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k58.cross

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k58.cross last won the day on February 20

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  1. Crescendo Symphony S1 Monoblock! 1500Wrms for $300, footprint the size of a Brazilian amp, and you can wire lower than 1 ohm as long as your sub is near the rating of the amp. I ran a DB-SA2712 at 0.5ohm nominal on this amp with absolutely no problems. Crescendo ALLLL day man. I am trying to sell mine because I upgraded to the Bassclef 4k, but I can't post it for sale yet because my post count is too low. On a different (completely unrelated) note, I noticed my PM box here is completely functional.
  2. There will be specific frequency band in the bass spectrum where power draw is highest. You can download an app on your phone that's a signal or tone generator and just go through the frequencies until you see highest power draw. That's actually your worst case. The loudest bass notes are typically at port resonance and power draw will be low there (which is a good thing). Your voltage dropping to 12.5 just means you used your alternator's current up and now you're drawing from the batteries as well. Adding another battery won't bring you back up to 14+ just FYI. Three batteries for 4kW...I don't know if that's excessive, but extra juice is always good. Each battery has a limit to how much instant current it can let out, so more batteries will let you handle those bursts better. It's up to you how much money you wanna spend and what you have room for.
  3. These cells say 3C continuous, so does that mean 3*60=180A continuous discharge rating? How about short duration discharges? Could it safely discharge 300A over say 1 second?
  4. Seems like nowdays people only really use caps for burps in SPL comps. Difference between cap and battery is that a cap discharges and charges much faster, so good for those hard and fast BUUURRPPP uses. But on a daily driver, I think you're way better off just supplementing with batt power.
  5. Ah so you want to have your port coming out of the top of the box? That's possible with aero ports, and maybe you don't need to bend, check this example pic: My system is in dissaray right now because I'm renovating it a bit and making things look better. I got my box done though and this is how I have it set up: It's a compromise though. I know I need more port area for the power I'm trying to run. It's a small car though so just doing what I can for now.
  6. OP, use what you got and focus on making a good enclosure. Instead of trying to throw a ton of power at it right away, figure out how to get the most of your system first, and then move up in power, otherwise it's wasted potential. Stop flex wherever you can in the vehicle, it's lost SPL. That's why the loudest SPL vehicles are built like tanks. Put in a dedicated volt meter and watch how much your battery voltage drops during normal use. If you regularly dip under 12, you need an extra battery.
  7. Impedance changes greatly by frequency, and so does power draw. Low power draw doesn't always mean low SPL, because the system draws less power when it's operating efficiently and/or resonating. When you clamped, did you do it at the frequency where power draw is highest? If not, go back to low-medium power and sweep frequency while watching power draw. The highest power draw will probably be at a frequency that doesn't sound very loud, like 65 Hz or something. Clamp there.
  8. I looked up pics of the interior of your year Scion TC and it looks similar to what I've been dealing with - 2011 Ford Fiesta sedan (it's a sub-compact lol). In the trunk of that thing I fit a 28x24x15 box with 8x17 aeroport (halfway in box, halfway out) and 2 12's. The box is around 5 cubes net, and I can put the back seat up fully, although it's more output with the seat down. I have the port facing into the cabin. Also a XP2000 (medium size AGM) on either side of the box, and the amp is in the wheel well under the box. It's tough to get everything in, but is possible
  9. Was pretty fun to see the making of a $20 slinky It would be interesting now if you tested a 400Wrms (or close to it) sub from a reputable maker like Sundown or IA and show how much more abuse it can take.
  10. I just bought some Crescendo Mezzo 6.5's for $250. They haven't shipped yet though. Comes with nice tweeters and crossovers. Hoping the SQ is good and will let you know after they're installed. They sounded like they had good midbass in the videos I watched. For what it's worth too, I heard Deaf Bonce mids (except the neos) have really good midbass.
  11. I second this. For around the same total price, is lithium better than AGM, and why? Because we are talking about hundreds, sometimes thousands of dollars more for lithium. Why why why? I get the weight advantage. I understand lithium has a charging rate disadvatage. Now the other important aspects of battery power are discharge rate, capacity, and lifespan. So how do those compare to AGM of a similar overall cost. Let's say for example you bought $500 worth of AGM batts and $500 worth of lithium batts (assume trustworthy brands).
  12. For what it's worth, I looked into this more and yeah, shelf brace is stronger than hemisphere brace of same width. The nerd explanation is that it has to do with the area-moment of inertia. Cutting a cylinder in half cuts the MOI in half, so I would imagine it would reduce the AMOI by more orders of magnitude. A 1"x1" half round brace of same length as 1"x1" rectangular brace will have less than half the stiffness (maybe more like a quarter...not sure the math on that one). Now when you extend the length of the dimension working against the force (sound waves), the 1"x1" rectangle increased to 1"x4" gained 76 times more stiffness. So yeah. What's worse is you can't increase the radius of the half round without increasing it's width too. So it's just not feasible like the shelf brace. A sound wave causes both outward and inward deflections though right? I wonder how that works for the inward case.
  13. I used the ts params you posted up there and got the -3 dB point at 48 Hz. SPL wasn't very high in a sealed box of 2.3 cubes (for 2 subs) maxing at 116 dB (not considering cabin gain). But there were some ts params not included, not sure if they would make a difference. Honestly for $270 each, that's not much power handling, unless they are under-rated. I'm not familiar with this brand. Also, it says up to 150 DAYS wait time....Damn I could not wait that long myself. I'd suggest Deaf Bonce or Sundown, I've used both and they're great. Deaf Bonce will be a bit cheaper, Sundown more rugged. Edit: Just noticed SA V3 12's are on sale for $195 right now. That's a "750 wrms" sub, but I'm sure you could easily slap it with 1k.
  14. Same as most of the SMD products, they aren't insanely expensive but are a bit pricier than they should be. They're marketed towards people that want the most-used features in an easy to understand interface and don't mind dropping the extra cash. You can pick up a Rigol scope and a BNC current clamp for 400 and have the added benefit of seeing the signal on the screen, among other things. Just need to have some electronics knowledge to calculate things.
  15. I'm glad he did, I didn't know about this one! On a side note, it's pretty clear the forum used to be more active than it is today. I see some of current posters in these old threads, but alot of people seemed to have moved on. Kinda sucks but understandable. Word to Ky, obviously a vet here.
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