Theoretically speaking this will increase the output of the speaker below the baffle step frequency (defined by the width of the speaker baffle – http://sound.westhost.com/bafflestep.htm). What a great summary of a straight-forward way to make sure you have enough power for your speakers. http://www.audioholics.com/audio-amplifier/the-all-channels-driven-amplifier-test-controversy. I agree that your spreadsheet is an excellent tool for spec’ing out an AVR/speaker combo. I’d love to one day! It is used by us in both commercial and home theater. I ran across your calculator while researching AV Receiver specs for a potential upgrade. The Denon was purchased to drive an existing set of Klipsch surround speakers and its 130 watt per channel rating met the simple rule of thumb I had read somewhere at the time – make sure the receiver’s output rating was (at least) 50% higher than the max continuous rating of the speakers it is driving. I’m just using this for my HT setup in my family room. Peaks in movie soundtracks can therefore reach 105dB (0dB relative to ful… 1. Find Out what Acoustic Frontiers can do for you, July 25, 2013 26 Comments | Leave a Comment. If the tweeter is the limiting factor then no it won’t increase output potential. The approach to calculating amplifier power requirements for THX reference level reproduction presented above is of course a simplification. Reference level for all channels except low frequency effects is calibrated by adjusting the audio chain such that a pink noise signal recorded at -20dB relative to full scale creates 85dB SPL as measured with a C weighted meter at the primary seating location. What is ‘THX Reference Level’? 15360x8640 (16K UHD), Diagonal Screen Size: Most (but not all) speakers are SPL limited by the bass drivers. I wanted to use your tool to see if I was providing adequate power to them. The distance is equal to the point at which not all of a picture's details can be resolved, i.e. The reference level requirement is 105dB peaks. Thanks so much for this calculator. inches Dolby Atmos – the hottest format, that has conquered the world of both commercial and home cinema and entertainment electronics. The answer to the question depends on a few things, in particular how sensitive your speakers are and how far you sit away from them. Also, I am not running the mains as "Large", so shouldn't we get additional headroom if we cut them off at say 80 Hz? Amplifiers with very robust power supplies tend to have low dynamic headroom and those with weaker power supplies such as your typical AV receiver high dynamic headroom. The output wattage of AVRs may be spec sheet 105W per channel but in reality it will be less than that with two or five channels driven. Thank you so much! User instructions: Choose your TV/monitor's resolution from the available list of standard sizes, or input your own manually For a system of 5 speakers with frequency routing Subwoofers there will be required a power of 6 more decibels and for a system of 7 speakers 8 more decibels in addition to the initial 115 decibels. Note in 1) the output is specified into “half space” (in a test baffle which would have been shaped and cut around the baffle…kind of making the speaker an infinite baffle…that is how a lot of companies measure peak output) which provides a 6dB boost over “free space” (out into the room) mounting. If the calculator shows a value of 137 RMS watts, then that’s the power rating your AVR would need to have to deliver THX reference level with the parameters you entered. The only real way to know would be to measure each system individually using some kind of test signal and monitor speaker distortion or other parameters. Keep reading. For music I have seen written that during mixing engineers will use anywhere from 70-90dB SPL! 720x576 (DV PAL) The 6dB assumes free space. A question that frequently comes up when designing a home theater is ‘how powerful an amplifier do I need?’. Thank you so much for the article, it is fantastic. 20 A well-designed room that will make you forget about the outside world for long hours and disconnect from everyday thoughts, sounds good to you? If you have the formulas used on the amplifier Power calculator, could be great to know them. for use in every day domestic and commercial use! Here are my questions: Hi. SPL required is already known – we want 105dB peaks at the listening position to meet specifications. Even just an idea would be helpful. Many people also make a simple mistake which effectively doubles the size of amplifier required. Maybe that’s just my ignorance on how impedance affects power ratings. 960x540 (qHD) I’m assuming that since the 137 watt calculator result equates to the peak sound pressure of 105 Db, the speakers can handle the 137 watt power draw if it only occurs only in short bursts – is that correct? 10 This power will ensure that the balance is maintained, all platforms and scales will be able to enjoy the true director’s direction, while editing the soundtrack. When I run your calculator with my specific parameters the results are an RMS power requirement of 137 watts. 640x480 (NTSC) Thank you. 200. I was poking around your site and noticed you updated your SPL calculator with some of the items we talked about last year. When visual acuity is lower than 20/20, the value should be reduced, or increased if visual acuity is higher than 20/20. They make the mistake of equating peak SPL with RMS Watts. I have found your article the best I have seen on the subject. A sine wave has a 3dB crest factor i.e. On every THX Certified AV Receiver the “0” on the volume dial represents THX Reference Level, the exact volume level used by the moviemakers and sound artists in the studio. I’m thinking this would be another line item in the SPL calculations. Private screening room – the real thing in your home, 5 reasons that will make you want a cinema system in your home. 30 I have 4 Optima 250 power amps rated at 125 per channel. Keep reading, A high-quality home theater system, one that is very carefully designed and activated by the press of a button, is without a doubt one of the most exciting things in your home. If you really want to experience the “poet’s intention” at the most faithful level, you will need a system that knows how to meet these powers, without distortions, without compression, over time and in a reliable way. Thanks! If it’s the woofer then yes it will increase output potential. Screen Height: And what’s all the buzz about? One of things I am struggling with is how can I determine or get a feel for whether or not my current system can be played at reference levels (or close to reference levels) safely or without clipping and distortion. I have a Denon AVR x3000 and am using Polk Audio RTiA3 speakers as mains. 1440x1080 (HDV 1080) We have prepared for you a short and concise article that will help you understand what all the fuss is about …, Thx Baffle Wall is actually a “false” wall and one of the cornerstones of a movie theater in the Thx Certification. Is it possible for the genelec 8050b to hit reference level playback without compression at 3-4 meters from speakers?