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Car Forum / Mazda / Mazda Miata / July 2004'99 Bose
The driver's side door speaker has been sounding very distorted for the past couple of weeks. I don't know what caused the speaker to fail, as I haven't turned the system up loud for some time. I decided to fix the problem myself. I took out the screws out that hold the top of the door handle and the concealed one under the storage slot carpet at the bottom of the handle. The plastic retainers came out quite easily. Then I went to remove the small black screw that holds the black cup beneath the door handle. It had apparently been installed with an air driver. The philips slot in the top of the screw immediately stripped out. I couldn't loosen the screw and had to drill the head of the screw off. The door panel pulled off without further problems. The Bose door speaker was exposed. It is an 8" unit that is held in place with 4 screws. I removed the screws and removed it. I am not impressed with the Bose door speaker. It is a piece of junk. I decided I didn't want to replace both speakers at this time, so I purchased a replacement speaker at my Mazda Dealer. The speaker with tax cost $175. Ouch! The re-assembly went okay, and I can listen to tunes again without the buzzy distortion. I took the old speaker apart. The voice coil had been scraping against the magnet. The voice looked like it was good for about 50 watts, but the end of sleeve it was bent where it had bottomed out inside the magnet. So much for a 200 watt Bose system......... Final word of wisdom: Don't crank to max volume on your system or you will be buying new speakers! My 99 has 6 X 8 inch speakers. There don't seem to be very many choices in that size. Are your speakers 8 inch round? Has anyone tried Pioneer 6 X 8 as a replacement? Walmart has them for $56... here's the link... http://www.walmart.com/catalog/search-ng.gsp?search_constraint=0&search_query=ca r+speakers&ics=20&ico=0&Continue.x=19&Continue.y=9 > The driver's side door speaker has been sounding very distorted for the past > couple of weeks. I don't know what caused the speaker to fail, as I haven't [quoted text clipped - 24 lines] > Final word of wisdom: Don't crank to max volume on your system or you will > be buying new speakers! Yes, it is a round speaker with four screw mounting holes. The speaker measures 8" in diameter between holes. The design is a little strange. It was designed to maximize bass response. It has a cheap plastic tube about the size of the speaker at the back to increase low frequency resonance. The cone does not have any hard surfaces to enhance mid-range. The voice coil is edge-wound and flat to handle high current. The magnet is located on the front of the speaker instead of the back. I guess they save a little space that way. If one or both speakers fail again I will replace them with a couple of JBLs. I can get a pair for what one Bose replacement costs. > My 99 has 6 X 8 inch speakers. There don't seem to be very many choices in > that size. Are your speakers 8 inch round? Has anyone tried Pioneer 6 X 8 > as a replacement? Walmart has them for $56... here's the link... http://www.walmart.com/catalog/search-ng.gsp?search_constraint=0&search_query=ca r+speakers&ics=20&ico=0&Continue.x=19&Continue.y=9 > > The driver's side door speaker has been sounding very distorted for the > past [quoted text clipped - 34 lines] > will > > be buying new speakers! The "cheap plastic tube" is to keep water off the speaker. The BOSE speaker in the 99 Miata is a special 1/2 ohm unit and is mated with the BOSE amp. Using conventional 4 ohm speakers would probably give a low max volume. >Yes, it is a round speaker with four screw mounting holes. The speaker >measures 8" in diameter between holes. The design is a little strange. It [quoted text clipped - 7 lines] >If one or both speakers fail again I will replace them with a couple of >JBLs. I can get a pair for what one Bose replacement costs. I don't know how the "1/2 ohm theory" originated. I have seen it floating around the internet in other places. The statement is incorrect. The plastic tube on the back of the Bose might provide some protection from water running down the inside of the door, but the speaker cone is not exposed to the inside of the door. The water resistant spider (the accordian voice coil suspension) is all that might be exposed to water. The speaker impedance is not the DC resistance. The voice coil on this unit consists of about 80 turns of flattened wire, .75 inches in length, with a radius of .68 inches. This calculates out to about 217 microhenries. I do not know at what frequency the Bose speaker impedance is figured, but at 300 hertz it works out to be about 4 ohms. At 1 khz it is about 14 ohms. Bipolar transistor power amps loose efficiency when connected to loads below 2 ohms. Four ohms minimum seems to be the design standard in the industry. As for volume loss when substituting high impedance speakers, the volume reduction on high efficiency speakers is nominal. When you half the power you are down by 3 db. Miata owners that have Bose systems can install other 8" round speakers without loosing volume. One benefit of speaker replacement would be to improve mid-range volume, and improve the balance between the bass and mid frequencies. > The "cheap plastic tube" is to keep water off the speaker. The BOSE > speaker in the 99 Miata is a special 1/2 ohm unit and is mated with [quoted text clipped - 12 lines] > >If one or both speakers fail again I will replace them with a couple of > >JBLs. I can get a pair for what one Bose replacement costs. I've seen it on the internet too. Here are some of the places: http://members.fortunecity.com/jasoncuadra/audio/bose/bose_rta.html http://stephen.fosketts.net/miata/nbaudio/index.html http://www.clearwateraudio.com/cwc8b.htm An awful lot of people seem to believe it. That's hardly proof of course, but until I see an actual frequency / impedance graph that says otherwise I'm going to stay with the 1/2 ohm theory. >I don't know how the "1/2 ohm theory" originated. I have seen it floating >around the internet in other places. The statement is incorrect. The plastic [quoted text clipped - 38 lines] >> >If one or both speakers fail again I will replace them with a couple of >> >JBLs. I can get a pair for what one Bose replacement costs. Some comments on the below websites: > I've seen it on the internet too. Here are some of the places: > > http://members.fortunecity.com/jasoncuadra/audio/bose/bose_rta.html Jason has done a good job in displaying the frequency response of the system using his Real Time Analyzer, and has accurately described the acoustics of the speaker and it's door enclosure. The technical analysis of the Bose power amplifier and speaker system is not exactly right. He says, "The fact that the pink line is around 2dB down in places means that the wire resistance to the drivers is significant. It's losing about 2dB of power, which is something like a 30% loss of power in the wires. The Bose system uses 0.5 ohm drivers so that the power amp, with no switching power supply, delivering 12V peak to the drivers, can theoretically deliver >140W into a 0.5 ohm load. The skinny speaker wires means 30% less power is getting to the speakers." Here Jason exposes his lack of technical understanding. The pink line is his graph is down 2 db because the amplifier load causes a drop due to all resistance in the coupling, not just the wire, but the amplifier outputs also. The speaker is not 100% resistive and causes further variations from the -2 db attenuation. If he had used a non-inductive load to graph the output he could have determined the coupling losses and damping factor of the system. Jason may have measured the DC resistance of the speaker with an ohm meter. It does measure .5 ohms. A speaker is an inductive load and the speaker impedance can not be determined by measuring the DC resistance. As the audio signal increases in frequency the impedance of the speaker increases, though the increase is not quite linear due to the mechanical design of the speaker. Direct coupled audio power amplifier outputs are capacitive in nature, which assists in the coupling to an inductive load (speaker). Anyway, loosing 2 db isn't a problem. The Bose system is capable of delivering in excess of 100db SPL at power levels of less than 50 watts. > http://stephen.fosketts.net/miata/nbaudio/index.html Fosketts says on his website, "special low-resistance (.5-Ohm) speakers." Resistance and impedance are not the same. He says that the tweeter is 4 ohm. I don't know if the tweeter says 4 ohms on it. With some tweeters the DC resistance and the AC impedance may be close, as a tweeter is capable of delivering high volume levels at relatively low power. Fosketts also states, "This means that removing the Bose system (say, to replace the speakers) requires replacing all of the speakers and wiring past or removing the Bose amplifier." This is not true. Many Miata owners have upgraded to a better quality door speaker that improves mid-frequency response and system linearity. I suspect he is in the business of selling replacement autosound system. > http://www.clearwateraudio.com/cwc8b.htm Here is a company that is clearly in the business of selling new systems for the Miata. They state, "We manufacture a system to accommodate this need. The Bose? replacement system is designed to work seamlessly with the factory amplifier. The impedance of this woofer is ? ohm, just like the factory speaker." Here they say their replacement is 1/2 ohm impedance. I doubt if they manufacture these speakers, and if their replacement is the same as the Bose speaker it isn't 1/2 ohm impedance. This is a sales organization that is not careful about providing technical information on the products they sell. The Bose door speaker is not just a woofer. It also is responsible for reproduction of the mid-range frequencies. > An awful lot of people seem to believe it. That's hardly proof of > course, but until I see an actual frequency / impedance graph that > says otherwise I'm going to stay with the 1/2 ohm theory. The reason there is so much mis-information and confusion on Bose systems is because Bose does not publish specifications on their systems. In answer to the FAQ, "Can I get a list of technical specifications?", Bose answers, "No, because our custom-engineered, complete system solutions largely supersede conventional audio measurements. Even some basic building blocks have been redefined-including amplifiers, speakers and equalizers. But most importantly, our integrated systems deliver results significantly different from those of conventional systems with individual, unmatched components. With a Bose automotive sound system, the location and design of the speakers can be much more important factors in determining output than a wattage power rating. The bottom line? The best way to test a Bose system's sound quality is to use your ears, not a list of specifications. " I met Dr. Amar G. Bose in 1970. He was a Professor at M.I.T. He had started his company in 1964 and by 1968 introduced the Bose 901 Direct/Reflecting speaker system. The Bose 901 used nine 4" speakers in a small acoustic suspension cabinet. Eight of the speakers faced forward, while a ninth was mounted on the back of the cabinet. Each speaker was rated at 30 watts. The system used no internal frequency compensation networks and would handle 270 watts RMS. The small speakers with low mass provided excellent transient response. The rear mounted speaker provided a reflected wave off walls or surfaces behind the speakers which added a reverb to the sounds. When properly placed the reverb would be 10 to 20 milliseconds. The speaker system came with an equalization box to boost the level of low frequencies. The box needed to be connected using tape-in/tape-out connections on the amplifier, or to be placed between preamp and amp. The equalization box offered few adjustments, and the bass boost was about 24 db. The high amount of bass boost more than compensated for the bass attenuation from the small speaker boxes. This was the first hi-fi speaker system designed for the customer that liked exaggerated bass response. All his speaker systems since the 901 are designed to accentuate the low frequencies. Serious audiophiles do not like Bose speaker systems, but it seems to be popular these days to install a high power amplifier and sub-woofer in your car. Well I agree with you that DC resistance is not the same as impedance. However in most cases it is in the ballpark. A "4 ohm" driver will have a DC around 3.6, an "8 ohm" driver will have a DC of 7.2 and so forth. The .5 ohm DC resistance of the 8" BOSE woofer under discussion certainly gives the appearance that somewhere in its impedance curve it will have a lower impedance than most amps can handle. So far your response has been to say that anyone who says that the BOSE woofers in the Miata are low impedance either: 1) doesn't know what they are talking about. 2) is lying in order to sell something. or both. However you have not yet offered any proof to back your assertions that the BOSE woofer is not low impedance or that conventional 4 ohm speakers will work and provide satisfactory sound levels. Until such proof is forthcoming I'm going to keep these theories in the "possible, but not probable" pile. If it is possible to use 4 ohm woofers and you find the BOSE woofer so deficient, it begs the question: Why didn't you replace your defective BOSE driver with a pair of 4 ohm woofers instead of shelling out $175 for one factory BOSE woofer? >Some comments on the below websites: > [quoted text clipped - 97 lines] >do not like Bose speaker systems, but it seems to be popular these days to >install a high power amplifier and sub-woofer in your car. Natman, I did give you the dimensions of the voice coil. Anyone with basic algebra skills can calculate the inductive reactance of the voice coil. Using the discovered "L" you can calculate the impedance. If you have a Miata with a Bose system, it is easy to do a dynamic impedance test. Use a test CD with your choice of audio tone. Disconnect the door speaker and insert an eight ohm resistor in it's place. Play the tone and set a reference level on an AC voltmeter of eight volts. Remove the resistor and reconnect the speaker. Read the voltage at the same setting. You will be reading the impedance directly for the frequency you are playing off your test disk. Low power speakers use small gauge round wire for the voice coil. When small wire is used, the DC resistance is higher and more of the audio current is dissapated in heat rather than motion. In higher power applications where the voice coil is mostly resistive the speaker efficiency is low, and the heat generated can easily cause speaker failure. James Lansing with his JBL company pioneered the edge wound voice coil that was introduced in the model LE8-T eight inch extended range driver over forty years ago. The wire was flattened and varnished before winding on the sleeve. The advantage of using flat wire for the voice coil is that you can get the same number of turns per inch as smaller wire, and the same load impedance with a much higher current and power handling ability. The DC resistance of an edge wound voice coil is much lower than those using conventional wound coils. One thing that is not obvious is that the impedance of the speaker goes very high at low frequencies. The effect happens as the coil resonates. I didn't measure it on the Bose, but I suspect that the impedance rises to over 20 ohms. An increase can also occurs at the second harmonic of voice coil resonance. Very little audio with content below 30 hz is available off CD or radio broadcast. If the amplifier is DC coupled it might deliver audio down to about 10 hz, but the Bose door speaker that is in the Miata presents a safe impedance to any amplifier that is capable of reproducing sub-audible frequencies. Jason Cuadra did a good job of explaining why the Bose door speaker is not the choice of an audiophile. It's partly the speaker's fault, but the door makes a poor enclosure. An acoustic suspension enclosure would offer much smoother response and better overall fidelity. The new Miata system with speakers on either side of the wind blocker has to be a big improvement. I have wondered why Mazda dropped the idea of headrest speakers. I didn't install another brand of replacements speakers because: 1. I didn't want to take the time to disassemble the passenger door to install a matching unit. 2. I didn't want to design and build a baffle/enclosure to install in the doors 3. Once the Miata is rolling, the audio fidelity can't be appreciated! 4. In case I sell the car I can tell the buyer that he has a Bose Audio System 5. Some passengers are impressed by that thumping noise as I roll down the road I do have a pair of JBL GTO625 that are rated a 60 watts RMS. They sound great on the Bose head, but I am using them in my studio for recording monitors and didn't want to waste them in the Miata. These speakers are very efficient and more than loud enough for use in my car. > Well I agree with you that DC resistance is not the same as impedance. > However in most cases it is in the ballpark. A "4 ohm" driver will [quoted text clipped - 124 lines] > >do not like Bose speaker systems, but it seems to be popular these days to > >install a high power amplifier and sub-woofer in your car. Thanks for a this constructive post. I liked your list of reasons for keeping the stock driver. I especially agree with reasons 3 & 4. There are a lot of people who knee jerk that the only thing to do is to rip out everything BOSE and start over. For *my* use the Miata is just not cut out to be the platform for a really top end system. I also must sadly concur with reason #5. There seems to be an entire generation that is being brainwashed into thinking that bass is *supposed* to sound like that. Despite its flaws in stock form it's better than the average OEM system. I believe that it could be a good deal better yet with some simple modifications. First the door IS very resonant, both in the metal and the door panel. Some sound deadener and maybe a few wood ribs should improve things. The nice thing about door improvements is that they will still improve sound even if you switch to different drivers later. Next is the lack of any crossover for the woofer. An 8" woofer is awfully large to run free. The addition of a coil to limit high frequencies should clean up the mid range. Finally, as you pointed out in an earlier post, BOSE loves to boost EQ in the bass. It certainly sounds like they have overboosted the bass in this application. Any thoughts about using a notch filter to tone it down to realistic levels? In order to do the crossover and the notch filter, a frequency / impedance graph would be needed. The method you suggested sounds interesting. Could you provide a bit more detail, especially: "Play the tone and set a reference level on an AC voltmeter of eight volts. Remove the resistor and reconnect the speaker. Read the voltage at the same setting." >Natman, > [quoted text clipped - 222 lines] >to >> >install a high power amplifier and sub-woofer in your car. > platform for a really top end system. I also must sadly concur with > reason #5. There seems to be an entire generation that is being > brainwashed into thinking that bass is *supposed* to sound like that. Bingo!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!! I've tried and tried (I love music) to show my 16 y/o daughter what musical BALANCE is. She's not the least bit interested in listening to any kind of balanced sound. Wonder how many of these stupid kids are going to be 50% deaf in 10 years. > I liked your list of reasons for keeping the stock driver. I > especially agree with reasons 3 & 4. There are a lot of people who [quoted text clipped - 3 lines] > reason #5. There seems to be an entire generation that is being > brainwashed into thinking that bass is *supposed* to sound like that. Minor point. I don't think anyone is "brainwashed" into liking a boomy bass-heavy sound. Bass provides the a bone-shaking concert/club feel...and many people like it. No, they are not audiophiles and no the sound is not accurate for acoustic music, but they prefer it that way. Just like some people prefer super sweet breakfast cereal or soda or Red Bull versus those who savor wine or scotch. There's satisfaction for aficionados and there's primal satisfaction... -John >> I liked your list of reasons for keeping the stock driver. I >> especially agree with reasons 3 & 4. There are a lot of people who [quoted text clipped - 15 lines] > > -John Gotta disagree, much of todays kids music relies totally on these hugely exagerated bass riffs. Kids that grow up on this crap (not because of the bass) DO become "brainwashed" into thinking that is what music is supposed to sound like. > Gotta disagree, much of todays kids music relies totally on these hugely > exagerated bass riffs. Kids that grow up on this crap (not because of the > bass) DO become "brainwashed" into thinking that is what music is supposed > to sound like. I don't know what you mean by 'brainwashed.' Just what IS music supposed to sound like? Classical? Choral? Jazz? Industrial? Atonal? Experimental? Vocals? Reggae? Rap? Heavy Metal? Variety is the spice of life...all of these and more are present in my own collection... It is true that most kids grow up on top 40 radio, which is calculated and targeted for them. There have been many generations of teen boy bands (e.g. New Kids on the Block, N-Sync) that pubescent girls fall for year after year. Teen boys tend to fall for more aggressive music, be it heavy metal or rap/hip-hop. Many people never explore beyond what's hot at the moment, many never explore beyond the very formulaic top 40. On the other hand, some get stuck on what "music is SUPPOSED to sound like" so they never try anything new. Sometimes it takes years before people understand the new style--then opinions change. No genre is all "crap," for there are always innovators who create something unique. Certain genres (especially heavy metal and rap) were created in the electronic era and rely on amplified sound. Bass plays a large role because the amplifier is a muscial instrument of the genre. Take time to explore and you may find something you like. -John >> Gotta disagree, much of todays kids music relies totally on these >> hugely exagerated bass riffs. Kids that grow up on this crap (not [quoted text clipped - 26 lines] > > -John you're talking types of music. I'm talking about cranking the bass knob to full NO MATTER what you are listening to. Or in the case of the this pseudo musical crap they pass off these days, it's encoded with the bass hugely overemphasized on the recording. EIther way, it's a totally unbalanced sound that they DO become brainwashed to expect. That is proven every time I get in my daughters car and move the bass knob off FULL gain. And she isn't always listening to rap. Sorry, but my standards for appreciating music require the artist to either SING or be able to play a musical instrument. :) > you're talking types of music. I'm talking about cranking the bass knob > to full NO MATTER what you are listening to. Or in the case of the this > pseudo musical crap they pass off these days, it's encoded with the bass > hugely overemphasized on the recording. Here you are mixing types of music with overemphasized bass..."pseudo musical crap" >EIther way, it's a totally > unbalanced sound that they DO become brainwashed to expect. That is > proven every time I get in my daughters car and move the bass knob off > FULL gain. And she isn't always listening to rap. Again, see my original reply. It provides a club/concert feel and some people prefer this. No brainwashing involved. > Sorry, but my standards for appreciating music require the artist to > either SING or be able to play a musical instrument. :) ????? Once again this appears to be an out of hand rejection of certain types of music...beyond the bass mix. -John "Generic" <generic@scientist.com> wrote in news:40eee9ce$0$89653 $a32e20b9@news.nntpservers.com: >> you're talking types of music. I'm talking about cranking the bass knob >> to full NO MATTER what you are listening to. Or in the case of the this [quoted text clipped - 3 lines] > Here you are mixing types of music with overemphasized bass..."pseudo > musical crap" You seem to be missing my point, which is that no matter WHAT TYPE of music they listen too, they crank the bass up to full. EVEN THE GOOD MUSIC BEING MADE TODAY. >>EIther way, it's a totally >> unbalanced sound that they DO become brainwashed to expect. That is [quoted text clipped - 3 lines] > Again, see my original reply. It provides a club/concert feel and some > people prefer this. No brainwashing involved. I've been to a LOT of concerts, and none of them (save a couple heavy metal bands) had anywhere NEAR the bass emphasis of much of the kids/rap/crap coming out now. SOrry, but that doesn't wash at all. Brainwashing is involved. (we do realize we're using "brainwashing" to mean "they listen to this hugely unbalanced sound and become "used" to it, and then they play ALL MUSIC that way. Don't know what you'd call it............. >> Sorry, but my standards for appreciating music require the artist to >> either SING or be able to play a musical instrument. :) [quoted text clipped - 3 lines] > > -John Got that right. Rap sucks all the way :) > >> to full NO MATTER what you are listening to. Or in the case of the > this [quoted text clipped - 7 lines] > music they listen too, they crank the bass up to full. EVEN THE GOOD > MUSIC BEING MADE TODAY. That point has been taken, but that's not what you said above. You made a comment about the ENCODING of "pseudo musical crap." Some recordings are certainly encoded with massively overemphasized bass. Prodigy's "Fat of the Land" (1997) album springs to mind. The bass is easily 2x or 3x louder than typical. This album has received very solid reviews and is an "essential recording" at Amazon.com. It is, however, aiming for a dance club feel. > I've been to a LOT of concerts, and none of them (save a couple heavy > metal bands) had anywhere NEAR the bass emphasis of much of the > kids/rap/crap coming out now. Again, you are flipping back to a personal dislike for one genre that happens to be bass heavy. >SOrry, but that doesn't wash at all. > Brainwashing is involved. (we do realize we're using "brainwashing" to > mean "they listen to this hugely unbalanced sound and become "used" to > it, and then they play ALL MUSIC that way. Don't know what you'd call > it............. I'd call it a simple preference. Some like apples, some like oranges. If you like a bass heavy sound profile you'll get as close as possible with the equipment available. Such people are not necessarily looking for a realistic sound, but who am I to criticize? -John > Sorry, but my standards for appreciating music require the artist to >either SING or be able to play a musical instrument. :) I totally completely 110% agree! The only reason they "rap" is because they CAN'T sing nor play an instrument. But, they can play a radio. Besides, they must get cramps turning their wrists in and down towards their bodies..,wooooeeeeee :-P ~Cissy <a href="http://members.aol.com/IvaMiata/Krikkit/index2.html">My '90 Mazda Miata</a><br> <i>I love PC adventure games</i> > The only reason they "rap" is because they > CAN'T sing nor play an instrument. Cissy, I don't think that's strictly true. We borrow a lot of DVDs from the county library; it's free, so if it sux we can bail after two minutes then try something else. We watched "8 Mile," a film about rap. Now, I really don't care for rap and never listen to it voluntarily, but the film was pretty good, and taught me to understand rap (well, *good* rap) as a sort of forensic poetry, an artistic exhibition of language skills to make a point. You might not agree with the point, but some of the practitioners are quite talented, with an excellent command of English. As for car radios, I think everyone must know by now that I don't even know if mine works, since the only part of it I ever use is the clock. Since my living room contains a high-resolution audio system worth about 4X the current value of my Miata, to me any car stereo is just a toy. It's the last thing in the world on which I'd waste any money or time.  SignatureLanny Chambers, St. Louis, USA '94C the alignment page: http://www.hummingbirds.net/alignment.html > > The only reason they "rap" is because they > > CAN'T sing nor play an instrument. [quoted text clipped - 8 lines] > the practitioners are quite talented, with an excellent command of > English. i must agree with Lanny. some rappers are very creative, expressive, articulate observers of comtemporary urban life. the genre is not what i prefer to listen to but that doesn't mean it's all crap. every generation thinks their music is the best; anything before is irrelevant, sentimental drivel and anything after is only noise. i can still hear my father saying that my Emerson, Lake, and Palmer or Led Zepplin or Deep Purple or Pink Floyd albums were "just a bunch of no-talent noise." > As for car radios, I think everyone must know by now that I don't even > know if mine works, since the only part of it I ever use is the clock. > Since my living room contains a high-resolution audio system worth about > 4X the current value of my Miata, to me any car stereo is just a toy. > It's the last thing in the world on which I'd waste any money or time. again, i agree. i too have been spoiled by high quality home audio. my car stereo is a medium-priced, name-brand aftermarket system the PO installled. it sounds horrible. i don't understand why some people spend so much on car audio systems when cars are not very good listening chambers to begin with. to me, all car audio is a less-than-satisfactory compromise. but, each to his own. dave > dave Of course you are both right. :) I HAVE heard some rap that I thought quality and/or interesting and inventive. Too Short's (?) "Wish I was a little bit taller" from some years back was really cute. I am wrong to lump all rap with gangster rap. Fact is I hate that SH*T so much that it erodes my ability to be objective about rap in general. Talking about abusing women,shooting cops, etc turns me off SOOOOOOOOOOOOOOOOO much that I do tend to lump it all together. And then when you see these tiny little kids doing it, well I just hate the whole scene. Rule #1 - To receive a recording contract one should be able to play an instrument or sing. That will ALWAYS hold with me. So I'll stop acting like I'm being objective.:) > i must agree with Lanny. some rappers are very creative, expressive, > articulate observers of comtemporary urban life. Fershizzle!! > > i must agree with Lanny. some rappers are very creative, expressive, > > articulate observers of comtemporary urban life. > > Fershizzle!! Aw, it's really more like "So what?" But then, I don't think Seinfeld is worth watching, either, for much the same reason. It's just not a culture (and NYC not a place) in which I'm interested. SignatureLanny Chambers, St. Louis, USA '94C the alignment page: http://www.hummingbirds.net/alignment.html >>>i must agree with Lanny. some rappers are very creative, expressive, >>>articulate observers of comtemporary urban life. >> >>Fershizzle!! > > Aw, it's really more like "So what?" It was a joke, Lanny. Dana > As for car radios, I think everyone must know by now that I don't even > know if mine works, since the only part of it I ever use is the clock. > Since my living room contains a high-resolution audio system worth about > 4X the current value of my Miata, to me any car stereo is just a toy. > It's the last thing in the world on which I'd waste any money or time. Somehow, I'm reminded of Steve Martin saying "moon-knock, uh, I mean, moon-rock needle. It's OK for the car, wouldn't want it in the house" ;-) In my original post where I said people were being brainwashed in to thinking bass was supposed to sound boomy, I was referring to the quality of the sound. No comment was intended toward any particular style of music. The BOSE system in my Miata is an equal opportunity distorter. >> Gotta disagree, much of todays kids music relies totally on these hugely >> exagerated bass riffs. Kids that grow up on this crap (not because of the [quoted text clipped - 25 lines] > >-John > In my original post where I said people were being brainwashed in to > thinking bass was supposed to sound boomy, I was referring to the > quality of the sound. No comment was intended toward any particular > style of music. The BOSE system in my Miata is an equal opportunity > distorter. Yes, that was perfectly clear. I still don't think brainwashing has anything to do with it, rather a preference to feel the vibration. If a person has boomy speakers then it will sound boomy, but still provide the desired bass sensation. MLB's comments (after yours) mix a dislike for "pseudo musical crap" with overemphasized bass. -John > In my original post where I said people were being brainwashed in to > thinking bass was supposed to sound boomy, I was referring to the > quality of the sound. No comment was intended toward any particular > style of music. The BOSE system in my Miata is an equal opportunity > distorter. That was also my original intent. It morphed into a discussion of raps "worthiness". The idea was that if they crank the bass to max, ANY music is going to sound totally unbalanced. To me. In my original post where I said people were being brainwashed in to thinking bass was supposed to sound boomy, I was referring to the quality of the sound. No comment was intended toward any particular style of music. The BOSE system in my Miata is an equal opportunity distorter. >> Gotta disagree, much of todays kids music relies totally on these hugely >> exagerated bass riffs. Kids that grow up on this crap (not because of the [quoted text clipped - 25 lines] > >-John You forgot about the mechanical coupling effect of the speaker and it's surroundings. The only way to settle such things is to actually measure them. (Been there, done that!). Don't forget the wiring size and length from the speaker to the amp. >I don't know how the "1/2 ohm theory" originated. I have seen it floating > around the internet in other places. The statement is incorrect. The [quoted text clipped - 46 lines] >> >If one or both speakers fail again I will replace them with a couple of >> >JBLs. I can get a pair for what one Bose replacement costs. Mechanical coupling and wiring size and length has nothing to do with rated speaker impedance. The impedance of the speaker is determined by the electrical properties of the voice coil. It is the alternating current resistance. What you are describing is the amplifier load impedance, which is a different issue. > You forgot about the mechanical coupling effect of the speaker and it's > surroundings. The only way to settle such things is to actually measure [quoted text clipped - 56 lines] > Checked by AVG anti-virus system (http://www.grisoft.com). > Version: 6.0.715 / Virus Database: 471 - Release Date: 7/4/2004 I beg to differ. There are "specs" and real world measurements. The standard way to test speaker impedance and overall performance involves use of a closed and open box, along with an audio signal generator and a resistive network, part of which is adjustable. The speaker cone may also have weight attached. A good A/C voltmeter, once referred to as a VTVM, (now usually an true RMS voltmeter with DB scales) is used to make most of the electrical measurements. A sound level meter can also be used for sensitivity and flatness measurements. Speaker impedance is a combination of electrical and mechanical characteristics, since all change the flow of energy thru the circuit. The same measurements are made with the speaker installed in the enclosure and location that it will be used. You can bet that this was done using a Miata and a fairly complex sound measurement system. Speaker impedance varies with the frequency and the environment. (Been there, measured that, done that!) The amp output characteristics can have a large or small effect. At one time the output impedance of an amp was determined by a transformer. Later, it was fashionable to provide large damping factors. Then very low amp output impedance. The real problem in a car is simply that 13 volts DC or so is not enough by itself to provide the necessary energy to drive a four or eight ohm speaker to high volume levels. It's much simpler to reduce the speaker impedance, thus not only reducing the voltage needed, but also reducing the difference between the amp and speaker impedance. > Mechanical coupling and wiring size and length has nothing to do with > rated [quoted text clipped - 81 lines] >> Checked by AVG anti-virus system (http://www.grisoft.com). >> Version: 6.0.715 / Virus Database: 471 - Release Date: 7/4/2004 Chuck, You are correct in most of your comments. If you would have carefully read my postings from the beginning you would see that we don't disagree on much. I misunderstood your use of the phrase, "mechanical coupling" as you mentioned wiring size and length. They affect the damping factor, but have nothing to do with the impedance of the speaker. They do affect the load impedance seen by the amplifier. Your statement that an output transformer was used to determine the output impedance of an amplifier is a half-truth. The transformer was used to match the impedance of the amplifier output to the speaker. Example: If the output impedance of a vacuum tube amplifier was 10k ohms, it was necessary to use a 250:1 step down ratio to match an 8 ohm speaker. Better systems used multiple output taps to allow correct impedance matching. The output impedance of most modern solid state amplifiers is determined by the output current limiting device (resistor), the minimum on-resistance of the output device(s), and the power supply capacitors. Many of the modern power amplifiers have output impedances of less than .1 ohms. Output efficiency decreases rapidly when the low impedance is reduced below a factor of 10. This would be at 1 ohms load for a .1 ohm amplifier. The Bose door speaker impedance is not unusually low. The basic impedance is determined by the inductance and resistance of the voice coil. The inductance calculates out to about 217 microhenries. The DC resistance is about .5 ohms. The impedance of the speaker/door enclosure combination never goes very low because of the speaker system resonance. The speaker impedance rapidly rises below 30 hz. Yes, speaker and design performance has been a topic of arguments since the beginnings of electronic sound reproduction. Jason Cuadra has done a good job of graphing the overall frequency response of the Miata Bose System. A grahic equalizer that offers + or - 15 db would be enough to straighten out the system reponse curve. A replacement door speaker with average or better mid range response would require less equalization. This would not fix the door resonance which gives the system a boomy sound. There is an assumption that the Bose system uses 12 or 13 volts directly on the output devices. It is possible, but unlikely. Better systems use DC to DC conversion to step the voltage up for higher wattage output with less distortion. > I beg to differ. There are "specs" and real world measurements. The standard > way to test speaker impedance and overall performance involves use of a [quoted text clipped - 110 lines] > Checked by AVG anti-virus system (http://www.grisoft.com). > Version: 6.0.719 / Virus Database: 475 - Release Date: 7/12/2004 So, other than replacing the speakers, it seems like this is an ideal application of a parametric equalizer between the tuner head and the Bose amplifiers. Has anyone else considered/tried this ? Cheers, Dana I have not heard of anyone doing it. Anything that would flatten the response curve would improve the sound. I also wonder about using something to deaden the door resonance. Maybe a foam or undercoating spray would work. > So, other than replacing the speakers, it seems like > this is an ideal application of a parametric equalizer [quoted text clipped - 3 lines] > Cheers, > Dana Bose supposedly built their idea of an equalizer into the head unit. > So, other than replacing the speakers, it seems like > this is an ideal application of a parametric equalizer [quoted text clipped - 3 lines] > Cheers, > Dana > Bose supposedly built their idea of an equalizer into the head unit. Of course. We're talking about "enhancing" their idea of an equalizer... >>So, other than replacing the speakers, it seems like >>this is an ideal application of a parametric equalizer >>between the tuner head and the Bose amplifiers. Has >>anyone else considered/tried this ? |
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