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Discussion Starter #1
Looking to upgrade the sub amp in my truck. Sub is 12" Image dynamics IDQV3 Dual 4 ohm ran in parallel.

Sealed underseat box. ~1f3 airspace.



current amp is a JL500/1. Not quite enough power for my liking. Size is limited to 14" in either direction.


Amps I've given thought to:

HD1200.1
Alpine PDX M12
Massive N4
Rockford fosgate T1500bd

Any other suggestions? The JL @ $900 is the absolute max I'd be willing to spend.
 

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You're only going to gain 1.7dB between your 500w and the IDQ's rated 750w, you know.

Also, stop looking at JL amps. They are WAY overpriced.

If I were to buy an amp right now, it'd be a Nakamichi PA-1500.
 

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Discussion Starter #4
You're only going to gain 1.7dB between your 500w and the IDQ's rated 750w, you know.
Well, I'm not looking for more SPL really, it just seems like when I want just a little more from my sub it gets mushy. I thought getting a bigger amp with more headroom would eliminate this?
Also, stop looking at JL amps. They are WAY overpriced.

If I were to buy an amp right now, it'd be a Nakamichi PA-1500.
Thank you for the suggestion! I will look into the Nakamichi's. Price is certainly attractive.
 

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Well, I'm not looking for more SPL really, it just seems like when I want just a little more from my sub it gets mushy. I thought getting a bigger amp with more headroom would eliminate this?
1.7dB is rather minor. Honestly, I think you'd be better off adding another sub.
 

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Discussion Starter #6

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Well, yeah, porting would also give you more output. It is a valid option as well.

Go listen to your stereo at some volume. Then turn up the volume by 2dB (assuming your H/U does volume in 1dB steps). The amount that it will change by doing that is sliiiightly more than moving from 500 to 750 watts.

The minimum amount generally considered to be a reasonably significant difference in volume is 3dB, and it takes twice the power to get that. Even then, that's not a huge difference... that's about what it takes to be able to walk out of the room, walk back a few moments later and realize that someone turned the volume up.
 

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Discussion Starter #8
Well, yeah, porting would also give you more output. It is a valid option as well.

Go listen to your stereo at some volume. Then turn up the volume by 2dB (assuming your H/U does volume in 1dB steps). The amount that it will change by doing that is sliiiightly more than moving from 500 to 750 watts.

The minimum amount generally considered to be a reasonably significant difference in volume is 3dB, and it takes twice the power to get that. Even then, that's not a huge difference... that's about what it takes to be able to walk out of the room, walk back a few moments later and realize that someone turned the volume up.
Ok...I see what you're getting at with the numbers. I'm confused though. If I had a 350 W amp driving my sub, it wouldn't sound "slightly less loud", it would sound quite a bit softer...wouldn't it? I've never owned anything higher than this JL for RMS wattage.

Does a harder hitting sub = more SPL? Because I want it to hit a little harder and cleaner at higher volumes. It really made sense to me that a smaller amp with the gains turned up (~75%) will strain at say volume 33/40 where you could put a larger amp with the gains @ 30% or so, would hardly be working at volume level 33/40.

It's quite interesting the stark contrast in opinions I get on this site.
 

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Nope. Going down to 350w would barely be noticeable.

As for how to get SPL, that's simple. Excursion of the subwoofer equals SPL. Period. If you go ported, then it will be a combination of the output of the subwoofer plus the fact that the airflow in the port itself will combine at certain frequencies (around the tuning frequency of the port) to raise the efficiency of the system.

Port your box, add another subwoofer, or replace your subwoofer with something capable of higher power and excursion like an LMS-R http://www.parts-express.com/pe/showdetl.cfm?Partnumber=293-658, and put a bigger amp on it.

Edit to note: I did NOT check if that subwoofer will mount in your box or anything, so don't just go and order it without checking it out. It's just one example of a driver that will get you more output without being a crappy sounding SPL-only driver.
 

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I would absolutly recommend the rf t1000-1bdcp or t1500. love those amps.. 1500 does 1900 At 1 and 2 ohm and 1100 at 4
 

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What if I had 2?

Just get the HD1200.1, it attracted you for a reason. Buy right the first time instead of wondering later on and still buying the same thing you wanted in the beginning and thus wasting even more money. JL makes GREAT stuff. Don't let anyone tell you (especially mr. dragonrage who apparently only buys DIY or obscure offbrand stuff, let alone thinks alpine type R subs suck) otherwise. I have actually owned JL HD amps and heard them. They sound GREAT. The footprint of the HD amps is hard to beat with 1200.1 off PATENTED constant power technology. I beg for mr. dragonrage to argue with me if he wants.
 

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Ps you could EASILY get the HD1200.1 authorized for much less than that $900 you posted
 

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^ HD1200.1

1200 watts at anything between 1.5-4 ohms??? How is this a question? Especially if you're thinking about getting another sub, this amp would be perfect. JL is well known for their great customer service and quality products. They make great amps and great subs. Rage at that.

If I didn't have Audison amps, I would be going full JL not questions asked.
 

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I was considering the HD 750 or HD1200 mostly... couldn't decide if it was worth the extra money for the HD1200 powering a Morel Ultimo 12. I found a Alpine PDX 1000.1 for $250 so I went that route.

Possibly do what I did.... look for something used & see what you think. If you don't like it you can probably sell it for about what you have in it... minimal loss. I haven't been a alpine amp fan since I sold them back when the V12 stuff first came out.... but I couldn't refuse the cheap price, small chassis etc.....
 

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Just get the HD1200.1, it attracted you for a reason. Buy right the first time instead of wondering later on and still buying the same thing you wanted in the beginning and thus wasting even more money. JL makes GREAT stuff. Don't let anyone tell you (especially mr. dragonrage who apparently only buys DIY or obscure offbrand stuff, let alone thinks alpine type R subs suck) otherwise. I have actually owned JL HD amps and heard them. They sound GREAT. The footprint of the HD amps is hard to beat with 1200.1 off PATENTED constant power technology. I beg for mr. dragonrage to argue with me if he wants.
Excuse me? Nakamichi is an obscure brand? I think you should go study a bit more before you want to come slinging insults for no reason. Nakamichi is a very respected old school brand. They've since been bought out but they are still a Japanese company and their stuff is still good, and it's priced pretty reasonably.

As for JL, when did I insult JL amps at all? They are great amps. My previous system used a 500/5 and it was a great amp. But there is absolutely no reason to pay $900 or even half that. There are plenty of great amps for a third the price and you will not even know the difference. The JL is not going to sound any different - at all. You JL fans always love to jump on me for claiming stuff like "JL is good, but in this situation..." or "JL is good but you can do the same for a much better price" as if I were claiming "JL Audio is the worst company ever." Do JL Audio fans have trouble understanding written English? Is that the issue here?

Oh, and OOH, PATENTED TECHNOLOGY! WOW! Any marketing department putting the word "patented" in their product literature like consumers really give a hoot ought to be fired.

You guys are giving him awful advice. Buy a $900 amp (or $700 or whatever you will claim he can get it for) for a couple of decibels with the possibility of blowing the sub up if he's not careful? Are you guys only here to get people to waste money just because you like a product?

Get out of here.
 

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Discussion Starter #19
Excuse me? Nakamichi is an obscure brand? I think you should go study a bit more before you want to come slinging insults for no reason. When did I insult JL amps at all? They are great amps. My previous system used a 500/5 and it was a great amp. But there is absolutely no reason to pay $900 or even half that. There are plenty of great amps for a third the price and you will not even know the difference. The JL is not going to sound any different - at all.

Oh, and OOH, PATENTED TECHNOLOGY! WOW!

You guys are giving him awful advice. Buy a $900 amp (or $700 or whatever you will claim he can get it for) for a couple of decibels with the possibility of blowing the sub up if he's not careful? Are you guys only here to get people to waste money just because you like a product?

Get out of here.
I don't waste my money. I bought my 500/1 used for $200 because I wanted to experiment before I committed big money to amps.

I respect your opinion, but you're the only one so far that thinks that I wouldn't benefit from a larger amp. I would really appreciate it if you could steer me towards some other discussions regarding this.

This is how I'm thinking: I'm pushing my current amp as hard as I can to get to ~80% of my subs recommended (max) RMS rating....pushing amps hard is not good for the amps, subs or sq. Would my SQ not benefit for me to get an amp running at ~50% to deliver full (max) rms wattage? At 50% or less gain there should be 0 issues of clipping or distortion, things I may get while pushing my smaller amp to the limits?

Please take my comments with all due respect, you sound like a guy who knows whats up.
 

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The thing is, on an online forum such as this, you'll get a lot of responses from people advising you to buy this or that just because they like the product. It's not their money, after all. Sure, sure, you will gain output with the HD1200.1 or the PA-1500 or any of quite a few good amps that would work for you (most of which are much cheaper than the JL and will work just as well), but the objective fact is that you will gain output in decibels by the formula gain = 10*log10(Pout/Pin) e.g. 10log10(750/50) or 1.7dB. And it is also an objective fact that 1.7dB is not much to the human ear.

Here's an example of how little 1.7dB is. Say you were with a friend in your car and you had to run into a convenience store for a couple of minutes. Your friend turns your stereo up 2dB while you're gone. Most likely you wouldn't even notice he touched the volume when you got back without looking at the display. In fact, some people wouldn't even notice if you turned the volume by that amount with them still IN the car if they didn't actually see you do it.

Any good amp will not have too high a THD at rated power. A cheaper amp like the Massive Nano series has rated THD of 1.0% at rated power which is a bit much, but JL amps are better than that. Also, amplifier THD is much harder to hear in a subwoofer, anyway.

You can buy an amp if you really want to. It will give you a LITTLE bit more output and will prepare you for a subwoofer upgrade in the future. But, again, the HD1200 is not what I recommend, and again, that is SOLELY due to the ridiculous price. The only kind of deal that would make that amp worth buying is a deal from a guy who picked it up when it fell off the back of a truck. And that's not a deal that you want to take advantage of.

I will even note that the HD1200 IS better than the PA-1500 that I linked if running at 2/4 ohms, though the PA-1500 is still above the IDQ's rating at 2 ohms. But I can link you plenty of other amps that are much cheaper than the JL (but a bit more expensive than the Nak) that will do the same. And if we're talking brands that jooonnn likes - meaning brands that he can buy at Wal-Mart or Best Buy - I would take Rockford amps over JL amps (but JL subs over Rockford subs).
 
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