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12v bicycle trailer sound system details

Discussion in 'Automotive Electronics' started by budget minded, Oct 2, 2016.

  1. budget minded

    budget minded Member

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    this isn't exactly an "automotive" etc. application, but it will be a 12 volt system, just lacking an alternator. there are a few issues i need to iron out though. it was originally supposed to be a 36v system, but that created a lot of problems eg. separate batteries for an EQ/crossover or using passive low pass inline filters which seemed to drive a lot of people nuts, and the dearth of 36v power meters amongst other issues.

    [​IMG]

    just now, i took the plunge on a Planet Audio BB1200.4 @ 4 channel amp for several reasons... it should be more rugged mounted under the trailer than the sure modules i originally intended to use, it can be configured as a 3 channel sub sat amp with built in crossovers, has level setting pots for both front and rear (sub) channels and the 18dB bass boost option will be especially useful when i start rolling with only a pair of 8 inch 96dB DJ speakers until i biamp with 4 x 12" subs. it's a very flexible amp that solves a lot of problems, is efficient class D, is reasonably light and compact, already has RCA inputs and probably beefier terminals than the little sures and i just like its clean simple lines, blue illuminated logo, and i like the tree hugger friendly brand name even if the amp will be out of sight.

    the DJ speakers are rated at 8 ohms, so i'm expecting lower than rated output, maybe 75wpc, on the mains, but that should be a very friendly load on the amp and was also planning on an 8 ohm load on the bridged mono sub channel, instead of going 2 ohm as i'm more concerned about SQ, run times and durability than SPLs.

    the issues i'm looking to resolve are wiring related.

    1. i'm planning on using a pair of 12v 35aH lead acid batteries in parallel for a 12v 70aH system. i planned on using a pair of positive and negative distribution blocks to link the two batteries and use a 70a+ circuit breaker as a power switch along with using an inline fuse, if necessary, to protect the amp, though it has its own fuses. would you recommend an inline fuse too, and if so, what amperage?

    2. i planned on creating terminals after the distribution blocks so that i could charge both batteries at the same time. are there any issues about doing that i should worry about, or special needs i'd have with a charger. i planned on trickle charging the system to give the batteries an easy load. i was going to have to create 3 individual terminal pairs at 1 for each battery along with 3 power meters when i was planning on a 36v system, but this seems to be the much easier route. the only issue i can imagine with parallel charging 2 batteries would be voltage balancing them as is done with battery packs.

    3. i plan on using a power meter, but read in one review that a user put a fuse on his meter. i planned on tapping into the circuit after the breaker so the meter is unpowered when everything is turned off. should i use a fuse for the meter too, and if so, what rating. they all seem to draw under 20 milliamps. i would think that a 1 amp load/fuse wouldn't fry a meter. down the road, pun intended, i also intend to add a 12v LED lighting circuit. i know the basics about needing resistors for LED circuits and could handle doing the calculations, but would i also need to fuse that too? one of the things i "learned" years ago is that regardless of how much current you have, a component/circuit can only pass as much current as the components allow, but since then have seen that overvolting an amp can fry it and i wonder if overamping can too.

    CORRECTION: i'll be using the 4 ohm and not the 8 ohm version as it's 4dB more efficient
    4. i'm planning on eventually using 4 Goldwood GW-12PC-4 12" woofers because they're the most efficient, especially at 30Hz woofers i could find for the 1.2 cubic feet, I THINK, sealed enclosures i intend to use. i did thiele small calculations on a bunch of mostly dayton & goldwood woofers, and the goldwoods had both the highest output at 30Hz by 9dB (!!!) compared to everything else in the enclosures as well as having a "perfect" system Q of .707 with hopefully extra tight bass from the small air spring.
    [​IMG]
    they're rated at 225w continuous at 4 ohms. i was planning on wiring them series/parallel to maintain a 4 ohm load. as i understand it, speakers in series can only take their individual rated output as they're in a "closed circuit", but if they're also wired in parallel, can't they split the power eg. 2 x 225w on a 400w amp?

    my understanding of electronics as far as circuits go is basic so i'd appreciate it if the experts here would correct any errors, if any, i'm about to make or add input on anything i've overlooked. thank you in advance for your time and consideration.
     
    Last edited: Oct 3, 2016
  2. budget minded

    budget minded Member

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    well, all of the debating i've done over the years in planning this system and others has driven home the idea that as many amp hours as possible are needed with high powered subs for run times over 10 minutes, so i was going with 70aH as that's about the highest capacity i can carry at 50 pounds not including everything else.

    i won't be using car batteries. in well over a dozen hours worth of looking for needles in a "can't sort by amp hours" haystack, these are the batteries i came up with.
    https://www.amazon.com/dp/B007Q2CUD0/ref=olp_product_details?_encoding=UTF8&me=
    [​IMG]
    48 pounds for 2 at 12v 35aH, compact enough to be vertically mounted under the trailer (horizontal gel cell$ would be preferable) at 7 1/2"W x 5"H x 6 1/4"D for about $120 for a pair with free shipping.

    i'm happy to hear that you think that much capacity is overkill. that should mean higher SPLs, longer run times, and less stress on the batteries. i'm only going the SLA route right now to get rolling ASAP. eventually, i'd like to lighten everything up with li-poly$, but don't have $300+ lying around collecting dust.

    the frequency response thing when speakers are in series is something i've never heard before. if that's the case, then it sounds like it'd be better to split the subs into 2 @ 4 ohm loads and run them "in stereo" at 200wpc instead of bridging. somewhere along the line i got the impression that it's better to double your amp's power than your number of channels which gives up the "free 3dB" from doubling the number of drivers at a given wattage, and i've never heard a discernible increase in output when connecting a second stereo channel with one already playing.

    i'd rather wire everything up whichever of those two ways is optimal, but NOT run all 4 woofers parallel at 2 ohms which has the potential to blow the amp or drive it into clipping and blow the speakers. i'll take whatever output i can get safely out of this system, but don't want to be greedy about it and stress the gear. i'm not SPL drag racing and this is just a bicycle system afterall, and even 10wpc bookshelf systems playing good music get people dancing in the streets, but a fairly serious system that's better than many cars really drives people nuts.

    i've ridden with this guy and his peeps once...
    [​IMG]
    at a mere 100wpc with 92dB efficient woofers (i still say have some backwave phase cancellation through opposing ports), people we passed ran into the streets dancing at stop lights and hung out of car windows grooving or honking their horns. we even had another cyclist with a cowbell join us. that system plays pretty cleanly at respectable volumes you can clearly hear a hundred or more feet away downtown with traffic.

    i'd already seen that system on youtube a couple years before moving here... small world, huh? and consider it a friendly rival, so for what i'll be lacking in internal volume, i'll be tossing another pair of drivers, higher efficiency AND higher power at 30Hz for a local bicycle "IASCA". that, and i think my taste in beats is better.

    for what it's worth, these 96dB @ 70-20kHz proels with 8" celestion woofers & titanium compression tweeters will be all i start with, possibly stereo bridging and definitely bass boosting until i get subs and try to plug their ports
    [​IMG]
    for PA speakers, they sound very nice if not fully hi-fi and i got an amazing deal on them at about $120 delivered when they list at 4 times that. i expect though that they'll sound even better on a class D amp than the cheap department store 20wpc (?) 30 year old technics receiver i broke them in with. they have a nice midrange in particular, but really need a bass boost.

    i also rode with a trailer system owner and his crowd before moving here, but did not like that guy at all. before riding, someone quoted the talking heads' life during wartime, ("this ain't no party, this ain't no disco") which i just happened to have with me on a CD, so i popped it into my little 10wpc @ 89dB with 5 1/4" woofers bookshelf system,
    [​IMG]
    and IMMEDIATELY, jealous d-bag goes over and powers his 12v subbed system up to drown me out with annoying soulless techno.
     
    Last edited: Oct 2, 2016
  3. budget minded

    budget minded Member

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    i didn't perform calculations, BUT, i've seen the volts x amps = watts formula a couple times, and using that, 12v x 70aH = 840 watts which translates to roughly 100w + 100w + 600w for the mains and subs in my system, so in theory should be correct, or even short of the 1,200 watt top rating at 2 ohms, which i won't be doing.

    for casual cruising, i probably won't even be pushing 100 watts total, but downtown on club nights, or at tailgate parties, i do intend to push the system to its limits.

    back to the series/parallel wiring issue, it can't be avoided if i'm going to give the amp a "safe" 4 ohm load as the 93dB goldwood woofers i want to use are 4 ohm only. the 8 ohm versions are rated at only 89dBw. i can't imagine that any EQ change from running 1 layer of speakers in series could be catastrophic considering that infinity had to have used that tech for their "line array" speakers from the 80s to maintain a usable impedance and i'm sure it's been done many times in "sweet sixteen" high efficiency systems.

    what i'm still not sure about is if two sets of speakers connected to an amp in parallel SPLIT the power between them. if an amp puts 2oo watts out, and you put a pair of speakers rated at 100w each on it in parallel, then does each speaker get only 100w of power?
     
    Last edited: Oct 5, 2016
  4. dave

    Dave New Member

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  5. budget minded

    budget minded Member

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    well that's EXACTLY what i'm after. this system will be used almost exclusively for playing dance music, so a "free" bass boost (probably more of a highs rolloff i imagine as there are no free meals, and increasing impedance should cause some sort of output loss) will be a good thing. a continuously variable crossover frequency as well as bass boost should also help compensate for woofer issues. to me, bass rolloff at the bottom octave would be minimized by any "highs" rolling off and flattening their response. i'm expecting to crossover at 70-80Hz as that's the f3 of my mains.

    UPDATE:
    just got my amp this morning. it's small, but surprisingly, it's heavy like a brick. i'm gessing it's because of heat sinking as it weighs more than my 5x100w panasonic sa-xr class D receiver which includes a power supply. it feels pretty solid. i checked a couple pawn shops for starter subs and found a little sealed 10" kicker for $45, but i'd like a larger 12" to move some air. most of the subs i saw were pairs over $100. i could buy a new pair of generic 12s and a box for that much.

    all i need to get rolling now is a charger and battery(ies).
     
    Last edited: Oct 9, 2016
  6. audioguru

    audioguru Well-Known Member Most Helpful Member

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    Hee, hee, hee!! Where in the world are there bicycles with very high power and very loud audio systems on them? Here we have cars and homes with them.

    The Planet Audio amplifier is missing detailed audio spec's like "Amount of continuous power per channel into 4 ohms or into 2 ohms at a certain low distortion (no clipping) over all audio frequencies from 20Hz to 20kHz, at a certain power supply voltage".
    The sales sheet says "RMS power into 4 ohms= 113W X 4" but the distortion, frequencies and power supply voltage are not said. Maybe 50W REAL WATTS per channel?
    The owner's manual says "peak power into 2 ohms= 300W" but RMS power is simply half at 150W. Maybe 66 REAL WATTS per channel?

    The minimum allowed speaker impedance per channel is 2 ohms which is two 4 ohm speakers in parallel or four 8 ohm speakers in parallel. When speakers are connected in parallel to this amplifier then the total power, distortion and battery current are increased.

    All four channels are already bridged. "Tri-mode" simply adds some of the rear left to some of the rear right to drive the subwoofer in mono. Then the rear speakers and subwoofer must not be less than 4 ohms. On a bicycle there is no "rear" so you can use the subwoofer tri-mode connections but without rear speakers then the subwoofer can be 2 ohms for a higher output power.
     
  7. budget minded

    budget minded Member

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    yeah... i'm EXPECTING some "overspecificationism" in a cheap amp. that's OK. i made sure to read reviews first, and even taking efficiency out of the question, i've been a class D fan since buying a sonic impact amp back when they were still $15, and love my panasonic sa-xr receiver and the extreme treble speed & control it offers on metallic percussion.

    THESE are the specs i found advertised
    • Max Power Rating:
      • 4 ohms: 200 watts x 4 chan. (i'm expecting half that at 8 ohms)
      • 2 ohms: 300 watts x 4 chan.
      • Bridged, 4 ohms: 600 watts x 2 chan. (again, expecting half that with 1 pair bridged)

    i just went with the planet audio because it was cheap, looks nice & especially because of all of the problems it solves with built in crossovers, the ability to biamp, and not having to deal with a "fussy" 36v+ system that would require another battery for signal processing. i've been sitting on these DJ speakers for months by now and want to get this system rolling before it's too cold to take it out. if i can only get 300w out for the sub(s) bridging the rear channels, that should be more than enough to get people's attention.

    i'm planning on giving the amp an 8 ohm mains load and a 4 ohm sub load. like i said, i don't want to be taxing the amp with 2 ohms even if it'll put more power out. if a simple 2x12@92dB system with just 100wpc can get loud enough to get people moving, then between my 96dB mains and four 12s driven with even more power, i'll have a nice enough system for my needs. in a future round of upgrades, i could even add a dedicated sub amp.

    bike systems aren't super common, in part because bikes themselves aren't. i want to have a nice system to fight back against "car culture". i will take great pleasure in making at least SOME car owners insanely jealous of my bike system, ESPECIALLY when they see it in action drawing crowds of dancers, and they aren't drawing anything with their crappy music.

    when it comes to bike stereos, women LOVE THEM! i've seen a sunbathing woman jump up and start dancing on a bike path when i had the saddlebag system above, a GORGEOUS hippy chick danced to it playing disco downtown until a hater got so jealous he started panhandling her until she went away, one woman INSISTED on giving me $5 one night for some reason, one woman wanted a trailer she could ride on because she liked my tunes and wanted to join me, and best reaction, a really busty MILF came up and freaked on my leg (basically dance humped it) downtown while i fought to keep my bike from tipping over once. i don't care what kind of car you have or the system installed in it, you just can't get that kind of play like you can on a bike.

    MOST bike systems though are crap. people just get a car battery and cobble together a system with loose wires, poorly cut plywood and lots of duct tape. i've seen some really nice looking installations on lowrider trikes and trailers, but so far, i haven't seen anyone build a sealed 4x12 SQ trailer system. when i eventually go fiberglass, there's a chance i might even go with EIGHT subs and use air motion tweeters.

    right now, i'm just working on a couple stages of system, first, just getting rolling with my DJ speakers and a bass boost, then adding a sub, maybe a ported 15 or whatever i can get a deal on in a pawn shop (though they tend to overvalue junk) for a cheap system. then, stage 3 would be either building a system with a pair of 2x12 boxes as i specifically bought this trailer for its 28"+ width between the wheels or going all out and building a 4 x 12 fiberglass system over the winter and including lighting. that's another good reason to go 12v... 12v power inverters are common and reasonably cheap. i'd like to get at least one LED disco light to really make the system stand out.

    i'm just so sick of having to listen to everyone else's crappy heavy metal/gangsta/techno/banda etc. tastes in music everywhere i go. i'm trying to fight back against the forces of "i can't dance to that crap" with upbeat funkier fare. as the scene i want doesn't exist, i have to create it myself. i've seen too that a lot of the nicest bike systems like to boom gangsta too. i've hated that crap since it ruined hip-hop around 1988.

    i was so effing annoyed when i lived in oregon and a club that played LOUSY wannabe gangsta music, to a crowd that would crap its pants if you ever dropped it off in a REAL hood, was looking for a DJ but wouldn't give me the chance to show them that people will ALWAYS appreciate positive funky beats like "pon de replay" or old school hip-hop, funk & disco. those sucker DJs are FIDIOTS! they only play tunes for their gangsta poser buddies and have no clue that LADIES tend to prefer softer fare, even easy listening. that's the whole point of a club, to get ladies dancing, even if wannabe gangsta fools can't dance.

    if you haven't heard of bike systems, then you haven't seen one of these over the top bikes from queens

    [​IMG]

    personally, i find such a system impractical between the rolling resistance of those tiny shopping cart training wheels and all of the weight that has to be hauled and the aesthetics that don't do it for me, but i bet it's loud.

    i used to chat with the owner of this UK system a few years back. it's probably the loudest trailer system (though i'm not a fan of ports & piezos myself) and a really nice install.

    [​IMG]
     
    Last edited: Oct 9, 2016
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  8. budget minded

    budget minded Member

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    recurring suggestions:
    yes, but NOT in the infrabass range. high efficiency woofers have much sharper rolloffs. that's why so many of them are only rated to 50-70Hz. i've already given that consideration, and come to the conclusion that regular woofers will have the same or even better outputs at 20Hz than pro units with less rolloff and an overall flatter response. high efficiency woofers only really make sense over 100Hz. that, and they're not at all friendly to smaller sealed enclosures creating high system Qs that resonate over 100Hz creating a boxy sound and selling out to one note bass port & phase etc. distortions and bass sluggishness for higher SPL ain't going to happen in any stereo i own ever if it can be avoided.

    SARCASM ALERT: (regarding using sealed instead of ported boxes)
    (banned there, done that) and i'm REALLY frosted that i couldn't even tell a mod to go eff himself for banning me for standing up for myself, and NOT and of the relentlessly instigating tag team trollboys, because might makes right and facts are for sissies. hey... finding SOME PLACE to get that long festering rage off my chest was a little cathartic. thank goodness no one here has trolled yet.

    i DESPISE bloated distortion inducing ports and get tired of having to throw facts at port lovers who don't want to hear them. if they like boom, that's their prerogative, but i DEMAND drums that thump cleanly and quickly. i'll trade rolloff for distortion every time. i can't wait to stuff the ports on my proels, but for now, i need as much bass as i can get from them.

    GREAT! already thought of that. so, YOU'RE BUYING then? sure, i'll take them and a $100 smart charger too. thanks for your $400+ generosity! :D like i said, i'll go that route down the road when i can afford it. now, i'm just scraping by and close to half a year behind schedule because of it with speakers and a trailer both collecting dust. if i had money to burn, i'd be doing a lot of things differently.
     
    Last edited: Oct 9, 2016
  9. audioguru

    audioguru Well-Known Member Most Helpful Member

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    The Planet Audio BB1200.4 amplifier:
    How much power per channel into 4 ohms at clipping? The sales sheet and the owner's manual do not say how much distortion, they say 113W RMS x 4 into 4 ohms which might be clipping like crazy with 30% distortion.
    Without saying how much distortion, the owner's manual says the total RMS power of all 4 channels is 900W RMS @ 2 ohms: 225W x 4 RMS @ 2 ohms, or is a total of 452W @ 4 ohms. The owner's manual says the bridged power is 450W x 2 RMS @ 4 ohms.
    Note that only 2 speakers are used when the amplifier is bridged.
    Therefore nobody knows how much power your speakers will get.
     

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  10. budget minded

    budget minded Member

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    there's no way i'm pushing my system into 30% distortion. i will limit my output to maximum CLEAN sound. this is to be a sound quality build after all. i'll be fine with whatever the system's max SPL is regardless. the more dB, the better, but i'm thinking of this as just a glorified boombox, and will be impressive enough because it's a bicycle system, and not a car one.

    back to woofer outputs, i grabbed a few graphs of high efficiency drivers, and like i said, they have terrible outputs at the bottom octave.

    this one is for a $75 celestion TF1220 which only puts 75dBW out at 20Hz, besides probably being optimized for a large ported enclosure.
    [​IMG]

    this $55 eminence alpha 12A puts out a piddly 68dBW at 20Hz
    [​IMG]
    but check the unbelievable (literally... i have a hard time believing this one speaker can miraculously outperform virtually every other speaker in the world for bass efficiency in a curve that's at least 2dB louder than its 93dB rating) curve out for the 93dBW $70 goldwood out!
    [​IMG]
    a whopping 88dBW at 20Hz! NOTHING i've found a graph for under $100 comes close, and like i said, it would have a perfect system Q of just under .7 in the 1.2 cubic foot sealed boxes i intend to use them with. to be honest, i have a hard time believing those woofers can be so efficient AND go so deep too. i have suspicions that maybe the weighting was toyed with or goldwood used some other trick to overspecify (ugh, i hate the sound of that word) them. virtually nowhere in the curve does the output dip down to the 93dB rating.

    here's the calculated output of the woofer in the boxes i intend to use

    [​IMG]

    when i performed the calculations, i think the next closest woofer was -9dB at 20 or 30Hz after factoring initial efficiency in. if there's another woofer that can put more out in a small sealed box and costs the same $70 or less, i'll be all over it. 9dB is like having 8 times the power at the lowest frequencies and then adding another 6dB from doubling the number of drivers twice will just improve efficiency that much more. i want a system capable of handling the infrasonics in woofer cooker when it isn't thumping dance beats.

    um, actually neither. i'm naturally suspicious of too good to be true claims and EXPECT manufacturers to overspeck (the way i prefer to say that) their gear, especially at the low end of the price scale. what convinced me to get the amp was the fact that it's class D which is my preferred tech as i like that "clinical sound" and reading reviews from people who've actually bought one.

    [​IMG]

    i'd already bought 4 hifonics subs from there based on positive reviews, and THOSE didn't disappoint (i still have one in a box in storage in another state i WISH i had right now), and the power acoustic amps i bought on closeout (specifically because of their very cool "plasma sphere" displays) were well reviewed and sounded excellent with a warm bottom and tons of enthusiastic toe tapping pace and overall ease PERFECT for a dance system, so i'm inclined to trust their review system which DOES give some products low scores.

    i'm convinced that the amp will give me nice enough clear & detailed sound with great woofer & tweeter control which is a class D trait in general, and put out enough power to play louder than the "loud bike" above and get people dancing. i'm not going to sweat losing 3-6dB or not being able to shatter concrete at 100 yards. the system's purpose is dancing within a 20 foot radius. i'm positive it will acquit itself admirably if not win a 150dB+ drag race. that's just not what i'm going for.

    this won't be the final version of the system either, it's just an amp to get started with using nothing but the proels to start and being able to compensate for their weak bass with a boost. it's a "here and now" system. as finances allow, i might run it stereo bridged for mains and get a better quality killowatt amp for subbing.

    i just can't afford a complete high end system yet. i'm doing what i can with what i have, and it looks like i won't even be able to get rolling with the starter system yet as i probably don't have enough for batteries, a charger AND cables, distribution blocks, fuses, a circuit breaker and hardware AND building the trailer and getting my bike rolling again too.

    this amp was a "big leap" for me financially. it's the best i can do for now. i'm in one of the worst job markets and have been jerked around almost 5 months on a physical so i can donate plasma besides just recently having to pay that storage unit over $100 in fees plus 3-4 months back rent after my bank changed my debit card and stopped paying my rent there.

    yes, i'd LOVE a molded carbon fiber, 144 spoke dayton wheeled, whitewall, li-poly powered system with dayton reference subs, air motion tweeters, wide range planar mids, mcintosh amps, disco lights, video screens, LED ground effects, & EL wire etc., but i live in the real world. LOL
     
    Last edited: Oct 9, 2016
  11. audioguru

    audioguru Well-Known Member Most Helpful Member

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    Did you notice that the 12" woofers you posted have a fairly high efficiency at mid frequencies and a fairly high free-air resonance frequency? Then in a sealed enclosure the resonance frequency is raised even higher and the deep bass output is low level. A woofer that is not as efficient but has a lower resonance frequency will produce louder deep bass in an enclosure that can be smaller.

    Bass boost throws away the efficiency of mid frequencies because it actually attenuates the mid frequencies so that the max amplifier power can be used for deep bass output. There is no "boost".
     
  12. budget minded

    budget minded Member

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    so, you're saying bass boost is REALLY a passive low pass filter that merely attenuates the HF then. not always though. on old receivers, bass boost circuits (aka loudness) WOULD raise the LF output, like an active EQ, and output would drop in bypass mode.
     
  13. audioguru

    audioguru Well-Known Member Most Helpful Member

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    What I mean is that the circuit does not boost the maximum power, instead it keeps the bass at or near maximum power then it turns down the levels of the mids and highs. It is easy to add gain or add an attenuator to a filter to create EQ.

    My stereo has a "bass boost" circuit that I designed and made. The speakers are sealed 8" woofers with a -3dB cutoff at 60Hz. My circuit boosts the bass +10dB at about 35Hz so that the 8" woofers sound like a subwoofer and you can feel very low frequencies. The amplifier has plenty of power and is never near full power so it works fine. +10dB is 10 times the power if actual boost is needed.

    A simple passive filter has a 6dB per octave slope that is not enough. A sealed speaker rolls off its bass at 12dB per octave and a ported enclosure roll off its bass at 18dB per octave so an active filter circuit is needed for these slopes.
     
  14. tcmtech

    tcmtech Well-Known Member Most Helpful Member

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    You called? :D

    You were banned over there for completely different reasons than you claim too. :rolleyes:

    Have fun with Audioguru. If you think I'm a hard nose just wait until you get him going with your nonsensical reasonings.:eek:
     
  15. budget minded

    budget minded Member

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    YEAH YEAH YEAH!!!! that's my idea of bass... lightning fast undistorted thumping!!! eff boom! i don' care how popular it is.

    even better though is a totally box free planar with even more rolloff like a magnepan. now THAT is super fast bass! i'd use maggies as subwoofers any day... pure speed & clarity without a hint of lag, blurring, resonance, or box colorations. i'll trade rolloff for speed & clarity every time. i really can't understand 15" port lovers. yes, the bass is HUGE and loud, but it's also sluggish and distorted.

    i actually developed my taste in bass listening to a friend's 4 1/2" infinity reference minis, complete with 3/4" styrofoam tweeters in the mid 80s. i'd visited FOUR different stereo shops before then, but until that point, never heard truly pinpoint imaging and bass with so much speed & detail even though it was seriously rolled off.... so THAT'S what a bass kick sounds like when you remove almost ALL of the bloat! OHHHH! i like 4 1/2" sealed bass much better than 10"+ plus ported ANY DAY! freedom from distortion beats loud bloat every time in my world... it also drives port lovers crazy, no matter how many well established facts you TRY to hit them over their hard stupid distortion loving heads with.

    i was banned for essentially telling a troll POSSE to go eff itself and the mentally challenged moderators chose to join them in their cause and single me out for defending myself, but thanks for reminding me that my time here hasn't been troll free. don't you have anything better to do with your time? are you going to chase me from thread to thread to keep starting crap because you too are a psychopath, much like your avatar, without a life?

    The One Psychological Characteristic That Online Trolls Tend to Share:
    http://www.alternet.org/media/one-psychological-characteristic-online-trolls-tend-share
    i was banned for standing by the well established over DECADES FACT (stated above) that ported speakers are nothing but hideous resonant distortion artifacts that idiot trolls couldn't deal with because it hurt their poor little feelers to admit that they like time delayed, out of phase, no woofer control, sluggish, frequencies that don't even exist in a recording because it's a big & loud distortion bass drum obscuring excuse for DISTORTED music whereas, i freely admit the ONLY limitations of sealed speakers, namely less efficiency & lowest octave extension (a much shorter list that DOESN'T include ANY form of distortion BTW) because i live in the real world where every choice has tradeoffs, and, unlike them, i have no problems admitting the limitations in my eliminate all distortion preferences.

    where STUPID people TRY to claim that ports are less distorted than infinite baffle, i don't reply in stupid kind and erroneously claim that infinite baffle designs have bigger deeper bass. that would be a lie, or at the very least, an indicator of out of touch ignorance, which the butt buddy moderator at DIY audio (that's right... eff you to death DIY audio and your busted troll butt kissing rat bastid moderators!) was keen to preserve and purge any truth bearing messengers who hurt his butt buddy's feelings.

    now, you were spraying, uninvited to MY thread TROLL BOY?

    oh... never mind... i found the mute button. now you can talk to yourself and never waste another millisecond of my time with your insecure self loathing psycho crap. please do mute me too.

    now... if only someone could invent a mute button for the real world that doesn't involve lawyers and courthouses...
     
    Last edited: Oct 15, 2016
  16. JimB

    JimB Super Moderator Most Helpful Member

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    Come on guys, let keep it clean and play nicely.

    There is no need for name calling.

    JimB
     
  17. tcmtech

    tcmtech Well-Known Member Most Helpful Member

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    And this is why YOU got kicked out of AAC and I didn't even get reprimanded over it. :rolleyes:

    The sad part is you are clearly still butt hurt over it too. :facepalm:

    Do you want to post the link to the other sites thread where you had the melt down so that anyone here can follow up on what this discussion about bicycle sound systems started as and how it actually came to fall apart or should I? o_O

    Either way. I smell another baning and thread lockdown on the way. :eek:
     
  18. tcmtech

    tcmtech Well-Known Member Most Helpful Member

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    BTW. Who are you quoting in your posts? o_O

    I see no one has actually asked any of those questions or made any of those points and you have not provided any links to suggest they are from real conversations elsewhere either yet you're all wound up about them anyway. :facepalm:

    Right now it appears that you are just having a pubic conversation onto yourself being you can't get a single knowledgeable person to agree with you on any forums.
    If so at least show the decency to set up a second proxy account here and run two or more different screen identifies so you don't look like a halfwit talking/arguing with to no one but his own reflection in the mirror. :rolleyes::oops:
     
  19. spec

    spec Well-Known Member Most Helpful Member

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    Afraid that was me TCM:banghead:

    I deleted all my posts because I decided to bow out of this thread.

    spec
     
  20. audioguru

    audioguru Well-Known Member Most Helpful Member

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    ONLINE
    I don't understand:
    1) A very high power sound system on a bicycle??
    2) People dancing to the bicycle music on the street??
    Isn't this the year 2016 and not 1977 when people danced in a discotheque?? The sound system in the disco was not moved around on a bicycle. Maybe today people dance in a night club that also does not move around its sound system.
     
  21. budget minded

    budget minded Member

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    no spec, it WASN'T YOU! another member that talked trash in my first attempt to solve all of my tech issues followed me here and started up again. the only thing you ever "did wrong" was talk over my head with techspeak i just don't understand. if anything, i was the problem there as i just got frustrated because my mind and the way i model things totally doesn't work like yours which is comfortable with concepts that are abstract to me and i really don't like abstractions.

    well, as high power as i can reasonably build and afford anyways. like i said, i'm not looking to "SPL drag race" (as in car audio competitions), just build the nicest sounding system i can and have it louder than a boombox

    people DO dance in the streets. women in particular LOVE IT as long as you're playing good music. when you have a bike system, people get really excited and want to join the party. as you're talking about discos... i bring it to them, but that's not the main reason for my building this system. i DESPISE the soulless wannabe gangsta crap they play in clubs, particularly on the west coast. i won't go to clubs because the music sucks. having my own system, i can play tunes that are mostly instrumental (i've never really liked rap from the beginning), funkier than the soulless techno junk other DJs play, and in general, music that has a bouncy, upbeat, playful vibe.

    you won't hear tunes like these in ANY club i've been to in 4 states these days:








    -or-



    and you won't hear them on any bike or car systems either.

    back to the system, i've decided that i'm going to start with a 1.9 cubic foot sealed 15" sub. i can get one for just $22 at MCM and the box for $42 right up the street. i checked subs out at pawn shops, and anything in the $50 range was pure junk... a 10" with broken terminals, another 10 with NO TERMINALS, a busted bandpass where the ports went the full height of the sub basically turning it into a 2x sealed sub, a 15" kicker that had sloppy white silicone repairs to the surround in a part plywood slot loaded junk box, and even the 12" kicker, i think, i listened to had terrible "ffft ffft ffft" cone flap distortion, possibly from a leaking bolt hole as it was mounted at an angle in a recycled box.

    the 15" poly i'm probably getting has a rubber surround (all the pawn shop subs had annoying foam surrounds too) and is 92dB efficient. i did the calculations, and it will have close to the ideal .7Q in the box i'm using. this is it's projected response...

    [​IMG]
    i'll be losing some of the speed i'd get out of the 12s i want to use, but using even 1 would be much more expensive as the high efficiency goldwoods i want to use are $70 each where 1 15" can move close to the same amount of air as a pair. i also kind of like the looks of the inverted dustcap and 6mm of travel isn't shabby. it, and its 8 ohm twin both got good reviews.
    [​IMG]
    General Specifications:
    • Nominal Diameter: 15 inch
    • Rated Impedance: 4Ohms
    • Operating Bandwidth: 50 ~ 3KHz (-3dB)
    • Power Handling Capacity: 200W RMS
    • Sensitivity (1W/M): 92dB (±3dB)
    • Voice Coil Diameter: 2 inch


    Thiele-Small Parameters:
    • Resonance Frequency Fs: 32.5Hz
    • DC Resistance Re: 3.4O
    • Mechanical Q Factor Qms: 3.203
    • Electrical Q Factor Qes: 0.5342
    • Total Q Factor Qts: 0.4578
    • Equivalent Cas air load Vas: 322.23 L
    • Surface Area of Cone Sd: 0.0840 m2
    • Efficiency Bandwidth Product EBP 60.8
    • Voice Coil Over Hang X-max 6 mm


    Physical Information:
    • Cutout: 13.82"
    • Mounting Depth: 5.63"
    • Basket: Pressed steel chassis
    • Magnet Type: 40.0 oz.
    • Cone Material: Polypropelyne
    • Surround: Rubber
    • Dust Cap: Polypropelyne
    • Damper: Cloth

    a $22 15" is pretty good boom for the buck to get started with, and will be lighter than 4 x 12s. who knows, i might actually keep it if it sounds nice enough with some bass boost. i also plan to line the cabinet with a contoured foam (poor man's acoustic foam) mattress pad. if it's too sluggish sounding or just can't hit low notes with any authority, i'll give the next person a deal on it at no more than $50 after i put probably twice that into it. locals here, like pawn shops, overprice beat up junk.
     
    Last edited: Oct 16, 2016

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