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PostSubject: Re: The Home Audio thread   Thu Apr 26, 2012 2:22 pm

Quote :
And some 8 inch drivers would probably be as loud as that lms ultra 5400 under the same wattage because of mechanical resistance of the woofer I'm thinking. Big time wattage woofers have lower SPL sensitivity and efficiency overall, and those certain drivers will take a mass of wattage to move properly, but this defeats the point of our conversation. I'mjust saying sometimes other factors out play diaphragm diameter :p
Yes, you can take the lightest, highest efficiency 8" you can find, and put it up against the heaviest, least efficient 18" out there, and the 8" might play louder in the higher band, but it will not outperform the 18" at true subwoofer duty. In the lower octaves, the big 18" will still trump the 8". Regardless, this is not a fair comparison. Take different size drivers of the same family, where materials are consistent, and the results are clear: the 18" will always play louder and lower, period.

The biggest advantage some smaller sub drivers have nowadays is their ability to take more power and use it to provide longer excursions. Subs like the 8W7 are said to be louder than other 12" subs, and that's true, but they need to use extra power to be louder compared to the 12". And there are always going to be bigger subs that can handle even more power, and offer more stroke. Ultimately, these bigger subs will be louder watt for watt, and louder overall.

There was a trend in SPL competition for a few years to use smaller subs. The simple reason was, when square cones were introduced, you could fit more cone area on a wall than with larger round cones. More cone area = more SPL. Same principle.

The way you've described, it doesn't sound like the servo is doing anything for you right now. The way this worked - the music signal was fed to the amp. The amp bumped the power and drove the cone according to the music signal. Of course, speakers are not perfect at replicating the wave form, so the accelerometer monitored the cone's actual movement and a small circuit (computer) compared the feedback from the cone to the actual music signal. The difference is deemed distortion, and the idea was to create a counter signal (opposite the distortion) to re-introduce back into the amp's input. In other words, "anti-distortion" was fed back into the stream to correct the cone distortion. As I've read, it worked very well, and helped Velodyne become a major player in the subwoofer market.

Keep in mind, the servo technology is only doing work when SPL increases to the point where the cone movement becomes non-linear. Probably somewhere above .75" peak-to-peak excursion. Below that, the voice coil is reproducing the waveform accurately, and doesn't need any correction from the servo.

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PostSubject: Re: The Home Audio thread   Thu Apr 26, 2012 5:55 pm

That sounds about right. I was told it works somewhat like noise cancellation Technology actually.

And also true with the woofer size. I was just saying some 8 inch woofers can actually be louder with 25 watts than some 18 inch woofers, but past 200 watts and high wattage systems, forget it. I've bypassed the servo entirely, and the 25 watts has nowhere near enough power to move the diaphragm past distortion from the original waveform either way :p



perfect example:

this 8 inch subwoofer has an efficiency of about 83db. there are 6 inch drivers that will make 25 watts sound louder on the lower end, because of the mechanical resistance required to push the wooffer.

this is a null and void point in my case though, because the paper velodyne woofer is extremely light while still mainting a large surface area.

http://www.parts-express.com/pe/showdetl.cfm?Partnumber=295-475

http://www.parts-express.com/pe/showdetl.cfm?Partnumber=292-2524

but, getting an 18 inch driver capable of under 20Hz is NOT cheap, and as you can see, the Pyle (I like to say pile of crap) driver is intended for PA use, not actual subwoofer duty.

furthermore, getting a quality PAPER driver indended for subwoofer duty is even MORESO no easy to find, or cheap, and once you start getting on the level of the TC sounds LMS ultra 5400, ore Maelstorm 18 inch sub, or Celestian, or Velodyne subs, it starts costing THOUSANDS to get a nice pre built sub.

Then again the TC is just a driver, but probably one of the best 18 inch sub drivers ever made for sound quality.

If I can't fix my Servo controller, I'm going to get a nice 1000 watt plate amp for it, and refinish my sub cabinet, and tune it sothat max volume doesn't clip the sub. my driver being 10 ohms would need more than a 500 watt standard amp to give me 400 watts RMS @ 10 ohms. I may even rip out some of the components of the Velodyne amp in a later project of building my own. it has extremely high build quality. I was shocked earlier to rip out a 4700uF Rubicon capacitor from some crappy sony speaker system I ripped apart for it's transformer, and it even had nice diodes in it! :O

[img(360px,270px]http://img585.imageshack.us/img585/8674/20120417224438.jpg[/img]

Here's the part I tried to fix





Look at that build quality, and the size of that toroidal transformer! :o Seems almost too big for only 400 watts razz



That black RCA input is the Servo connection that connects the acclerometer to the amp servo circuit in the external amp, it's easy to just bypass it with a regular amp. for a while, on the Velodyne amp, the servo stopped working, with the servo light on for some reason, but it still amplified signal fine. Just wish it worked like it was supposed to :3
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PostSubject: Re: The Home Audio thread   Fri Apr 27, 2012 12:33 am

Also, a while ago, one of my Alpine subs acted like it was blown out of nowhere, but still kind of worked. I tossed $50 on creigslist for the exact same driver with the bare kevlar showing in black NIB, but it sounds like a blown voice coil, and acts somewhat like one, when you push on it, but how could the impedance possibly be exactly 4 ohms if I blew the coil?






I carefully peeled up the rubber surround, but the knife here was starting to destroy the spider before it would pry off, so before actually harming it, I decided a different approach.
Is there any type of easily accessible solvent that will dissolve the glue on the spider? I'd like to take a look at the coil itself before scrapping this driver. it's a nice driver, and I could throw together a quick box for it and either sell it on craigslist, or make a nice little home sub out of it with a plate amp, and sell that or keep it. obviously it's garbage compared to my Velodyne, but it's a lot better than what the average person has as their subs, so I wouldn't mind fixing it.

edit:

would baking it in the oven at slightly under 200 degrees or 215 or so melt the glue, like it did for my eclipse headlights? and is it safe to bake a ferrite magnet? The spider is made of Nomex, which is used for firefighter suits, and nascar gear to protect against fires, so I doubt the heat will burn anything in the speaker

edit:



I'm pretty sure either heat, or mechanical movement of the woofer caused the glue to unseat and make the glue line un even on the diaphram connecting to the voice coil. no idea if you can see it, but the glue line is now uneven. this would cause the voice coil to rub, I put nail polish remover on the glue line of the Nomex spider, and I'm leetting it disolve now, no idea if it will work since last time I did this at my friend's shop, I was using special speaker glue solvent, and special cement they had to fix my Advent tower speakers :3

Edit:

UPDATE:



Nail polish remover seemed to barely work, and if this nomex spider wasn't so damn strong, I'd have ripped the hell out of it.

one thing I don't get: why the hell is a garbage 250 watt RMS Alpine type E Kevlar reinforced pulp cone woofer using a dual nomex spider suspension system? This is never implemented in such a low power, low end driver as far as Iv'e seen, and makes it a pain in my ass :[

Edit:

Update again, I can't get the bottom spider to come off with the nail polish remover, I had to set it aside before I got pissed enough to throw it out the window, but I'll try my soldering iron with exacto knife attachment in a while and see if that works.


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PostSubject: Re: The Home Audio thread   Fri Apr 27, 2012 8:12 am

Oh yeah, and this is my crappy home theater setup for right now. The Sony 55" rear projection LCD with 3 LCD panels is big, clunky, fuzzy with only 720p, dull and has crap black levels, needs a new bulb, which I overhauled by making the mirror in the lamp look brand new to bend the light properly. Its about 5 times brighter than when I got it, but still dull.



As crappy as this TV is, after calibrating it to my professional IPS panel studio monitor, the colors are better than any "LED TV" you will ever see. LED TVs are a complete market scam, and a lie. They are no closer to being an LED TV than this rear projection LCD. Its just an LED back light, with garbage TN panels.

Plasma is the way to go under 72 inches. Any bigger and you'd want a DLP.

If I ever spent big money on a big screen, the only TV I'd ever get is the Pioneer Kuro, which has better black levels than any plasma ever made and was made in 2008. This is because of sodium oxide I think, sprayed in the plasma filiments, which pretty much eliminated adjacent sub pixel light bleeding. My friend has a $12,000 Runco, which looks amazing, but the Kuro would still rape it.

But yeah, there's only one advent tower because I let my friend borrow them and he blew my woofer :[ the receiver is a garbage Yamaha 5.1 receiver 110 Watts per channel using SPDIF from my computer using my Auzentech X-FI home theater HD sound card as my surround sound processor, with toslink cable from the cable box, and HDMI pass through from the blue ray set to listen to all devices audio pass through on default audio device, so my computer pretty much is the receiver. The Yamaha has about 0.07% THD I believe. Video from computer is HDMI out from the ATI 6970 to The TV using the high end sound card as audio device. Sub out is fed to my little amp I built driving the Velodyje ULD 18 which is a 5.7 cut ft sealed box, 400 watt rms 18 inch driver foam/rubber surround and tar reinforced pulp diaphragm. Servo doesn't work.

Obviously my setup is pretty crappy but I'm not very rich, so its whatever. TV will die soon without a new bulb.
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PostSubject: Re: The Home Audio thread   Fri Apr 27, 2012 9:47 am

You'll never actually hear .07% THD with your ears. If the Yamaha amp sounds good (be objective), use it.

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PostSubject: Re: The Home Audio thread   Fri Apr 27, 2012 11:40 am

Well the real reason I got it is because I got it for about $50 and needed a home theater receiver for now, and can use it for diagnostics down the road, and I noted the THD was within my spec, and that it was powerful enough to use
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PostSubject: Re: The Home Audio thread   Fri Apr 27, 2012 1:22 pm

I wouldn't call it garbage though, just because it was found cheaply. Many
'better' high-end amps have higher THD specs, and they still sound good. More expensive tube amps rely on their higher distortion for the perceived "warmth" that buyers want.

Same is true of subwoofers, too. Many listeners respond to sonic characteristics based on materials, parameters, etc. ("punch", "kick", "boom"). Actually, the sub is just a piston designed to move air, nothing else. When true low-distortion subs for cars were introduced about 10 years ago, they didn't sell that well, because they didn't sound like many existing brands customers were used to - which regularly operated at above 10% THD.

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PostSubject: Re: The Home Audio thread   Fri Apr 27, 2012 1:27 pm

Yeah but tube amps have some of the most.linear sound out of any amplification. My friends McIntosh tube amps driving his Gallo 3.1 system sound better than almost anything I've ever heard. Transistor amps will.usually have a slightly artificial waveform no matter how low the THD spec is. And the thing is with these popular subs, the distortion makes me cringe. I can even hear it in my Alpines. I like musical, clean bass, not distorted bass that does nothing but vibrate your skull. And a brand that comes into mind is Memphis audio, kicker, Pyle, Sony explod, dual, many other brands have distortion and people think they sound good. My friend's 10 inch Kenwood in his hatchback sound almost as loud as my alpines, but there's so much distortion it sounds really bad. One reason I like my paper (Kevlar reinforced) cones is less distortion.
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PostSubject: Re: The Home Audio thread   Fri Apr 27, 2012 1:41 pm

My understanding is tube amps sound linear to a point, then gradually overload into distortion. This gradual overload is what makes tube sound desirable for most. The gradual onset characteristic is perceived as "warmth", but really it's slight distortion.

Solid state amps are just as linear up to their max, but the distortion comes on suddenly as full clipping. This immediate overload is not pleasing to the ears, and so is perceived as lower quality sound.

Most or all quality solid state amps sold today are A or AB class, and really do sound as linear as the tube amps (lab tests prove this). The only difference is, solid state amps keep the linear operation as power increases, instead of distorting like tubes. Just as most people prefer light distortion from speakers, they prefer it from amps, which is why we have a tube following. The very best Class-A solid state amps are actually more linear than their tube equivalents.

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PostSubject: Re: The Home Audio thread   Fri Apr 27, 2012 1:56 pm

Hmm, I guess that would make sense, but class AB amps have a cross circuit problem at high output I believe which makes a square waveform, and class A amps have inefficiency/heat problem. I'd rather have a slight distortion at High output than overheating issues, or clipping, but to that degree, I guess you are right. I think they also have class D amps with insane amount of filtering like 10 grand or more that is supposed to sound as good as class a without the cross circuit problem, keeping high efficiency and low heat.

My friends dad was supposed to help me build a Quad 405 amp with 5 channels to hook up to a surround sound processor before I moved from DC. It has some pretty good class a amplification but a bad stereophile review lol.

Tube amps are much less seceptible to EM interference as well, which is why the military uses them (nuclear bomb zones and whatnot) I guess.

But, the distortion should be different in tube vs transistor, with the waveform, right?
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PostSubject: Re: The Home Audio thread   Thu May 03, 2012 6:41 pm

I forgot how much I loved metal :3

https://www.youtube.com/watch?v=dqw2WAcv8Tw

You might hate metal, but this is my GO TO SONG to see if the subwoofer is musical enough for my tastes. within seconds, I can instantly tell when the diaphram of the sub driver has to exhibit too much excursion and the spider retention mechanism can't make the diaphragm recover in time for the next part of the waveform duty entitled to the subwoofer, hard to explain, but most 12" drivers, even ones with high bass, that will viibrate my skull, like my Kevlar Alpines, are still off on this song, making it sound like garbage. This is why I like quality bass, and people tell me I'm tripping for hearing the beats off, and I tell them "dude, the sub is slamming at THE WRONG TIME" they don't get it =[

https://www.youtube.com/watch?v=7vpuW5WWwVM

Also awesome quality for testing a sound system.

Jack Johnson is also great on CD or as a Flac.

I'm surprised people haven't been recommending material to test a sound system with :3
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PostSubject: Re: The Home Audio thread   Fri May 04, 2012 12:44 am

Quote :
Tube amps are much less seceptible to EM interference as well, which is why the military uses them (nuclear bomb zones and whatnot) I guess.

But, the distortion should be different in tube vs transistor, with the waveform, right?
Depends on what you mean by "less susceptible". It you mean tubes are less likely to pick up EMI as static, than I don't believe that. I noticed my old CRT television, essentially a giant vacuum tube, was a magnet for interference when the vacuum cleaner or microwave was on. But I have never experienced audible EMI in any solid state amp I've used.

I think the reason the military uses tubes is because they are hard to damage from EMP, which for the public isn't really an issue. How often to we experience EMI at a level were transistor gates would flow unexpectedly or fail? Also, do we really care about this in an audio power amplifier? Many a transistor radio that has existed 50-60 years without succumbing to strong EMI.

Think about how reliable silicon chips must be in order to power millions of CPUs and RAM boards around the world - consistently, billions of times per second. This wouldn't be possible with tubes, because they're big, run hot, less efficient, more expensive, and generally more fragile than transistors in every way except the EMP example. The question needs to be asked again: is EMP resilience really a good reason to use tubes in a power amp? The obvious answer is "no", and here are three more reasons: 1) Tubes are less efficient, creating less power per watt, 2) Tubes run hotter and have a shorter life under normal operation, 3) Tubes are more expensive, bigger, and heavier. The only reason people still buy them is nostalgia, and the fact that the warm, fuzzy sound of gradual onset distortion is just cool for some.

Yes, distortion is different with tubes than solid state, but watt for watt, transistors will produce more clean power than tubes. This is why ultra-hi-fi collectors love their giant, horn speakers that can crank out 105 dB at one 1W power - so their 15W class-A tube amp will actually sound good, because it isn't overloading. But I can do the same thing with a 500 W quality solid state amp and a set of drivers in conventional arrangement. The difference is, the tube set-up will take up half the room it's in, and will need some maintenance over the years. It will also cost a fortune. The solid state set-up will be almost invisible in the room, will be maintenance free for 50 years or more, and cost very little compared to tubes. The solid state will also play louder with less THD, even though it will clip eventually. My opinion: if you don't like clipping, buy a more powerful solid state amp. It's still cheaper than any audiophile grade tube amp.

On the other hand, if you just want to have tubes to watch them glow (the reason I bought a small tube amp), or you like the cool distortion they make as a guitar amp, go with tubes! They're cool! They're a conversation piece. But they don't actually sound any better than a good solid state, unless you like distortion.

Quote :
You might hate metal, but this is my GO TO SONG to see if the subwoofer is musical enough for my tastes. within seconds, I can instantly tell when the diaphram of the sub driver has to exhibit too much excursion and the spider retention mechanism can't make the diaphragm recover in time for the next part of the waveform duty entitled to the subwoofer
My go to tracks for bass testing are sine waves bursts with an SPL meter. Once I play all tones from 300 Hz down the 5 Hz at max listening level, I can make some deductions about my system's capabilities, like: what is the -3dB point of the system. Where are the power limits? Can response peaks and valleys be equalized? Where is the best crossover point to blend with the mid-range? What are the best cut-off slopes to use? Are there any resonance-induced vibrations? Can the bass be localized?

When all of these concerns are dealt with objectively, the system is now tuned. Now I can put in a hard metal track (or a clean jazz beat) and enjoy the music from a subjective standpoint. And it all magically sounds good, because the system is unbiased. The bass is clean at any frequency because it has previously been sculpted to be flat. Not loud enough? Not 'hard' enough? Well then, the studio engineers must have wanted it that way.

Suggestions for subwoofer testing: http://rivperformance.editboard.com/t2935-very-high-bass-songs

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PostSubject: Re: The Home Audio thread   Fri May 04, 2012 12:52 am

Interesting point with the tubes. I wonder how the audio distortion would actually be affected,I don't have an SPL meter, and I won't trust a phone app frown

but still that SPL meter wouldn't be able to measure the acuracy of when a bass note hits, or the overall sound quality of a system. THD doesn't even measure true sound quality, sadly. much more expesnive equipment is needed for that razz

but, doing it by ear can make it sound pretty damn good! and thanks for the link by the way
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PostSubject: Re: The Home Audio thread   Fri May 04, 2012 1:09 am

I use my ears for metering distortion - if it sounds bad, compressed, or just different, either better speakers are needed, or more power, or maybe both. Also, maybe the output level is high enough that the system's limits are higher than what I need to be listening at!

Machines can detect distortion, but ears are the best gauge for ultimate quality. They sometimes can be fooled though on SPL, so I use a meter for help. It's nice to see the needle stay within a 2 dB range as the sine sweep drops.

If you want to learn about tubes vs. transistors, without spending time and money buying and listening to both, check this guy out: Rod Elliot from the land down under. He is absolutely the best resource I know of on just about everything audio. Just on tubes alone, he has written a fountain of information, all of which I am confident is true. Unlike you and I, Rod has all the fancy equipment for measuring distortion and analyzing the quality of sound. I can (and have) read his site for hours at a time. I've been visiting his sight since about 2003, so much of my life has been wasted thus far learning different perspectives - knowledge that has resulted in many purchases, and much savings from avoiding unnecessary ones!

Hope you get something from it. I was most surprised to read about Single-Ended Triode (SET) tube amps, praised by audiophiles and selling for thousands of dollars - actually these are just distortion in a black box. Also interesting is the history of tube-amp phenomena, and how it actually caught on.

Link: http://sound.westhost.com/valves/index.html


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PostSubject: Re: The Home Audio thread   Fri Jun 22, 2012 11:51 pm

Something fun I've been working on in the past few days is converting an old broken Bowers and Wilkins subwoofer into a little creation using some sub drivers I had laying around. The little 6" B&W driver is actually really nice for a little thing, but I want MOAR!!!! happy



http://www.pioneerelectronics.com/PUSA/Car/Subwoofers/Shallow+Mount/TS-SW251


I got two of these babies for free a while back and had nothing to do with them (or really the time) until now. I decided to make a 400 watt RMS, 1600 watt peak dual 10" 2ohm sealed passive sub box at about 1cu ft. Ofcourse I could build my own box, but I don't have access to a table saw right now to make perfect cuts, and I do NOT want to do the straight edge cutting with my Jigsaw, or my dremel, however making some 9 inch circles with the dremel is cake smile

No pics yet but I'll update, and I'm not sure how good it will sound, but two 10 inch drivers pushing 89db with super stiff fiberglass woofers, and a special composite woven foam hybrid surround.. I'm hoping for some deep frequency response, and accuracy here. I want to put it ultimately right under my center channel for a 5.2 setup razz

Another great use for it is testing car amplifiers, because of how small and portable it will be.

Edit: I just realized, since both woofers can't be mounted on any side opposite each other, either one is going to be a passive radiator for a while, orr....


I could wire the other voice coil backwords, and it will not cancel out the other woofer, while one pushes, the other will pull, and it will be like having two subs on the same side, correct? I've never looked into that, and completely had a mental block building this thing, and the size of the cabinet would't allow any other placement of the woofer


actually, let me know if wiring one woofer backwords and the other regular won't work, because theres a messed 12 inch sub I have with a burned coil that I can saw the magnet off of and turn into a straight up passive radiator for the 10" woofer, which would work too, but I see no reason as to why my theory wouldn't work, because it'd simply be an active radiator, right? A passive radiator will push out the same exact way as wiring the other woofer backwords, making the total surface area greater, just making the radiator have an amplified source instead of being driven by the active woofer?

I'm pretty sure I'll be okay wiring the secondary woofer in phase, they are literally centered perfectly on opposite sides of a sealed box
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PostSubject: Re: The Home Audio thread   Sat Jun 23, 2012 12:43 am

If you wire one driver out of phase, it will acoustically cancel the other driver (no sound). A passive radiator works on the same principle as a vent, delaying the rear energy of the driver to reinforce the sound coming from the front side. Radiator tuning is determined by the volume of the box, compliance of the radiator, and the mass of the cone.

Try wring both drivers in correct phase and see how it sounds.

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PostSubject: Re: The Home Audio thread   Sat Jun 23, 2012 5:11 am

AA wrote:
If you wire one driver out of phase, it will acoustically cancel the other driver (no sound). A passive radiator works on the same principle as a vent, delaying the rear energy of the driver to reinforce the sound coming from the front side. Radiator tuning is determined by the volume of the box, compliance of the radiator, and the mass of the cone.

Try wring both drivers in correct phase and see how it sounds.

Normally, yes wiring one woofer in phase would cancel the other out, unless you're using a setup where wiring normally would naturally phase each woofer out? This way when the main woofer on the left (wired normal) will push in, while the secondary woofer on the right (wired in phase on a 2 ohm load total) will push out, making effectively one big woofer, or acting as if they are normal on the same side?



I'll update pics later, but that's what my setup looks like, I turned the porthole into a terminal plate as seen here to make it a nice sealed box within the both driver parameters combined. This would be wiring both subs at a 2ohm load, and wiring in phase like this would make the other woofer basically normal, given the woofer position, unless I'm missing something, because wired normally, these woofers are going to cancel each other out for sure.


on a side note:


as one of my Alpine sub drivers started slapping around, I thought the coice coil burned entirely (I think the amp was left halfway on a 2 ohm load into the 4 ohm driver, or settings from the 2 ohm load on both, and one of the VC inputs undid itself from hard cornering on backroads)

The varnish on the voicecoil was burned pretty badly, but the VC was still rock solid 4 ohms after I pulled out the cone and voicecoil. I put some Krylon fusion plastic clearcoat over it after cleaning it, and then I'll sand it smooth with around 2000 grit paper before trying to put it back in, but the glue on the voicecoil to the cone is actually lopsided.should I take it all apart and shave off the glue, then reglue it, or try melting the glue in an oven at like 170 degrees to try to reset the glue at the right angle to avoid woofer slapping this time? I'm going to put the woofer back in my buick if it's fixed 100% because my woofers right now are mismatched, so I'll refinish the paint coat on the poly coated surface (the diaphragms of the silver ones are Kevlar reinforced pulp cones with a poly finish coat, the kevlar is underneath)




A pic from a while ago shows my now mismatched woofer, the black one has the kevlar layer on the last layer this time, no poly. I'll probably make the black one a home audio subwoofer in a nice box eventually if I fix my broken Alpine.


Something interesting: for such garbage low end drivers, they seem to have very good build quality. They might only be 250 watts RMS and 750 peak each, but they have 89db efficiency, which is outstanding, and the cone material itself is awesome, so if the setup doesn't work out the way I like, I'm going to turn it into a Kevlar passive radiator, which will perform awesome smile

Funnily enough, the older, crappier silver looking models have a higher efficiency of 89db vs the 86db on that black kevlar woofer which I think is probably due to a heavier cone or voice coil but I could be wrong
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PostSubject: Re: The Home Audio thread   Sat Jun 23, 2012 8:59 am

If you're implying that the direction each driver is firing has something to do with its phase (bi-pole) that idea is flawed for low frequency duty. You can fire both of them up, down, left, right - or have them oppose each other, it doesn't matter, because bass is not directional. Phase is determined by difference in pressure between inside and outside the box. This is because the physical area of your baffles are not large enough to isolate each driver's output waves, which are actually larger than the box itself (40hz waves are measured in ft). If the box you were building were 10-20 ft high, then maybe the orientation of the drivers might come into play.

The best investment you can make as someone new to building enclosures is an order of used books on speaker design from amazon. Vance Dickason and Martin Collims are two authors who really changed my perspectives on this stuff. Take a week and put your nose in these books; you'll come out knowing more than than you ever will from trial and error experimenting.

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PostSubject: Re: The Home Audio thread   Sat Jun 23, 2012 9:43 am

Not a bad idea, and I didn't know the enclosure space needs to allow the length of the wavelength to cancel out the other woofer, meaning 80Hz needs to be 10 ft apart in the same box to cancel out the other woofer, because the wavelength of 80Hz is about 10 ft?

And, I thank you for the book references smile

if this is true, then it becomes much easier if I end up maessing with high end audio to solve phase issues from crossovers of higher frequencies with meters and calculations
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PostSubject: Re: The Home Audio thread   Sat Jun 23, 2012 11:05 am

And that's theoretically correct only if you have enough space to do it. Inside a car, the rules change because the waves dont have a chance to fully develop. That means everything is in terms of air pressure below a certain frequency. You can almost think of the cabin of the vehicle as a bandpass enclosure that you are inside. This is why popping the truck, or opening sunroof/windows often changes the sound quite a bit - you are in fact venting and tuning the "enclosure".

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'98 SC Riviera 281k miles 298 HP/370 TQ 0-60: 5.79s ET: 13.97 @ 99.28 4087 lb 20.1 avg MPG Nelson Ledges Lap: 1:30
3.4" pulley AL104 plugs 180 t-stat FWI w/K&N 1.9:1 rockers OR pushrods LS6 valve springs SLP headers ZZP fuel rails
KYB GR2 struts MaxAir shocks Addco sway bars UMI bushings GM STB Enkei 18" EV5s w/ Dunlop DZ101s F-body calipers
EBC bluestuff/Hawk HP plus SS lines Brembo slotted discs DHP tuned Aeroforce Hidden Hitch

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PostSubject: Re: The Home Audio thread   Mon Sep 03, 2012 9:52 pm

Just thought I'd post 'cause I dunno - it's cool

My grandmother just sold her weekend home that they built some years ago and gave me the audio system they've had there. The receiver is pretty awesome

It's a Technics SA-850
My dad used to go to Japan with some frequency for his old job at TDK and he picked it up there and brought it home for my grandfather. This thing is older than me. I love the way old electronics are built! This is from 1984 and it has maintained its condition better than my Aiwa AV-X120 receiver at 2 years old (much cheaper receiver but still).

Also got some pretty sweet older pioneer speakers but I'll have to grab them another time from the house because my car was full.
I waaant to say they're CS-705
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PostSubject: Re: The Home Audio thread   Tue Sep 04, 2012 12:10 pm

That's an awesome-looking piece, and I bet it sounds good, too. Plus there's the added significance of it being obtained overseas by your dad. I like how the cutting edge '80s stuff, especially Japanese products, are completely void of any curves. Maybe they'll throw in a perfect circular arc once in a while, but I don't see any on the piece you have. I actually think they started using sliders in place of dials just so they could make everything align to 90 angles!

I have a Sony shortwave radio at home that I'll try to dig up and share. It's straight out of the '80s, looks a lot like your Technics piece.

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'98 SC Riviera 281k miles 298 HP/370 TQ 0-60: 5.79s ET: 13.97 @ 99.28 4087 lb 20.1 avg MPG Nelson Ledges Lap: 1:30
3.4" pulley AL104 plugs 180 t-stat FWI w/K&N 1.9:1 rockers OR pushrods LS6 valve springs SLP headers ZZP fuel rails
KYB GR2 struts MaxAir shocks Addco sway bars UMI bushings GM STB Enkei 18" EV5s w/ Dunlop DZ101s F-body calipers
EBC bluestuff/Hawk HP plus SS lines Brembo slotted discs DHP tuned Aeroforce Hidden Hitch

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PostSubject: Re: The Home Audio thread   Sat Sep 15, 2012 9:15 pm



I love my studio monitors ^_^

Kevlar is an outstanding driver material, looks pretty, silk domes are so natural sounding unlike other tweeter materials happy



And here's my little center speaker for home theater use only. my computer sound card (Auzentech X-Fi Home Theater HD) is the pre outs to the amp with true high fidelity analogue surround sound capabilities. That $200 little speaker ball actually has a paper cone, and the voices sound extremely natural with it smile
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PostSubject: Re: The Home Audio thread   Fri Sep 28, 2012 11:44 am

The ongoing home theater endeavor just moved a step further. I've been slowly building this modest system for a few years now. Starting with a tube TV, rabbit ears, and DVD player (see page 4 & 5 of this thread), it's now gotten a bit smaller and simpler. Replacing the DVD idea is an Apple Mac Mini running Hulu, Front Row, and PLEX. Of course, our 200+ title movie and TV show collection is being moved to a 1.5TB Seagate drive unit that feeds the Mac. The drive is hidden in the cabinet, and so far holds about 80 films and 50 TV episodes.

We also took the liberty to mount the Sony 40" to the wall, finally!

Yes, this is still a 2.0 channel set-up. I'm not a surround sound guy, and the audio quality is surprising, even with no subwoofer. Video is now fed digitally through HDMI.



Using the Front Row app:



Hulu:



A couple of our remotes:



Of course, it's a computer too, so we can grab the bluetooth keyboard and trackpad to surf the web from the couch. I can also control everything from my iPhone with WI-FI using a $4 app called Rowmote, which works surprisingly well.



It's not the biggest or loudest system, but that's what we like about it. The hope is keep things super minimal and eventually sell the DVD collection. I have to say, so far I really like how it works. The Mini is blazing fast and the experience is seamless - it's a computer that doesn't act like a computer or look like one, and the PLEX interface really has that high-end home theater feel. Still learning exactly how it works!

PLEX:




_________________
'98 SC Riviera 281k miles 298 HP/370 TQ 0-60: 5.79s ET: 13.97 @ 99.28 4087 lb 20.1 avg MPG Nelson Ledges Lap: 1:30
3.4" pulley AL104 plugs 180 t-stat FWI w/K&N 1.9:1 rockers OR pushrods LS6 valve springs SLP headers ZZP fuel rails
KYB GR2 struts MaxAir shocks Addco sway bars UMI bushings GM STB Enkei 18" EV5s w/ Dunlop DZ101s F-body calipers
EBC bluestuff/Hawk HP plus SS lines Brembo slotted discs DHP tuned Aeroforce Hidden Hitch

^^^ SOLD ^^^ frown

'05 GTO 85k miles 0-60: 4.8s 16.9 avg MPG Nelson Ledges Lap: 1:26
Because fun


'70 Olds Ninety-Eight Holiday Coupe 116k miles 455 Rocket V8
Because cool


'95 Celica 152k miles 0-60: yes
Because free
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PostSubject: Re: The Home Audio thread   Fri Sep 28, 2012 1:29 pm

AA, Curious how you like Hulu Plus. What are it's major benefits over, say, Netflix?
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