12V.. how much is possible? |
Post Reply | Page 123 4> |
Author | |||
nilspixel
Registered User Joined: 02 March 2021 Status: Offline Points: 77 |
Post Options
Thanks(0)
Posted: 02 March 2021 at 12:15pm |
||
hi all! i came across this topic from 2019 and was wondering, what has happened to the project. i'd love to build something very similar... https://forum.speakerplans.com/12-v-simple-system-for-reggae_topic103222_page1.html for now i don't really have any ideas on how to start. the only thing i know is that i want to build a mini stack on 12V and put it to use outdoors. it will be carried on a bicycle trailer with a maximum capacity of 1608 x 610 mm and 136kg. so plenty of space to fill... i don't want to become an electrical engineer and keep things as simple as possible. Car Preamps might work for that? A Tham15 and a Mid Top would be great... but i don't know too much about what is possible and what not... I need a kickstart from someone who has some experience :) thanks and all the best
|
|||
studio45
Old Croc Joined: 16 October 2007 Location: United Kingdom Status: Offline Points: 3864 |
Post Options
Thanks(0)
|
||
Much is possible! MUCH ;)
A Tham15 and a midtop is a pretty good place to start. But, you might want to look at something a little smaller if you're planning to tow it around a lot, and/or use car batteries (lead acid). A Tham15, 10" midtop, 75Ah battery and amps should *just about* be under 136kg. However, I know from experience that towing anything over 75kg is very difficult on hills, and pretty hairy in terms of stopping/ going round corners - good brakes and wide tyres are a MUST. So maybe a Tham12 and an 8" midtop might be more manageable - that was the first iteration of the Commotion rig and it worked very well. The current standard recommendation is to buy Pioneer GM-D series amps. They are powerful, efficient, light weight and very affordable. They have a built in crossover to separate the bass from the mid tops, and can run direct from a phone aux output or a Bluetooth adapter. The only minor downsides are - they can only run from 12v batteries not any higher voltage, and they have no fundamental highpass filter to cut off useless sub-20Hz frequencies that waste battery power. You might want some kind of mixer to go on the front end - again Pioneer have some nice pieces that run from a 5v power supply, which is easy to get from a 12v battery and car USB adapter. There are vastly lighter alternatives the lead-acid batteries of course - lithium being the main one. You have to think about voltages a bit carefully as lithium-ion cells are 3.7 volt nominal whereas lead-acid are 2.0 volt nominal. So if you have a Pioneer or other car amp that's expecting a max voltage input of 14.5v (with engine running) you can't really use Li-Ion cells to make a battery that can be drained fully while not going over-voltage for the amp at full charge - three in series is 11.1v, four in series is 14.8v so you can't hit that "12v" sweet spot. Lithium iron phosphate (LiFePO4) cells at 3.2v nominal are a better match - a set of 4 in series give a 12.8v battery that works well with car audio gear. Don't expect to save any physical space with lithium batteries, they normally end up being about the same size as lead-acid - but 1/3 the weight!
|
|||
Studio45 - Repairs & Building Commotion Soundsystem -Mobile PA
|
|||
nilspixel
Registered User Joined: 02 March 2021 Status: Offline Points: 77 |
Post Options
Thanks(0)
|
||
hey studio45, thanks for your opinion. i'm glad someone responded that quickly :)
i found this site with suiting plans for a THAM12. http://https://www.martinsson.cc/blog/index.php?m=03&y=12&entry=entry120315-210219 A Beyma 12LX60 driver is fine for my project? what do i have to watch out for when buying drivers for 12V usage? any recommendations for a 8" midtop? :) New Plan:
cheers EDIT: As I'm not planing to do any DJing outdoors a Mixer is not a necessity... AUX is entirely sufficient :)
Edited by nilspixel - 02 March 2021 at 6:38pm |
|||
slaz
Old Croc Joined: 27 November 2009 Location: London E2 Status: Offline Points: 2713 |
Post Options
Thanks(1)
|
||
As usual, I'd endorse pretty much everything studio45 said. Couple of things to add ... Actually this should probably be a "sticky" for this section. Pretty much all car amplifiers rate their output with a supply voltage of 14.4V or close to that. When using them on a off-grid situation (i.e. standalone battery power, no charge from a car alternator) - and assume a median discharge voltage of - say 12.5V - the real world power o/p will be about 3/4 of their rating .... e.g. a 100W amp becomes actually about 75W. Near the end of discharge cycle - say 11.5V - that goes down to about 64W. Not an enormous difference in SPL (1 or 2 db), but the amp _will_ clip earlier/easier. Also (esp with lead-acid) the voltage will be more prone to sag under heavy load - which can cause clipping/distortion .... needs to be borne in mind when you set your levels. If you want a baby mixer to just have single line in (e.g. laptop, tablet, phone etc.) and a decent mic input ..... take a look at the Behringer 302USB. It has good o/p level (can drive a proper amp if needed), has a good mic pre-amp with good overload margin (1/4" jack/XLR combo connector) and can be powered all day from a USB phone power bank thingy. Having its own power supply neatly side-steps any possible ground-loop hassles. Mine has performed like a champ with a MC and also when someone gets up and wants to have a little sing-along :-) |
|||
REMEMBER....POLITICIANS AND DIAPERS SHOULD BE CHANGED OFTEN AND FOR THE SAME REASON
|
|||
slaz
Old Croc Joined: 27 November 2009 Location: London E2 Status: Offline Points: 2713 |
Post Options
Thanks(1)
|
||
By repute, a EV SX80 (8" mid/bass + comp driver) will do a good job. A good deal lighter than most 8+1 cabs made from plywood (its a plastic moulded enclosure ... but a good one). Should play well down to 100Hz or so. |
|||
REMEMBER....POLITICIANS AND DIAPERS SHOULD BE CHANGED OFTEN AND FOR THE SAME REASON
|
|||
nilspixel
Registered User Joined: 02 March 2021 Status: Offline Points: 77 |
Post Options
Thanks(0)
|
||
you got me with this one! will get one! :)
thanks for your recommendation :) but to match the look i'd want to make it from plywood just like the THAM12...
Edited by nilspixel - 03 March 2021 at 3:52pm |
|||
APW
Young Croc Joined: 13 November 2012 Location: Kent, UK Status: Offline Points: 1174 |
Post Options
Thanks(1)
|
||
The little 8" two way Eighteen Sound cab works well with a Tham 12 Link to plans:
|
|||
nilspixel
Registered User Joined: 02 March 2021 Status: Offline Points: 77 |
Post Options
Thanks(0)
|
||
Alrigth, so things come together a little more. But still some stuff left i don't understand... Say i want a Pioneer GM-D8604, Class D 4x 120W @ 4 Ohm. It has 4 channels which can be used to power 4 speakers? https://ibb.co/QCw3WBr - When every channel has 120W.. do i have to look out for the drivers not to be above 120W? Am I restricted to 4 Ohm? thanks again :) |
|||
nilspixel
Registered User Joined: 02 March 2021 Status: Offline Points: 77 |
Post Options
Thanks(0)
|
||
Ok i just answered this by myself. The amp mentioned above is able to be bridged to use it as a 2 channel machine!! nice. got that now... the TwoWay speaker linked by APW has all the electronics inside and uses one input for both drivers...
|
|||
nilspixel
Registered User Joined: 02 March 2021 Status: Offline Points: 77 |
Post Options
Thanks(0)
|
||
As the data from the used drivers in the provided Two Way Cabinet seemed a bit too much i found this one: https://celestion.com/blog/build-this-compact-10-two-way-pa-speaker-design/ What do you mean? |
|||
nilspixel
Registered User Joined: 02 March 2021 Status: Offline Points: 77 |
Post Options
Thanks(0)
|
||
Okay guys, i just ordered the amplifier (Pioneer GM-D8704) to have a start on this project. Also some sheets of 15mm birch plywood is on its way to my workshop.
For now the project consists of the following:
Edited by nilspixel - 03 March 2021 at 10:40pm |
|||
APW
Young Croc Joined: 13 November 2012 Location: Kent, UK Status: Offline Points: 1174 |
Post Options
Thanks(0)
|
||
When you say the drivers are too much what exactly do you mean... Cost? If so you can use cheaper drivers, the Fane Sovereign 8-225 or Fane Sovereign Pro 8-225 both work in the 8" Eighteen Sound cab and the compression driver can be substituted by the Eighteen Sound XD125, the CDX1-1445 used in the Celestion cabinet or something like a Beyma CD10Fe… The Eighteen Sound horn used in that cabinet is fairly cheap!! Edited by APW - 04 March 2021 at 9:42am |
|||
Post Reply | Page 123 4> |
Tweet |
Forum Jump | Forum Permissions You cannot post new topics in this forum You cannot reply to topics in this forum You cannot delete your posts in this forum You cannot edit your posts in this forum You cannot create polls in this forum You cannot vote in polls in this forum |