cut them off by setting them to small?

 

[Steve_Ma]

Richard,
For what it's worth, I keep my 603s as well as my center and surrounds crossed over at 100hz. My speakers and room simply give a better (flatter) response when they are crossed over at 100hz as opposed to any lower points.
Dave,
Setting even decent towers to small makes sense almost any time you have a subwoofer to augment the low end performance. Consider that crossovers are sloping by their nature. They are not brick walls. For speakers and subwoofers to work well together they must be capable of handling material well above and well below the crossover points. A quick experiment to demonstrate what I'm talking about: Disconnect your sub, but keep the settings the same. Now, play some test tones starting at about 120hz and go down to about 50hz. What you'll see is that the main speakers are still producing bits and pices of sound well below the crossover point. You're question is a good one, however and it cuts right to the heart of the "Bookshelf vs Tower" debate. Here's a good article on this issue:
http://www.hometheaterhifi.com/volum...rs-9-2002.html
--steve

 

[DaveVan]

I see now, thank you

 

[Richard_M]

Thanks Steve, for the reply and informative link.
I will give it a test next weekend when I am home by myself, the wife just loves those freq sweeps
Richard