Sunday, February 25, 2018

Home theatre not rumbling enough? Here are some ways to tweak your system

By Jim Bray

You've shelled out good, after tax disposable income on a home theatre setup but instead of that room-rattling bass you've been promised you're only getting a thin gruel oozing its way to your ears. Did you get ripped off?

That's always a possibility, but even an inexpensive "home theatre in a box" can deliver good, room filling sound with chest thumping low frequency effects, so before you box it up again and toss it back across the counter at the retailer from whom you purchased it, take a while to do some tweaking to ensure it's performing to the best of its capabilities.

It's best do this during your grace period - the time the retailer allows you to change your mind - otherwise you may be stuck with equipment you don't like, though you may be able to make some friends on places like eBay, Kijiji, etc..

In my work, I often swap out components and try new ones, so I'm always messing with the various parameters, searching for the white whale of perfect sound. Sometimes no tweaking is necessary, often it is - and sometimes I never do get it right but manage to get it close enough to be highly enjoyable anyway. And sometimes I just throw my hands up in frustration (fortunately, this is rare!).

I’ve even installed sound deadening material in my "big" home theatre, hoping to make everything perfect, and it helped a lot, but I can’t imagine getting the sound absolutely perfect unless I build a room from scratch or spend a lot more money than I’d be allowed to by my highly significant other.

Even equipment you've had for a while can change sonically depending on circumstances. I had a flood in my home theatre a couple of years ago that forced me to move all the electronics out, and I'm still  tweaking (thanks to being reasonably anal about it) to ensure the best sound.  

Worse, my smaller home theatre seems to have developed an issue in which the bass leaves something to be desired during stereo playback, while surround stuff will practically peel paint from the walls. It's quite frustrating, though it does encourage me to stick with my surround albums as much as possible…

Bass basics…

It appears I'm not alone in audio angst: I got an email from a reader recently who complained his/her/its bass was too boomy, and wondered whether, since I'd mentioned using 100 Hz as a crossover point in one of my reviews, changing his/her/its crossover point would make a difference.

Crossover is the frequency at which the high frequency sounds are split from the low frequency ones, directing them to the woofer or subwoofer. He was running at 80 Hertz, which is default for many systems, and wondered if he should change to the one I was using.

It was a question I couldn't answer to my satisfaction (and probably his/hers/its!) because I don't know his/her/its room, and I'm not familiar with his/her/its equipment - though from the email it sounds like he/she/it has pretty good stuff.

Since I couldn't answer that specific question for this particular individual, I merely gave some generic tips, which I now pass along to you in case you're having similar issues.
There are many reasons why your bass could be too boomy and it can be as much an art as a science getting this done properly unless you're willing to spend big bucks for professional help, or for an audio system that "self-corrects." So there will always be compromises. The idea is to get the best you can under the circumstances.

The first thing you should do is write down the settings you're using currently, assuming you're not running the stuff the way it came out of the box. This is very important because you may do quite a bit of tweaking and, if you're anything like me, you'll sometimes screw it up so badly you'll want to go back to the beginning and start over. If you don't have your current parameters recorded, you could be out of luck.

Start with the defaults recommended by the equipment makers. If you need tweaks to reduce the bass, it could be as simple a task as moving your subwoofer away from the wall or corner and into the room a bit more. You could also look on the back of the subwoofer and see if it has a phase switch or crossover adjustments. A speaker out of phase will sound "hollow" and unrealistic, so if that's your issue try that first, by ensuring where possible that you have positive terminals hooked to positive and negative to negative.

This applies to all speakers, not just the sub. On the other hand, a powered subwoofer often only has one cable to connect it to the preamp, so you can't swap positive and negative wires. Hence the phase switch.

This doesn't always work. I had a system once where it sounded best if I kept one speaker out of phase, so use this advice (and everything else I say) as merely a rule of thumb.

In my big home theatre installation I use 100 Hz as the crossover because my ears tell me it sounds best that way - whereas in my smaller installation upstairs I prefer 80 Hz, because it works best there. It probably doesn't help for consistency that my big theatre room is laid out "portrait" while the smaller one is "landscape."

That's right: the room itself is a huge influence on this!

Your receiver/preamp/processor may also have tone adjustments built in. I try to run everything flat, for consistency if nothing else (for apples-to-apples audio equipment comparisons) but sometimes a tweak is necessary and that's not necessarily bad.

Depending on your equipment you could have oodles of adjustments, or very few. Use what you have, and don't be afraid to try different settings. If you've written down your starting settings you can experiment to your heart's content and you won't hurt anything (probably…).

Don't just tweak and tweak away with wild abandon, though. Try different settings and leave them for a long enough period that you can get a real feel for the changes (it doesn't hurt if you write down all the tweaks you make as well, because you may want to go back later to a particular one).

I did this last weekend, messing with the smaller theatre to try getting that stereo bass issue solved. And I have made improvements, though it isn't yet where I want it. But since I've kept notes I can go back any time and even if I screw things up I can go back. In the meantime, I'm giving it a few days of listening without more tweaking to ensure a fair test of its current configuration.

You might also want to try a sound pressure level meter, or get a sound pressure level app for your smart device. These let you balance the individual speakers' volumes so they all play at the same level, and it can give you a huge leg up on getting the best sound. Set your system (assuming you have this feature - and you might be surprised to find what's in your system's menus) so the loudest speaker is set to zero decibels, and then "down tweak" the rest of the speakers to the same sound pressure level from there. Be aware, though, that when it comes to a subwoofer's level settings, your sound meter may flutter quite a bit and it's hard to get a constant reading as bass interacts with your room. Try to find a happy medium.

You can always tweak the bass output setting a smidgeon here and there. Again, the key is to listen for an extended period to find that sweet setting.

You can, and should, also set your speaker distances. This usually requires a second person, one to hold the tape measure and one to monitor the SPL meter. This can make up for speakers that aren't necessarily all the same distance from your ears, and it can make a huge difference.

Alas, there's no hard and fast rule that "if you do A your sound will be perfect," so do your own tweaking and settle on the settings that create the sound that's best to you. It's your stuff, your ears, and your money, so the bottom line is that you - not me or anyone else - has to be happy with it.

Good luck, and happy viewing/listening!

Copyright 2018 Jim Bray

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