What additional elements do I need beyond amp and batt?
Can I charge this batt from 120v house power?
Does this amp have the XO elements I need based on Frank's XO design for my case?
-Do you think you will use this plugged in to the wall more or by itself running off of the battery?
-There is a special charger for the Odyssey battery but it isn't expensive and can charge any other battery you may own, 12VDC that is.
-You will also need a 12VDC transformer but they aren't expensive either. Battery charger and transformer for under $50.
-What was Frank's XO design? I'll have to go back and find it. The amp has the majority of the XO you'll need. A low pass to the Woofer and a high pass to the mid/fullrange and tweeter. An additional passive XO will be needed for the tweeters and maybe an L-pad.
I wonder if you can wire the transformer and 12V battery in parallel. Plug in the transformer without disconnecting the battery. This would make things easier. If the battery is sitting at 13.2V and the transformer is making less than that then the battery would come down to it's level right, higher voltage.
-Do you think you will use this plugged in to the wall more or by itself running off of the battery?
I'd like to plan to run it off the battery as much as possible.
-What was Frank's XO design? I'll have to go back and find it. The amp has the majority of the XO you'll need. A low pass to the Woofer and a high pass to the mid/fullrange and tweeter. An additional passive XO will be needed for the tweeters and maybe an L-pad.
This was what Frank wrote about the XO design...based on Zuma's Podzuma...
Originally Posted by fbov
- tweeter highpass (half of Darren's XO)
- mid lowpass to match tweeter (other half of Darren's XO)
- mid roll-off in a sealed box (occurs naturally)
- big woofer lowpassed (in car amp) to fill below mid roll-off
- woofer tuned for bass peak, to add perception of bass outdoors.
Originally Posted by fbov
XO
The only thing you want to watch here is the DCR of the coil on the woofer. 0.4mH is fairly small, so it won't cost much to go heavier gauge. It reduces the only parasitic load on the PA130's, so they'll play a little louder. I'll assume audio-grade caps and low-inductance resistors as these are SOP (and you can go wild here, too.).
I got an email there was a new post.
-I like the battery option, maybe get a couple/few and always have one charged.
-That amp doesn't have crossovers or enough power for the woofer.
-I like my charger better. http://www.ebay.com/itm/12-VOLT-MOTO...item2c66737b45
I wonder why I can't see the other thread posted by johnviera.
I spoke with some folks at work about wiring the battery and transformer in parallel and just using which ever one you want to at the time. If the transformer only makes 12VDC output, not 13.2 or 14.4VDC like many battery chargers and alternators do, then wired together will work. It would even charge the battery part way when using the transformer.
If it makes more than 12VDC then a simple switch or relay will have to be used. I just ordered a 12VDC/20amp transformer so I can tell you what it makes. It was under $30 shipped.
The battery charger I linked comes with a pigtale to attach to the battery for easy hook up to charge.
I spoke with some folks at work about wiring the battery and transformer in parallel and just using which ever one you want to at the time. If the transformer only makes 12VDC output, not 13.2 or 14.4VDC like many battery chargers and alternators do, then wired together will work. It would even charge the battery part way when using the transformer.
If it makes more than 12VDC then a simple switch or relay will have to be used. I just ordered a 12VDC/20amp transformer so I can tell you what it makes. It was under $30 shipped.
The battery charger I linked comes with a pigtale to attach to the battery for easy hook up to charge.
Wow that is great news. Thanks for digging into it. Please let me know what you find when the transformer arrives.
For rechargable batteries, it's hard to beat sealed lead acid (gel cell) for cost/weight vs. performance. $2.50/Ah online. I like the 7Ah batteries as they'll last a couple days in this application. The only critical advice is to buy an appropriate charger for that battery technology, and use it religiously!
I'd have suggested a sealed suitcase from the start if I thought this application needed it. I don't think you do, and the main reasons are that you're porting it, and not trying to dig too low. That greatly reduces the acoustic stresses, making an openable case an option, and allowing an "all-up, all-in" solution that contains all the elements, but still looks like a suitcase when it's playing.
All we do is point to options; the OP makes decisions. Openable is the reversible option; you can always seal it later if you want. And I advise against internal access through the driver cut-outs. It only takes one slip to put the screwdriver through the cone, and you'll wear out woodscrews so add T-nuts if sealing it up.
The initial amp specified (ALPINE MRP-F300) has everything you need, per the manual.
- L/R go on channels 1/2
- sub on channel 3/4, bridged
- HP/LP filters selectable and adjustable for each pair (HP on 1/2, LP on 3/4)
- gain adjustable for each pair
Not sure what else you might want... HP filters like this make the PA130 sub-enclosures purely optional. 50W/ch is a good fit to the drivers, too, especially the PA310. Remember, we sensitivity-matched the PA310 to a PA130-based MTM, so bridging provides excess power to the big driver, if you want a lot of thump. Not enough to cover the full +12dB bass boost, mind you, unless you're gentle with the volume...
Power
I like a switch. Either AC charges the battery, or AC runs the amp, not both. But that's me; Darren's design is switchless.
If looking to run an audio amp on AC, you'll need:
- a transformer
- a rectifier
- a bank of caps to smooth the 120Hz ripple.
Far, far easier to buy one, but expensive to buy one that's got the current capacity to drive the amp to rated power. The one thing to remember is that you don't operate at rated specs. This amp wants a 50A fuse, but a 5A power supply will serve you well.
To try and clear up some details, I've sketched the circuit diagram, below, linking Darren's XO's and DC power path to the intended driver configuration. With a clean DC power supply and battery-matched charger, the rest is just details.
So...
- l like the amp
- the gel cell battery should suffice; deep cycle car battery is great but overkill and heavy to boot.
- get the correct maintenance charger from the folks who sell the battery or you'll buy new batteries sooner than necessary.
- get a separate high-current power supply.
This one a bit weak, but at least it's intended for audio applications. http://www.parts-express.com/pe/show...number=320-312
This shows you a lot of options: http://www.ebay.com/sch/i.html?_nkw=12v+power+supply
But be sure to check the specs: http://www.ebay.com/itm/New-12V-DC-3...item1e6f0524a5
This one looks great - 29A for only $31... until you look at the ripple. 1% ripple in the power supply is not what you want!
Power
I like a switch. Either AC charges the battery, or AC runs the amp, not both. But that's me; Darren's design is switchless.
What is the reason for your preference? All else being the same, I assume it would be nice to be able to run the amp and charge the batt at the same time.
Far, far easier to buy one, but expensive to buy one that's got the current capacity to drive the amp to rated power. The one thing to remember is that you don't operate at rated specs. This amp wants a 50A fuse, but a 5A power supply will serve you well.
Sorry, I don't follow you. It's far easier to buy *one what*?
To try and clear up some details, I've sketched the circuit diagram, below, linking Darren's XO's and DC power path to the intended driver configuration. With a clean DC power supply and battery-matched charger, the rest is just details.
So great, thank you! I'm going to brush-up on how to read schematics.
...What is the reason for your preference? All else being the same, I assume it would be nice to be able to run the amp and charge the batt at the same time.
Yes, your car will charge the battery and run all the accessories at the same time, but only becasue all the components are designed to do so. The trick with DIY is that you're the design engineer, so you have to consider compatibility between battery and it's charging/charge maintenance needs, and the power needs of the amp. You can ruin a battery by overcharging, just as much as by leaving it uncharged. No speaker sounds good on a dead battery!
That said, as long as the battery spends most of its time with no load, or connected to a proper charger, you can use it many ways. One good option is as a current buffer to an undersize (i.e. cheap) power suppy. 12v gel cells are ~12.4v when charged. A 12V power supply wouldn't charge it much, and when load exceeded power supply capacity, voltage would drop and you'd start to draw on the battery. You just wouldn't want to leave it connected this way all the time, thus I'd still want a switch.
Did I ever link you to my portable system? I don't even use a switch, I plug and unplug connectors, and have both a charger and a power supply. Pics at the bottom show it in portable mode, as well as the intended application. http://techtalk.parts-express.com/sh...light=drive-In
Sorry, I don't follow you. It's far easier to buy *one what*?
DC power supply, rather than make one from a transformer, rectifier and caps.
So great, thank you! I'm going to brush-up on how to read schematics.
One trick for turning a schematic into a circuit is to recognize the "nodes," places where several components connect. For example, in the Podzuma XO, woofer circuit, the + side of the driver connects to both the cap and coil, as well as the other driver's + side. It's a 4 component node. The - side is also 4 component node, but with the 2 driver - sides, the cap and the - input. Identify the nodes, solder those connections, and you've created the circuit on the schematic. Tie down the componets so nothing rattles and you have your crossover.
I just got the transformer I ordered in the mail today. I haven't had a chance to hook it up but....it has a gain control knob to adjust the 12VDC voltage + or -. I'm gonna email the seller and see what range it will adjust the voltage to as I don't see me getting my set up together sooner than they could email me.
This is the one I bought. http://www.ebay.com/itm/110840547570...84.m1497.l2649
As far as the battery I linked to, the Odyssey, it may be overkill and have features you won't need. In retrospect, Amp Hours would be the most important aspect of a battery for the Jimi-Case. Also to have Deep Cycle properties so it can be charged and drained and charged back up with out dieing.
These both speak directly to the great power trade-off - capacity vs. mass.
Odyssey 16 Ah (?) battery
Product Dimensions: 7 x 3.1 x 6.6 inches ; 15.4 pounds
12V 20A power supply (there's a lot more than a transfomer in that box, and I'd really like a ripple spec - let's see what you hear!)
Dimensions: 19*8.7*4 cm, 632g
12V 7Ah gel cell
•Length 5.95 in.
•Width 2.56 in.
•Height 3.71 in.
•12 Volt 7.2 Amp Hour (Ah) at 20HR Rate
7 lb. shipping wt.
Looks like the battery question is driven by cost as weight is scaling with capacity - the more it weighs, the longer it'll play. Dual 7Ah will give the same capacity, weigh the same, but cost 1/3 as much. The power supply trade-off is just a matter of matching capacity to actual need, and a battery buffer allows for a much lower capacity (smaller, lighter) power supply, but you have diminished capacity if your battery's dead. Everything's a trade-off.
Oh man. I am so sorry. I admit I got bogged down a bit in the technical details and then got sidetracked and busy and put the project aside for a while. But I am committed to seeing this project through and I apologize for being negligent to everybody that has helped me so far and I hope you'll continue to help. I feel like once I purchase the components (drivers have been chosen, seems like we were starting to narrow down amps and batts), the actual build will move steadily, with expected construction and technical challenges.
Ok, I just went back through the thread to get myself caught up again and this is where we're at (cobbled together from invaluable advice from Frank, 901Fixer and others):
Amp
- L/R go on channels 1/2
- sub on channel 3/4, bridged
- HP/LP filters selectable and adjustable for each pair (HP on 1/2, LP on 3/4)
- gain adjustable for each pair
Dual Batts
14Ah total
*Switch between charger and house power
---------------------------
CONSTRUCTION
- Fiberglass interior of case
- 1/2 inch panel of birch on the front baffle
- The case itself will act as the enclosure for the woofer
- No need to build boxes for the mids as the amp provides HP (is this correct??)
- Possibly a box for the amp and batts??
- 1-2" ribs perpendicular to, and up-and-down the back panel for rigidity
- A piece of holey-bracing between the large woofer magnet and the back panel
- Foam (pillow stuffing or carpet underlay) on all walls that don't have speakers
- Weatherstripping around the seals
---------------------------
Definitly put those mids in their own enclosures. You want to separate the backwaves from each driver. When you are putting this kind of time and effort, not to mention $$$, youd not want to settle.
Re: First speaker project- Suitcase enclosure
Originally Posted by 901Fixer
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