{"product":{"product_id":"113892136X","title":"Sound Reproduction: The Acoustics and Psychoacoustics of Loudspeakers and Rooms (Audio Engineering Society Presents)","price":"52.46","image_url":"https://m.media-amazon.com/images/I/519JOOcSKpL._SL500_.jpg","url":"https://www.amazon.com/dp/113892136X"},"comments":[{"body":"Sort of. You're combining at least three separate concepts. \r\n\r\n1) **Speaker Boundary Interference (SBIR)** - above a frequency proportional to the distance to the rear wall, the reflection will interfere with the direct sound. Shorter distances affect higher frequencies that tend  to be more directional and not seen by the wall anyways.\r\n\r\n2) **Boundary gain** - below a frequency, the rear wall reinforces (~+6dB) the bass response of the speaker. This can be shelved down in DSP to mitigate. The owner of the system pictured does so.\r\n\r\n3) **Port vent** - the tuned port extends the response of the system but a wall won't affect it that much. The rule of thumb is a distance of 1-2x the port diameter from the wall to not change the port performance.\r\n\r\nThe reason why ports and wall placement often come up together is because boundary gain can be offset by plugging the port.\r\n\r\nAlso, this system belongs to Dr. Floyd Toole who was the VP of research for Harman. They [literally wrote the book on sound reproduction](https://www.amazon.com/Sound-Reproduction-Acoustics-Psychoacoustics-Loudspeakers/dp/113892136X).\r\n\r\nIs the placement ideal? Not really. Does Reddit know better? Not really.\r\n\r\nIn their book, they describe a few of the steps that they took to mitigate some of the problems that I listed above. Maintaining livable space was more important than the small hifi improvements.","subreddit_name":"audiophile","author":"Umlautica"},{"body":"\u0026gt; My own interpretation of the data probably won't be very good at this point, but if his stuff is consistent, it'll hopefully be a useful source to learn from.\r\n\r\nFor really learning about speakers, I'd refer you to [this book](https://www.amazon.com/Sound-Reproduction-Psychoacoustics-Loudspeakers-Engineering/dp/113892136X/ref=pd_lpo_1?pd_rd_i=113892136X\u0026amp;psc=1) as it's based on research by Floyd Toole.  For those that value objective measurements his research is effectively the gospel as he basically built the standard at NRC and Harman.\r\n\r\nOther than that there's a lot of independent research one can do.  Reading back into Sean Olive's blog (picked up Floyd's torch), and videos/presentations by them and Andrew Jones (leans engineering oriented).\r\n\r\nThose are going to be some of the loudest voices when it comes to measurements, their usefulness, shortcomings if applicable, etc.","subreddit_name":"audiophile","author":"Shike"},{"body":"[Sound Reproduction: The Acoustics and Psychoacoustics of Loudspeakers and Rooms](https://www.amazon.com/Sound-Reproduction-Psychoacoustics-Loudspeakers-Engineering/dp/113892136X)\r\n\r\nHarman has done a lot of speaker preference testing. The testers performed worse with multi channel and \"discontinuous and narrow band signals\". Note that these are double blind critical listening tests. Testers are completely focused on the sound. Add a picture and story to the mix, and I think the differences will be even less.","subreddit_name":"hometheater","author":"driving_for_fun"},{"body":"That makes sense. Control rooms tend to actually be treated.\r\n\r\nIf a control room has 10dB of room gain, I'd say it really needs acoustic treatment. Years ago when LEDE was very popular, getting rid of everything that isn't the direct sound was the goal. It's not unreasonable to end up with a nearly dead room in that case.\r\n\r\nThe paper is dense but it's practically become the Bible for residential listening rooms. Certainly worth the read, in my opinion. It's a compliment to his book [Sound Reproduction: The Acoustics and Psychoacoustics of Loudspeakers and Rooms](https://smile.amazon.com/Sound-Reproduction-Psychoacoustics-Loudspeakers-Engineering/dp/113892136X/) which expands on it quite a bit.","subreddit_name":"audiophile","author":"Umlautica"},{"body":"From a technical standpoint no, you're just choosing which lower bass frequencies go to which speaker. Theoretically speaking it shouldn't sound any different at lower volumes when you change the setting. \r\n\r\nHowever there's a shit ton of variables that effect the sound you hear. Room reflections from floor/ceiling/walls, boundary gain from being near a wall, SBIR which is cancellation based on distance to wall, room modes for your speakers, room modes for your subwoofers, target curve of AVR, quality of AVRs room correction, frequency response of subwoofer/main speaker, which seat within the room your sitting. All those will effect your bass response in your room. If you're interested in understanding more about those definitely do some research it's too complex of a thing to explain all of them without writing a 20 page novel. Home theater gurus on YouTube talks a lot about them. Audioholics has some good webinars on YouTube with Anthony Grimony. Or best yet [this book which would give you an indepth understanding](https://www.amazon.com/dp/113892136X/) which would surpass my knowledge. \r\n\r\nSo depending on how each of those variables effects the sound you could have a boost or dip in bass at a specific frequency which would if you include or exclude it via your crossover could increase or decrease the bass you hear so the more it increases the overall balance of the speaker would be effected. \r\n\r\nTldr: it could go either way. As always it depends hence why calibrated microphone or doing a lot research to gain an advanced understanding of acoustics.","subreddit_name":"hometheater","author":"TyGamer125"},{"body":"I highly recommend the book \"Sound Reproduction: The Acoustics and Psychoacoustics of Loudspeakers and Rooms (Audio Engineering Society Presents) 3rd Edition\" by Floyd E. Toole.   \r\n\r\n\r\nThe author does a good job of explaining (among other things) how/why humans are pretty bad at removing bias when listening/reviewing audio gear. He focuses on speakers, but a lot of it extends to other pieces of audio gear as well. In his many (many...as in decades worth) of tests, both in simulated living spaces (designed to replicate a living room) and in anechoic listening chambers, he found that listeners were pretty good at picking out good vs bad (or, good vs less good) speakers in blind tests and they almost always align with technical measurements. There were, however differences between trained critical listeners (the best), musicians (somewhere in the middle), and laypersons, but all groups do relatively well.   \r\n\r\n\r\nBut as soon as one or more of the products are known, the results skew wildly. If you know what you're listening to, you're going to have bias. There's no escaping it, no matter how \"good\" you think you might be at critical listening. The author is very critical of the majority of audiophile reviews for this very reason.  \r\n\r\n\r\nhttps://www.amazon.com/dp/113892136X?psc=1\u0026amp;ref=ppx\\_yo2\\_dt\\_b\\_product\\_details","subreddit_name":"audiophile","author":"planet_irata"},{"body":"\u0026gt; Who is we? lol  \r\n  \r\nFloyd Toole wrote the book on loudspeaker design (literally [wrote the book](https://www.amazon.de/Sound-Reproduction-Psychoacoustics-Loudspeakers-Engineering-dp-113892136X/dp/113892136X/ref=dp_ob_title_bk)).  \r\nIt has been generally accepted as the de-facto standard.","subreddit_name":"headphones","author":"oratory1990"},{"body":"If you're a representative, or authorized dealer for a brand like Denon as an example you go through a pretty extension training suite(either in person or on-line) for pretty much any product you may sell. Then they send you updates to that annually and sometimes more frequently if there's been something introduced that they feel you should be required to \"certify\" on to best represent their brand.\r\n\r\nBut, otherwise, it's a lot of hands on experience combined with researching things online or in books(anyone remember those?)..:)\r\n\r\nFor example, goto you tube and search for \"floyd toole\" or even better grab his new book at amazon.\r\n\r\nhttps://www.amazon.com/Sound-Reproduction-Psychoacoustics-Loudspeakers-Engineering/dp/113892136X\r\n\r\nOther than the above I would guess most professionals just try to share their general knowledge as time allows and usually stick to their respective fields. A television engineer might not be very active in a subwoofer forum for example..:)","subreddit_name":"hometheater","author":"TVodhanel"},{"body":"Well, measurements like directivity and estimated room response are very good indicators of the sound of a speaker. For example [Audioholics has made quite a few articles](https://www.audioholics.com/loudspeaker-design/measure-loudspeaker-performance) trying to explain that to people. Of course [the Dr. Floyd Toole’s book](https://www.amazon.com/Sound-Reproduction-Psychoacoustics-Loudspeakers-Engineering-dp-113892136X/dp/113892136X/) and all other research he has been part of are perhaps the most known research of that.","subreddit_name":"audiophile","author":"iNetRunner"},{"body":"Because with off-axis measurements you know the radiation pattern of each driver.\r\n\r\nThis allows you to blend the drivers in such a way that it maintains a consistent radiation pattern, leading to a speaker with slowly declining sound power (total radiated energy). Combined with a flat on-axis response, this results in a good quality speaker which people enjoy. This is based on research conducted by Floyd Toole and Sean Olive, with published AES papers. Here is a talk by Floyd Toole, and a Sean Olive interview which covers this. Also Floyd Toole has a book about it.\r\n\r\nhttps://www.youtube.com/watch?v=zrpUDuUtxPM\r\n\r\nhttps://www.youtube.com/watch?v=IEtYH03pfOI\r\n\r\nhttps://www.amazon.com/Sound-Reproduction-Psychoacoustics-Loudspeakers-Engineering-dp-113892136X/dp/113892136X\r\n\r\nYou might compromise the radiation pattern for the sake of power handling. For example, you cannot realistically crossover a 1\" dome tweeter at 1000Hz, even with a 4th order slope. The speaker wouldn't be able to play loudly without audibly distorting, even though the radiation pattern of the finished product would look better than using a 2000Hz crossover.\r\n\r\nZ offset is a somewhat misunderstood topic in speaker design. Lets say you are using a dome tweeter with no waveguide, so the acoustic centre of the tweeter is further forward than the woofer acoustic centre. This is going to cause a time arrival difference, and applying a Z offset does not eliminate that difference. What it does is move the anomaly in the vertical radiation pattern. Is this an audible problem, well it depends on how big the offset is. You still hear the offset because of the reflections off your ceiling and floor, but it might not be noticeable.\r\n\r\nTo explain things in practical terms, it may help to look at the data collected from an optimized speaker.\r\n\r\nhttps://www.audiosciencereview.com/forum/index.php?threads/kef-r3-speaker-review.12021/\r\n\r\nThe on-axis is obviously quite flat, but you will notice the early reflections, and sound power decline smoothly. This is because the tweeter and mid-range driver are a coaxial arrangement. Meaning the time arrival is perfectly aligned regardless of orientation, and the mid-range cone acts a waveguide for the tweeter, aligning the radiation pattern in the crossover region of 3000Hz. The woofer is crossed at 400Hz, low enough that it barely disturbs the radiation pattern.\r\n\r\nThis leads to the speaker having a preference score of 8.1 when used with good quality subwoofers, one of the highest for any passive loudspeaker. This score comes from a formula derived from the speaker research done at Harman. It isn't infallible, but a good starting point when designing a speaker.\r\n\r\nhttps://patents.google.com/patent/US20050195982A1/en\r\n\r\nParticularly, there is some debate over wide and narrow radiation patterns. For example, trading spaciousness vs imaging precision, due to the different level of room reflections. Here is an example of a well designed 2 way horn loaded speaker. While the on-axis has problems, the sound power is excellent, meaning that with EQ to correct the on-axis, it would become an excellent speaker.\r\n\r\nhttps://www.erinsaudiocorner.com/loudspeakers/diysg_htm12v2/","subreddit_name":"diysound","author":"DZCreeper"},{"body":"1. [Sound Reproduction: The Acoustics and Psychoacoustics of Loudspeakers and Rooms](https://www.amazon.com/Sound-Reproduction-Psychoacoustics-Loudspeakers-Engineering/dp/113892136X) - really amazing book, I'm on my second read-through.\r\n\r\n\r\n2. [THE ABSOLUTE SOUND - Illustrated History of High-End Audio](https://store.theabsolutesound.com/collections/books/products/illustrated-history-of-high-end-audio-volume-two-electronics) - note that there are two parts\r\n\r\n\r\n3. [Master Handbook of Acoustics](https://smile.amazon.com/Master-Handbook-Acoustics-Alton-Everest/dp/0071603328) -  This genre of of books shouldn't be too hard to find at the library.\r\n\r\nMany more resources on https://www.reddit.com/r/audiophile/wiki/guide","subreddit_name":"StereoAdvice","author":"Umlautica"},{"body":"Floyd E. Toole\r\n\r\n[https://www.amazon.com/Sound-Reproduction-Psychoacoustics-Loudspeakers-Engineering/dp/113892136X](https://www.amazon.com/Sound-Reproduction-Psychoacoustics-Loudspeakers-Engineering/dp/113892136X)\r\n\r\n\u0026amp;#x200B;\r\n\r\nYou might also have a look here: https://www.audiosciencereview.com/forum/index.php?forums/audio-reference-library.30/","subreddit_name":"audio","author":"ConsciousNoise5690"},{"body":"Floyd E'Toole\r\n\r\nhttps://www.amazon.com/Sound-Reproduction-Psychoacoustics-Loudspeakers-Engineering/dp/113892136X","subreddit_name":"audio","author":"ConsciousNoise5690"},{"body":"When you’re ready, [this book covers most of the basics of speaker design](https://www.amazon.com/dp/113892136X/ref=cm_sw_r_awdo_BF65HP3C19V7EN8CHGJ9)","subreddit_name":"SoundSystem","author":"D_Livs"},{"body":"https://www.amazon.com/Sound-Reproduction-Psychoacoustics-Loudspeakers-Engineering-dp-113892136X/dp/113892136X\r\n\r\nI think that book is a great place to start, Floyd Toole also did a 1 hour presentation which sum up the key points.\r\n\r\nhttps://www.youtube.com/watch?v=zrpUDuUtxPM\r\n\r\nFor people looking to actually build speakers, I usually start with these two:\r\n\r\nhttps://www.parts-express.com/Loudspeaker-Design-Cookbook-7th-Edition-Book-500-035\r\n\r\nhttps://www.amazon.com/High-Performance-Loudspeakers-Optimising-Loudspeaker/dp/1118413539\r\n\r\n-----------\r\n\r\nWhen it comes to sound, modern research show us that the natural human preference is for a flat on-axis sound, with off-axis sound that gradually declines in volume, ideally tracking the on-axis. When such speakers are placed in a typical room, they create a frequency response which has a slight downward trend, meaning the bass is prominent, while treble is tapered off. There is variance between casual and experienced listeners, but everyone follows the same trend line.\r\n\r\nHorn loading is a method to improve the impedance matching of a compression driver. When a raw driver is used, the efficiency is poor, because only the air molecules directly in front of the driver are coupled to the pressure wave being created. With a horn, more force can be exerted for the same input power, while at the same time controlling the directivity (off-axis response). You can use horn loading for woofers and mid-range drivers as well, but the sizing becomes problematic for residential use.\r\n\r\nIf you have other questions, feel free to make a post in /r/diyaudio or /r/diysound and tag me with /u/DZCreeper, I can answer most questions or point you at good resources.","subreddit_name":"hometheater","author":"DZCreeper"}]}