How Much is Enough?

How Much is Enough?

by Frank White with Anthony Grimani

Our latest for Grimani Systems, this comes from our list of the top 50 recurring problems in home theater systems - gathered over the last 25 years from more than 1,000 high-performance installation projects.

What the devil is this "headroom?"

You don't hear the term "headroom" in our industry much. Check out this case study:

Worked in a machine shop as project manager in the late 70s trying to fund our fledgling AV company. Had about 15 detail machinists, 10 welders, and 6 assemblers, all using pneumatic tools. The compressor was driven by an old '68 GM 350 2bbl delivering a realistic 170 or so horsepower.  That motor was well over a decade old and was run for 15 hours a day, 6 days a week. No one was ever short on air power. The 60 year old facilities guy kept the oil, coolant, and plugs changed and topped. That motor was run well under its capabilities - we call that "headroom". The objective of reliability was met. Heard from an old buddy... that motor lasted another 14 years.

To restate: The engine had much more capability than required. That is headroom.

How does headroom fit in today's problem? Let's unwrap this a bit. A great starting question would be: Do you have any idea how much amplifier power and cone area it really takes to drive sub-sonic frequencies in your client's theater room? Also, how do you know?

As your engineering DNA start to kick in, terms like total room volume, room dimensions, surfaces, reflections, resonances, seating placements, acoustic room isolation, and budget all compete for their proper prioritization in your design.

As Anthony Grimani tells it, he always brings a gun to a knife fight, so to speak. When it comes to subwoofer capability, he's most comfortable specifying more amp and speaker than most would think is necessary. 

When you default to that standard subwoofer that you've used 100 times in the past, you're under-addressing this point and missing out on what really sets you and your client's home theater apart. Furthermore, you're potentially missing out on a truly great opportunity to immerse listeners in the wonder, amazement, and magic that is delivered by music and great cinematic art. Not to mention word of mouth recommendations that come with a great experience!

At its basic core, it's simple. It takes at least 110 dB of clean and tight bass in a home theater to get listeners to crack a smile. True reference level requires 115 dB for LFE alone. Targeting 115-118 dB gives you sufficient headroom so that your subwoofers aren't straining or limiting at 110 dB. Many home theaters have plainly anemic bass that tops out at 90 dB at the needed frequencies - barely enough to get any reaction at all from the audience. Of course, it takes subwoofers that are powerful enough. Subs that appear on the surface to be similar can differ in bass delivery by a full 10 dB! Also, proper tuning can make huge differences. Properly setting the delay for the back pair of subwoofers in a four subwoofer configuration can eek out 12 dB of additional bass in the bottom octave just like that. You do need an outboard digital equalizer to make it all happen - but talk about a huge bang for the buck!

So here's our solution set: It takes horsepower and tuning to achieve sufficient bass headroom. You need enough cone area, enough amplifier power, and multiple subwoofers that are placed for maximized room gain efficiency. Then you need to carefully tune the relative delays, EQs, and levels of the subs until you squeeze out every little ounce of sound pressure from 20 Hz to 100 Hz. This cannot be done without the right spectrum analyzer, the right test signals, the right engineering talent, the right subwoofers, and the right amount of time to make it all happen.

While on the web, check out Anthony's new offerings at Grimani Systems.

Thanks for investing a few with us on this topic. We look forward to your success!

To ge hold for Frank, (I build compelling narrative around your message) - [email protected] 

Steve Colburn

High end home theater design/build consultation.

8 年

Great article, Frank! At Triad, we've been beating the Timpani for a long while on the benefits of multiple subs, properly positioned & tuned. The good news is that we are getting traction; many more home theaters are being installed with good bass all over. A lesser known secret is that properly pressurizing a room with bass improves its sound at lower levels as well as high - so listeners benefit all the time.

John Balboni

Sound Advice & Sight & Sound Service, Veteran.

8 年

Thanks, this is great!

要查看或添加评论,请登录

Frank White Creative Content, Biz Development的更多文章

  • Tumbleweed Client Syndrome

    Tumbleweed Client Syndrome

    Frank White, Rookie Storyteller March 2021 · Shared with Public 800 words, average collage qualified reader clocks in…

    2 条评论
  • Maintenance Needed, Will Revenue Follow?

    Maintenance Needed, Will Revenue Follow?

    By Frank White Critical discussions regarding system maintenance and recurring revenue. 900 or so words, a 4 min rabbit…

  • Bill Gates: "Life's Not Fair, Get Used It"

    Bill Gates: "Life's Not Fair, Get Used It"

    Nope - Not Fair. No one ever promised other wise.

    1 条评论
  • Yesterdays Success Doesn't Pay Tomorrows Tolls

    Yesterdays Success Doesn't Pay Tomorrows Tolls

    The Endless Rat-wheel of CI Economics By Frank White, WELD2 A month or so back the stock market hit a minor speed-bump.…

  • I Was Being An Ass

    I Was Being An Ass

    +/- 1100 words, 4.5 min read.

    2 条评论
  • Automating customer relationships....

    Automating customer relationships....

    We all have relationships, if you are an industry insider, company owner, have a sales role, manage or interact with…

  • Relentless Change And The Pressure To Scale:

    Relentless Change And The Pressure To Scale:

    By Frank White Weld2 Partner The year was 1967, “All You Need Is Love, & Penny Lane” dominated the charts. This member…

  • Every Seat is Important:

    Every Seat is Important:

    Bad Vertical Coverage of Line Array Speakers Toward the Bottom Where People Sit: The Sound is Dull, Missing Midrange…

    3 条评论
  • The Labor Plague & New Credible Slant

    The Labor Plague & New Credible Slant

    We’ve put out around 40 of these articles over the last year or so and hope you have found value in them. Now for…

  • Are You A Snob?

    Are You A Snob?

    By Frank White, Weld2 partner Had a kitchen guy come by and talk with us about upgrading a few things, some cabs and…

    11 条评论

社区洞察

其他会员也浏览了