general sub advice

So I was feeling motivated this weekend and decided to figure out why the sub in my car doesn't work anymore. I originally suspected the pre-amp outs on the head unit had gone south.

After some testing I decided it must be the sub so I finally took it out of the box and realized the cone wouldn't move... I figured a 600w RMS to 1600W peak sub would be fine on my "little" 800W peak MTX Thunder801D amp. Well, I know next to nothing about RMS vs Peak let alone when I have to figure it out for 2 voice coils. So I chatted up someone through Crutchfield's live chat. Apparently the 800W peak is more or less constant power (RMS i guess?) from my amp when it's getting 14.4v. I guess normally this would be peaks or spikes, but since my car puts out 14.4v almost constantly my amp is pushing 800w ALL the time.

I suppose that's why I've blow every sub ever hooked to this amp! I never though I'd need to get a sub with an RMS value between 800w and 1000w. He recommended an Alpine sub, but I'd rather not be spending $449.99 on it!

So does anyone have any suggestions for an inexpensive dual 4ohm sub in the 800-1000w RMS range? I have the box from my last 10" so something in the same size would be nice, but I guess I could build a bigger box for a 12". Certainly don't want to go any bigger since we use the trunk.

And, again, since this will be the 4th (5th?) sub I've bought for this damn amp, I'd really rather not spend too much! Under $100 would be great, but only if someone knows of one in that range that won't get smoked in a few months!

The Crutchfield guy kinda educated me saying you need to push at least 70% of the RMS rating on the sub. (Someone correct me if he was wrong.) Based on that, and the amp pushing 800w I should be looking at a sub with an RMS rating of at least 680w per voice coil for dual 4ohm.

This is giving me a headache! So any good models with that power handling, 10" or 12", decent price, and maybe places that sell them too? I've been searching, but of course most sites don't let you filter by power rating and I'm getting frustrated looking!

Edit:

This is in a 1998 Corolla. I just want general info/advice on subs, places to buy, etc. So it can stay here or put back in off topic. I don't care.

 

Have you looked into Elemental Designs? They really have some amazing subs that are built really well, and are competetively priced too.

My 8" hits like most 10" subs.

 

No, I haven't, but I will now!

I just have this massive headache from searching, comparing specs, and trying to figure out what will work.... Ya know? Thinking back I know for a fact now I've blown 3 subs before this last one, and frankly I'm tired of going through this! But I paid $400+ for the amp a few years ago, it works fine, and I kinda hate to not use it. Seems pointless to pull it out and shelve it in the garage. No point in trying to put it in the truck as there's no good place for a sub, and I'd need a new head unit anyway.

I wanted to contact MTX to see what THEY recommend for THEIR amp, but all their websites are down as far as I can tell. Can't find much info on them from other sites, and their products seem to be dropped from some retailers so I'm wondering if they went under.... (Not to mention it seems their domain name is available now - mtxaudio.com) Not that I could sweet talk them into sending me one for free for my trouble, but worth a shot right?

Instead, I sent an email to Power Acoustic since my last sub was one of theirs. Will if the get back to me and what they say.

 

I won't comment on what the Crutchfield guy said but I will let you know that those older MTX amps put out more than their rated power (I've seen birthsheets well over 1000 watts of REAL power). Unfortunately I cannot think of any subs in your price range that will handle that much power In any case, amps don't blow speakers...the person controlling the volume knob does!

 

Yeah, I've read my MTX manual a few times and see that it puts out more than it's rated for. My problem is that I'm a bit confused about how much power the amp puts out all the time. I thought the 800w "peak" power was just a max output that would spike during high volume with lots of bass. I rarely have it very loud anyway. My apline head unit's volume goes up to 20 or 30 I think, and I usually have it around 4 or 5 if that gives you an idea.

I've been told if you multiply the voltage by the value of the fuses you can get the amp's max theoretical power. As in, my car puts out 14.4v, amp has 75A worth of fuses. So that would be a max output of 1080W. I assumed (incorrectly must be) that a sub rated for 600w RMS, 1600w peak would be more than enough. And it lasted for 1-1.5 years so maybe something else caused it to seize up. I don't know. I'm a computer guy, not an electrical engineer or sound technician!

And for what it's worth, one of the subs I blew was rated for 1000w, and it blew as soon as I turned the music on. I had the volume low, was standing behind the trunk, and had the remote so I could make sure it worked. Well, pushed power, then play, and a puff of smoke appeared.

 

Those amps came with birthsheets (power certification sheets) that tell you exactly how much each individual amp actually puts out based on actual testing of that amp. Also, from what I remember MTX does not use the term "peak" in their power ratings (that's a marketing gimmick and don't pay attention to peak ratings when comparing) rather they use "maximum" power which is typically the rating at 14.4 volts (engine running). At 14.4 volts the 801d is "rated" 400x1 into 4 ohms and 800x1 into 1 or 2 ohms however the birthsheet for each amp will be different and a bit higher. Then to make things even more confusing an amp can theoretically produce twice it's rated power when it goes into clipping which is a reason the gains need to be set properly! In any case an amp does NOT do full power all of the time since power output is directly related to where you have the volume set and that relationship depends on how the input sensitivity is set in relation to the the pre-out voltage of the headunit.

Basically what I am saying is you can use a 1000 watt amp on a 100 watt sub if you want to as long as the amp is set up properly and you don't push the volume knob past the limits of the subwoofer

As for your sub blowing when you turned it on, I'm guessing there was a short somewhere, a defective amp or a defective sub as the ONLY other thing that kills subwoofers is too much power.

Is that confusing enough for you?!

 

Yeah, I have the birthsheet......somewhere. I know it's more than 800W, but don't remember the actual number.

Thanks for clarifying "peak power". That makes sense. So I should expect (or rather perhaps plan) for it to be putting out 800W (or more) all the time since the car puts out 14.4v. So I'll make sure I buy something with an RMS range 800-1000.

Any brands/models/resellers you'd recommend?

 

Marv, remember he said he normally only uses 4-5 on his deck when the volume "goes up to" 20 or 30. My guess is he has the gains cranked and is clipping the crap out of it when he does get on it. Now, 800wrms on a single sub that will fit in a Tacoma is hard to come by,

 

The amp will technically put out 800 watts when the engine is running only if you turn the volume knob to that level. What year model truck do you have and are you trying to find a sub that fits in the enclosure you already have? If so how much airspace does it have?

That would be a reason the subs blow for sure!

 

It's for a 1998 Toyota Corolla... Which is why I originally put it in the off-topic section... Should probably add that into the OP.

I have a box already for the last 10" that I could use, or get another one at some point. I just don't want to be spending $200-$400 or more on something that may do the same thing.

I may have the gain turned up a bit. I'll have to check. I know I don't need the speakers inside the car that loud.

 

You could also run a dual 8-ohm coil speaker. That would limit the output of the amp somewhat, depending on the amps output current capabilities.

 

True. My previous subs were single 4's with the last one being my first dual 4. I liked how it sounded, and it was the longest lasting one. Well, my 10" Xtant 10" may have lasted close to the same... But I added a second battery one winter to keep the lights from dimming, and I think the sub went within a couple weeks of that. So not sure if the amp was able to get full power after that and over power the sub, or if it had something to do with random -25F nights. That was a single 4. Just decided to try the Power Acoustic Fubar-10 since it was fairly cheap at Best Buy, and I thought it had the power rating I needed.

 

http://electrovoice.com/products/300.html

Paul Klipsch used Electrovoice in his speakers, back when Klipsch speakers were worth listening to. Handle a buttload of power cleanly, but they're super efficient so you don't have to drive any of the electronics into clipping to get some good thumping.

The link I sent is single VC though, haven't dug enough to see if they make dual VCs.

 

My first recomendation would be a Image Dynamics IDMax 10", if money is tight then I would go with a Fi Q 10" www.ficaraudio.com

 

Thanks. It's more like I have more important things to spend $100 or more on at this point since my wife isn't working. That, and I'm kinda tired of dropping more money each year on subs!

 

Oh, and feel free to comment on what he said! I'm here for info so I'd appreciate any knowledge you care to share. I'm well aware of your abilities at fitting sub enclosures from reading TN.

 

Fosgate P3 from Ebay - with the gains on your amp turned down!!

 

Piercedtiger id suggestion some diamond subs. My friend has two 10's in his dodge and it sounds great.

 

Let me know the airspace of the enclosure if you know it (or the measurements of it) and I'll see if I can recommend something that will work well with that enclosure, get the most potential from the amp and within your budget (seems a few missed the part that you have a $100.00 budget ).

There is no need to limit the amp with a higher impedance sub since you can do that with the volume knob. In any case a more common dual 2 ohm or single 4 ohm sub would do the same thing as a dual 8 ohm (unless you were referring to wiring it in series for a 16 ohm load )

If you had a single 4 ohm sub the amp's max would have been 400 watts. If you had a single sub with dual 4 ohm coils the amp would put out a max of 800 wired in parallel or 200 wired in series. As far as the second battery damaging your sub I doubt it but -25 degree weather could in fact cause a problem. Also, subs like Power Acoustic are famous for "fudging" their specs and I suspect that was why you blew that one.

That driver has a response from 100-2000hz so it wouldn't be very useful as a "sub" woofer unfortunately.

If you can find either of those for his budget of $100.00 I'll take a pallet!

At that price point it is going to be difficult finding something to get the full potential from your amp but there are some good subs out there that would work well for you in that budget.

Ah crap, no more anonymity for me around here!

Unfortunately I do not have time now to explain all of this as well as how different voice coil configuration affect things however I will say that you should disregard ANYTHING that says "peak" and concentrate on constant power ratings. The other thing I'll mention again is NO amp does it's full power all of the time or it would be playing at full volume constantly! Somewhere above I explained how the amp output is relative to the position of the volume knob in relation to other things-turn it up amp produces more power and sub gets louder, turn it down and amp produces less power and sub is not as loud. For the sake of simplicity in explaining let's say an 800 watt amp would produce 200 watts at 1/4 volume, 400 watts at half volume, 600 watts at 3/4 volume and 800 watts at full volume (it doesn't work exactly like that but hopefully you get the idea).

 

The volume control..I was answering on the implied fact he doesn't turn the volume control down.

Don't understand "In any case a more common dual 2 ohm or single 4 ohm sub would do the same thing as a dual 8 ohm". He appears to be running two channels of output to the sub, so assuming one driver running dual VCs in series is out. So a 2 Ohm is half a 4 Ohm, a 4 Ohm is half a 8 Ohm, and I understand those are "nominal" resitances that vary with frequency. Amps tend to clip a lot less at seen higher impedance loads, but of course a 16 Ohm load isn't really ideal either. If he bridged the amp, and ran a dual 4 in series, that would be a 8 Ohm load, or just a single 8 Ohm driver, either would limit the output current of the amp.

Efficiency of the driver also comes into play, one with a SPL of 93db at 1 foot will require a lot less power to drive to intolerable volume levels than one with a 88db SPL. Lots more headroom in the amp before it starts squaring off the peaks.

Was going on the 10 inch sub, since space in tacos isn't all that much.

How about this one: http://electrovoice.com/products/307.html

There's several sizes available, of course the bottom end changes with driver size, the cabinet size and type, construction, mounting, resonant frequency and damping effect of the envorment it's firing into.

You're going to be hard pressed to find ANY 10 inch sub that'll honestly go below 100hz..and if you do, they're going to be rated down there at -3 or -6db (or worse), or their distortion level is so high you wouldn't want to listen to them.