external sub amp question

Andon

Andon

Audioholic
Hi all, I have two ported 12" subs with bad plate amps. Each is rated at 300 watts RMS they ate same make and model. I will lake to ask for advice what external amp should I use to power them? I know I can replace plate amps, but who knows how long the china amps will last!! Any help will be appreciated.
 
j_garcia

j_garcia

Audioholic Jedi
Which subs matters and you didn't mention what they are. Ideally, you want the same amps because they're usually tailored to that design, so you'd want to start with the manufacturer first. If you can't get them, an external could work but might not work exactly the same as the original. You also then need to bypass the original amp.
 
Andon

Andon

Audioholic
The subs are polks PSW505. I am planing to remove the amp plates and put a metal plate with cut out for binding posts.
 
Andon

Andon

Audioholic
I know, they are not the best subs out there but that is what I have and I will lake to put them back in use.
 
lovinthehd

lovinthehd

Audioholic Jedi
I use Crown XLS series amps for my diy subs. They don't have helpful dsp, though, particularly if you need to set a protective high pass filter (as is fairly common with ported subs to prevent over excursion below tuning). You can add a miniDSP unit to the Crown, tho that adds expense and I'd minimize it to get Polk subs running. A used Behringer dsp-enabled amp (they used to be called the iNuke DSP series, think they're NX with a "D" designation now) may be more useful and cost effective but may come with a bit of fan noise. I am not a fan of plate amps, unless they're top quality like SpeakerPower maybe. Overall I think it's time to think about new subs, tho.
 
Andon

Andon

Audioholic
I have Yamaha PX3 on my mind for $400 at crutchfield to power them for the moment, until l can afford a pair of Dayton Audio 15" Ultramax and then use the same amp with the Daytons.
 
lovinthehd

lovinthehd

Audioholic Jedi
I have Yamaha PX3 on my mind for $400 at crutchfield to power them for the moment, until l can afford a pair of Dayton Audio 15" Ultramax and then use the same amp with the Daytons.
Looking at the HPF choices for sub frequencies only 20 & 40 hz it appears....
 
TLS Guy

TLS Guy

Seriously, I have no life.
I know, they are not the best subs out there but that is what I have and I will lake to put them back in use.
I see you problem is that this is going to cost more then the subs are worth probably. If you do not push them then you probably will get away with just a dual channel external power amp like a Crown.

The problem is that they are inexpensive "pigs in a poke." So if you push them with no high pass filter you probably will destroy the drivers. So ideally you should use a high pass filter at around 20 to 25 Hz range, 12 db per octave to protect the driver. Mini DSP would fit the bill for this.

The issue really comes down to how much you want to put into those subs. If you use them gently, or don't care if you take the drivers down then go ahead. After all you will have the amp to power a decent DIY sub or other passive sub. The latter though are far and few between.
 
AcuDefTechGuy

AcuDefTechGuy

Audioholic Jedi
Yamaha PX3, Crown and QSC will work.

 
William Lemmerhirt

William Lemmerhirt

Audioholic Overlord
Definitely be careful with them. Out of the box they fall off a cliff at 25hz. Not sure what they’ll tolerate below that.

On the surface, for 300 bucks, I’d look at just buying these and put the polks in a closet until you can squirrel away for something to power them.
Just don’t know if it makes sense to spend 400 bucks on an amp to power a 300 dollar subwoofer.
 
lovinthehd

lovinthehd

Audioholic Jedi
Yamaha PX3, Crown and QSC will work.

The Crown XLS amps lowest frequency for HPF is 30hz. Didn't see in my glance at the PX3 manual the increments available that are mentioned in the AH link....
 
William Lemmerhirt

William Lemmerhirt

Audioholic Overlord
The Crown XLS amps lowest frequency for HPF is 30hz. Didn't see in my glance at the PX3 manual the increments available that are mentioned in the AH link....
I wonder if an Fmod would work?
 
AcuDefTechGuy

AcuDefTechGuy

Audioholic Jedi
The Crown XLS amps lowest frequency for HPF is 30hz. Didn't see in my glance at the PX3 manual the increments available that are mentioned in the AH link....
I owned the Yamaha PX3 for about a week when I wrote those posts on AH. I was playing around with the increment changes for the HPF. That's how I knew the increments were 0.5 to 0.6 Hz apart.

For Sub amp, I would go with the PX3 for sure.
 
lovinthehd

lovinthehd

Audioholic Jedi
I owned the Yamaha PX3 for about a week when I wrote those posts on AH. I was playing around with the increment changes for the HPF. That's how I knew the increments were 0.5 to 0.6 Hz apart.

For Sub amp, I would go with the PX3 for sure.
Maybe I didn't dig deep enough into the manual but seems they coulda mentioned that where I was looking!
 
AcuDefTechGuy

AcuDefTechGuy

Audioholic Jedi
Maybe I didn't dig deep enough into the manual but seems they coulda mentioned that where I was looking!
Well, you know what they say about "manuals" in general. :D

It doesn't seem to matter which company it's from, most manuals just suck. :D
 
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