Portable Subwoofer advice needed! |
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mashgwan
Young Croc Joined: 20 May 2004 Status: Offline Points: 613 |
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alphabetikal- what voltage were you running the sure amp at?
also does it make any differeance to the bass of your rel enclosure if you hold it slightly off the ground like the standard rel quake enclose ?
only reason i ask is that i am in the middle of aquiring 2 rel drivers and was going to use them of a sure amp that i already had on order
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KWB75
Registered User Joined: 10 November 2007 Status: Offline Points: 259 |
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To be honest its a waste of those drivers - the sure amp isn't great on bass regardless of voltage, it's got a nice tight controlled sound to it but its not for subs - much better suited to drive full range.
I run mine off 24v driving 2 monacor sp60/4, sounds nice. |
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mashgwan
Young Croc Joined: 20 May 2004 Status: Offline Points: 613 |
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im a bit limited to what i can use, this rig is going to be an outdoor system for a camper van so the amps has to be efficient as my batterys are also running a fridge freezer
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alphabetikal
Registered User Joined: 20 May 2010 Location: UK Status: Offline Points: 217 |
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yo
sorry for delay in post reply i was running Sure at 12V only. It was 'there' (much better with than without) but it wasnt really pumping how i wanted it to and the obviously at 12v you get limited power output. 24V might be OK tho! The Rel sub is clearly good quality (although i bought it off this forum for a cheap deal). Perhaps it might run nicer on 24v but to be honest I feel like it needs a active EQ or crossover in there to boost the low freqs nicely. the sure amp is a cheapy like others have said - it doesnt do bass too well. i have no idea how low frequency wise my sub goes. I literally got the thing, found out it needs a 11 litre box and put it in one. it is slightly raised off the floor, it has some little rubber feet you can't see. A Edited by alphabetikal - 12 November 2012 at 3:21pm |
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mr. doom
Registered User Joined: 08 September 2010 Status: Offline Points: 266 |
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Sure 2050's have much better bass impact with 24v. @ 4ohm. I run six 10" PA drivers off of one.
I think it about doubles the wattage, +3db/ 45 vs. 90watts... (although I hear that there is not much difference from 24-30v) The regular inefficient sub driver for home/car are designed to work in tiny boxes with a ton of power. They are not going to do much without juice. Here is a bit from Parts Express Q&A's ant the amp. As I'm guessing you know, the amount of power that this amp can put out is dependent on the power supply's voltage: the higher the voltage, the higher the power output. With your current setup of a 12V power supply and 8 ohm speakers, this amp is only capable of putting out about 9W/channel. This is a very small amount of power, especially in an outdoor environment, so it makes sense you're getting clipping: to get the volume output you need, you always have to be running near its maximum output of 9W, and when those transients hit (from piano chords, etc) you will get sudden, short clipping because the amp simply cannot output a voltage as high as what's demanded from it. If you double the power supply voltage to 24V, the power output capabilities will quadruple to about 36W. If you then use 4 ohm speakers instead of 8 ohm speakers, you'll be up to 72W. This is 8 times as much power as you currently have, which is almost a 10dB increase, which means it would be twice as loud before clipping. If you wanted to get up to the full rated output power of 100W, you'd have to use the maximum power supply voltage (32V), but it sounds like that would be unnecessary for you. By increasing the power output capabilities, the amp should be able to handle the high output voltages demanded during transients, and thus the clipping should be minimized a lot, and will probably be eliminated. Using more efficient speakers could also make a substantial difference. For example, if you find speakers that are 3dB more efficient than your current speakers then you could run the amp at 3dB less power while getting the same volume output. 3dB is half power, so that's a pretty big difference, electrically. Adding a large reserve capacitor in parallel with the power supply (and putting it RIGHT at the board's power input pins) might help a bit, but I kinda doubt it. If your battery is reasonably large (ie, about 2Ah or more) then it should have no problem delivering the current spikes that are required from this amp during transients. Rechargeable batteries in general are quite capable of delivering high amounts of current. Plus, there are already quite a few reserve capacitors built onto the board. But, adding a large reserve capacitor is very cheap to do, so you pretty much may as well do it anyways. Edited by mr. doom - 12 November 2012 at 5:29pm |
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slaz
Old Croc Joined: 27 November 2009 Location: London E2 Status: Offline Points: 2713 |
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O/p at 24V will be close to 4 x the o/p at 12V. If you have a decent-sized single 12V battery - here's one way to get 24V from it :- http://www.ebay.co.uk/itm/190557328369?ssPageName=STRK:MESINDXX:IT&_trksid=p3984.m1436.l2648 .... tried and tested by me. |
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REMEMBER....POLITICIANS AND DIAPERS SHOULD BE CHANGED OFTEN AND FOR THE SAME REASON
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mr. doom
Registered User Joined: 08 September 2010 Status: Offline Points: 266 |
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What would be the minimum battery you think those upvoltage things would work with?, got one in the junk bin. I have a cheap (6800? mah cctv batt)... Only lasts about two hours @12v turned up. My heavy 24v 7ah sla's do about four hours. |
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slaz
Old Croc Joined: 27 November 2009 Location: London E2 Status: Offline Points: 2713 |
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I'd say don't bother even trying a CCTV battery with the up-converter. The CCTV batteries work great for me - powering a 2020 amplifier - which has very light current draw. The o/p from a 2020 amp is about the same as a 2050 driven at 12V .... so thats a no-brainer. Pretty much any SLA can easily supply enough current to drive the Maplin thing - its just a matter of how long you want to run for. I was powering 2 channels of 2050 via car laptop adapter (24V) ... ( a lower rated 80W version actually) .... 2050 driven fairly hard - for about 5 hours from a 24Ah SLA - and the battery still had PLENTY left in it. I suspect the mean current draw in that situation (i.e. 2 channels of 2050) is about 1A - 1.5A in the 12V line - so even a 7Ah SLA should get you about 4 hours. If you're driving 4 channels of 2050 it'd be better with something like a 18Ah SLA..... I should say I haven't driven 4 channels off a Maplin thing .... but its rated a 5A - seems to be pretty efficient too - if heat dissipation is a decent indicator. |
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REMEMBER....POLITICIANS AND DIAPERS SHOULD BE CHANGED OFTEN AND FOR THE SAME REASON
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alphabetikal
Registered User Joined: 20 May 2010 Location: UK Status: Offline Points: 217 |
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thanks both for the tips on the 12v/24v issue. im going to give it a go... only 2.99 where can ya go wrong? (well im banned from ebay first off so thats a bad start)
the sub speaker i have is 4ohm so should be nice will report back findings cheers a
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t.geessounds
Young Croc Joined: 10 May 2010 Location: US... New york Status: Offline Points: 908 |
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< ="application/x-premieropinion" id="pluginBm" ="true">check these out i build 2 for 6.5 an 2 for 8" ant the really put out some nice bass :) |
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davey t
Young Croc Joined: 11 March 2004 Location: Bristol UK Status: Offline Points: 1428 |
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Good thread. We've built dozens of portable sub prototypes over the last year... sealed gives great sound but you need heavy eq and xmax to go low. Small Reflex designs work well with heavy stiff cones and long throw drivers but you really need work on the port design. Has anyone tried passive radiator ?
We've Finally settled on a tiny 1.5L mini beast. It'll still do 90db at 55Hz. Out soon ;) |
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Minirig portable soundsystem movement
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ashnono
Registered User Joined: 11 March 2004 Location: United Kingdom Status: Offline Points: 443 |
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do you have any of the drivers left for sale Markie?
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