Behringer’s ECM-8000 mike, a USB preamp, and True RTA software are all you need to perfect your system’s bass
Behringer’s ECM-8000 mike, a USB preamp, and True RTA software are all you need to perfect your system’s bass
In order to get the transition between your subwoofer and your main speakers close to perfect, you need measurement gear. Measurement makes your sub setup faster and more accurate. Instead of listening to bass lines to gauge the evenness of your bass response, you just run a quick measurement and get a precise result.
The process is simple. Use audio-spectrum-analyzer software that runs on your computer or smartphone. Set up a test microphone (or hold your smartphone) in your listening position. Play the appropriate test tone and you’ll see the level of each frequency of sound onscreen.
The idea is to get each bass frequency at roughly the same level. Run the test, then adjust your subwoofer position, crossover frequency, etc., and then run the test again. Repeat until you get the flattest response.
Since I last wrote about audio measurement, I’ve been evaluating some analyzers that weren’t in the original article. One is Room EQ Wizard, a Windows PC application available free from hometheatershack.com. REW combines several functions, including a sweep analyzer that measures your system response with a swept bass tone. You’ll need a microphone to use with it; you can use the popular Behringer ECM-8000 with a USB mike pre, or connect the output jack of an SPL meter straight into your computer.
You can also get spectrum-analysis apps for your smartphone. To measure subs, you need an app with at least 1/6th-octave resolution. For the iPhone, there's Studio Six Digital's AudioTools, while my favorite Android apps are AudioTool ($6.50) and RTA Pro ($5.68). AudioTool is more versatile; it includes a signal generator. With RTA Pro, you’ll have to play pink noise through your system to run a measurement. If you don’t have pink noise on a test disc somewhere, it (along with other tones) is available free at brentbutterworth.com/tech.
There are also a couple of room measurement packages in a box that come with the hardware (microphone, sound card, cabling) such as Dayton Audio Omnimic and XTZ Room Analyzer.
With these tools available I am not sure why anyone would try to tune their system by ear, or integrate a sub! You should note that quite often the automated set algorithms in the AVRs do a poor job of things! Though they do seem to be getting better slowly
A good practical article, with one notable exception. I thought the goal of setting up a subwoofer, or other speakers for that matter, is to set them up to make the music played back in the room as accurate as possible relative to what the recording engineer intended when they mastered the recording you play. I understand the vast majority of recording engineers anticipate playback in rooms that boost low frequencies and attenuate high frequencies, so they equalize recordings with attenuated low frequencies and boosted high frequencies. Thus, to get the recording engineers' intended sound, we need to adjust our setups such that they boost low frequencies and attenuate high frequencies.
I think it would be helpful if the authors addressed this either to correct my misunderstanding if I'm mistaken, or clarify that we shouldn't really shoot for a flat response with test signals. Thanks for a great publication that cuts through the mumbo-jumbo of so many other audio and video publications!
Please look at post #25 at http://www.diyaudio.com/forums/pc-based/181527-anyone-using-drc-3.html for what I mean in using a target curve with test signals that is not flat. Many use what is called the "B&K house curve" as referenced in the post, and available in the link that is inside the post.
What do you think of using such a curve instead of a flat target curve? Thanks for any insight!
Hi, candycane. I think it's probably impossible to make any assumption about what kind of assumptions the engineers made about what kind of room the material would be heard in. In movie sound, it used to be safe to assume the material was mixed for a movie theater (the well-known X-curve and the genesis of THX Re-EQ). But since the DVD era, it's become common to re-mix movie soundtracks for the home environment. For example, a while back, I visited MiCasa Studios in L.A. (where the James Bond re-issues, as well as many other DVD/Blu-ray projects were produced), and their main mixing room is an actual living room in a house.
And with music, it's all over the map. I've been in countless music recording studios and seen all sorts of subwoofer setups.
So if one EQ curve sounds good for you, IMHO that's the one you should go with. Your ability to "hear what the engineer heard" is very limited in any situation because your room, system, and setup will be radically different. And it's especially so in the bass, where the effects of room acoustics are colossal.
Personally, I like to EQ my system so it's close to flat, although I don't get too nuts about EQ-ing out the 40 Hz bump I get from my lowest axial mode. Sometimes when you go too heavy on the EQ it seems to take some of the kick out of the sound. A totally subjective perspective, yes, but several manufacturers who've set up their gear in my home came to the same conclusion.