bose lifestyle

[toomanycats]

My speakers are 6.5 feet tall 17 inches deep and 11 inches wide. When viewed from the side they for a right sided triangle. They resonate at 29Hz as the BF20 Pioneers have an Fs of 29hz. The tweeters are Piezoelectric and need no crossovers (if you don't know why then you don't know what you are talking about). The speakers are therefore in phase. There is a 2.5" rectangular port in the bottom of the speakers to accommodate the rear wave. I have a Miller Kreisel subwoofer for the deep stuff. I have installed many Bose systems in many houses and always "smile" when I hear people say "How good they sound". It is too bad that a generation of people have not heard 3 dimensional music as CD's have removed so much information that the front to back placement of music is lost. "Sounds good" is a relative term and if you are happy with what you have then great. Your missing a lot of musical information on those Bose systems no matter where you place the speakers. BUT FOR ANYONE TO INSINUATE THAT RFBURNS IS BABBLING ABOUT ANYTHING IS OBVIOUSLY NOT CAPABLE OF PARTICIPATING IN THIS LEVEL OF DISCOURSE. The only babbling going on here is by Olyteddy, you are out of your league.

[MikeyBK]

All this audio tech talk is 'all' 'Babble' to me...I know what sounds good to me by using my 'ears'......but I know where you guys are coming from, just like video and bitrates affecting video quality, so to with audio I'm sure.


And your right toomanycats, 'sounds good' is relative to personal tastes. I personally love bass-rich sound, thus my preference for most Bose systems.
I remember being in a Bose showcase in which they had a 'one' 2' X 2' Bose speaker, and that badboy literally shook the walls, and with no 'muffled' bass as you stated. Can you imagine a 'pair' of 6 ft Bose!!??!!

Anyways, I'm sure every company has different levels of sound output systems, and I personally am blown away by the sound coming out of this pair of 6 in tall, 3 in wide Bose computer speakers..

[toomanycats]

Actually, those little Bose speakers are pretty awesome. I owned a pair of Bose 901's in the seventy's, talk about bass!! One thing about computer speakers that is overlooked is the fact that you can be so close to them and hear nothing coming out of them when they are "idling" ("quiessing"). I have heard really expensive systems buzz when you put your ear right next to the loudspeaker. This is something that would never be tolerated on computer speakers as you are always close to them. My brother in law spent a "couple" of grand on an upscale Bose system and after he heard my home theater setup he felt as if he had spent too much. I personally think the lower end Bose stuff is a pretty good bang for the buck, it is the expensive stuff that I don't like. Their noise canceling headphones are incredible, especially if you fly a lot. It is funny how sound preference can be so subjective but almost anybody can tell when a videos/movies quality sucks. Just for the record, Bose was a really easy company to deal with when I used to repair their systems. They sold me whatever repair part I needed. They really cared about their customers which is something that cannot be said for every company.

[RFBurns]

Thanks for the support! I only try to inform with the knowledge I have. Knowledge shared is the greatest gift of all.

Waveguides do incredible things. They can focus certian frequencies which gives increased amplitude, they can direct waves around things and keep out unwanted junk.

With the right combination of these, the room, its contents, an incredible result can be achieved with small speakers. History has proven the tuned port waveguide technique dating back to the 30's during the early years of sound system engineering. Much of the loudspeaker cabinets back then used waveguide techniques to increase amplitude (loudness) as well as direct the sound and cancel out sound in unwanted areas.

Today large concert hall cabinets also use waveguide cabinets. These are the cream of the crop in tuned port cabinets. With these and using a number of them placed just right and at the right angles, you can fill a huge auditorium with rich sound that covers the entire audience area without having to put in tons of speaker cabinets to get the same results. These waveguide cabinets also help prevent feedback by keeping the emitted sound away from the microphones on the set/stage.

To get an idea of how a waveguide for sound can work, take an empty paper towel core and a small pocket radio. Listen to the radio by itself, then put the empty paper towl core in front of the radios speaker. Hold both about arms length in front of you and then move the paper towel core a few inches to the left and right while keeping it close to the small radio speaker. Note how the sound seems to move from left to right. The paper towel core is in fact acting like a waveguide giving you control of how the sound is directed when moving the core to the left or right. Try a funnel along with the paper towel core and this will give an example of how waveguide helps increase amplitude as well as provide directional control.

[RFBurns]

Here is a free nifty little piece of software for speaker cabinet design. It will plot on a frequency and amplitude graph the response curves per paramaters input within the fields. Simply enter your desired box parameters and it will show you the expected response and performance.

http://www.cetest.nl/zips/boxplot.zip

[RFBurns]

For those who just cannot part with that good ol warm milky sound from tube type audio gear, here is a link to a very well designed tube amplifier that with some minor changes, can operate either in a mobile environment or in a home setting.

http://www.montagar.com/~patj/tubeart.htm

Although the amplifier is primarily built for mobile operation, one can simply leave out the 12 volt dc to ac inverters and replace them with typical power supplies that operate on household ac current.

This particular amplifer is an excellent introduction to tube amp design. At a plate voltage of 400 volts, this puppy will push some air with appropriate speakers! Note the output of the unit incorporates a multi-tap transformer so that a variety of impeadance speakers can be used.

Enjoy!

[toomanycats]

@RFBurns, I doubt Bose's patents would hold up in court because, as you mentioned, the technology has been around since the 30's. I have Sony Home Theater 5.1 Dolby Digital for movies. I have a 1960 Scott LC290 with the original matching pre-amplifier I use for Stereo music. DSP (DigitalSoundProcessing) on music originally recorded in stereo just sounds awful to me (i.e. Dark Side of the Moon, Pink Floyd). The tube amp plugged into my 1/4 wave tube speakers sounds excellent, detailed, and the Piezo electrics sound crisp. Since this amp only pushes 45 watts the Piezos are perfect. The LC290 will create 10hz wave form (not the a human could ever hear it) so one must be careful as speakers can still be blown. I blew an old set of Genesis II speakers as they could not handle the bass, lousy crossover design I guess.

I have always appreciated your willingness to share knowledge. I think that some here may not appreciate the level of expertise that you offer, being a mere electronic technician, I am in awe of you insights and willingness to share so openly.

[olyteddy]

@RF, sound travels at 1100 Feet per second. A 40 Hz sound wave therefore has 40 cycles in that 1100 feet, making each one 27.5 feet long. a 40 HZ radio wave would travel 186,000 Miles in a second making each cycle 4,650 miles long. I'll diagram the corner horn when I get a chance.

[olyteddy]

This is a cut away top view. The purple is the room walls. The Green is the speaker. The blue is the horn, made of 3/4" plywood. the magenta is the path of the wave off the back of the speaker. The horn design delays the wave off the back of the speaker by about 12 to 15 feet, causing that wave to be in phase (boosting) the wave off the front of the speaker. It's about half a wavelength of 35 Hz, resulting in roughly twice the bass at that frequency.

[toomanycats]

A properly tuned folded horn will resonate at the Fs. of the speaker. That does not mean your getting the full 40Hz sound wave. You are getting 1/4 of the waveform resonating at the speaker Fs. which is "helped" by phasing the rear wave to closely match the front wave. The problem with folded horns is that the rearwave bounces inside the cabinet and must be dampened to tune the waveform and prevent sound waves from interfering with each other. That is why I chose a tapered 1/4 wave tube. It resonates (the speaker that is) at 29 Hz allowing you to hear the speakers 29Hz waveform at 1/4 of the wavelength. Radio waveforms are a completely diffeent thing as they are not afected by density and temperature as sound waves are.

[toomanycats]

I just caught your picture, it sounds like we are all saying the same thing, just differently. (words suck). I built a box for a pair of electrostatic panels that I made some years back to try and enhance the rear wave but it proved to difficult. The delay of the rear wave can be enhanced (or tuned) with Acousta-stuff. Too much will change the impedance as the speaker will have to work harder.

P.S. I think the diference in opinion here is rooted in the coverage provided by the 1/2 or 1/4 waveform as opposed to the full wave form. The smaller wave form will fullfill the listening requirements for the average size listening area as opposed to a full waveform that would be used for a larger venue.

[idevelop.tv]

Here is a free nifty little piece of software for speaker cabinet design. It will plot on a frequency and amplitude graph the response curves per paramaters input within the fields. Simply enter your desired box parameters and it will show you the expected response and performance.

http://www.cetest.nl/zips/boxplot.zip

great link. thanks!.

[Chewy]

A friend built a couple of "state of the art" speakers, he had already gotten in trouble at certain large events with his sound systems when they overpowered conventional speaker banks being used by the main event/attraction in outdoor street festivals.

Last 2 boxes were 2x4x4, they were a little too much even for a 30,000
sq foot area. They do a good job in a coliseum/basketball arena with relative low amperage.