Subwoofer amp?

[webmailjojo]

Since the frequency response of that amp only extends to 80 Hz, it is useless for powering any sub.

Understand that, but in reality it does give frequencies from 45hz.

But apart from this, i want to understand whether a lower powered amp similar to mine (assuming freq range from 40hz) can destroy my sub in any way??

 

[TLS Guy]

Understand that, but in reality it does give frequencies from 45hz.

But apart from this, i want to understand whether a lower powered amp similar to mine (assuming freq range from 40hz) can destroy my sub in any way??

I have no idea. I don't know the circuit of that amp. For all I know it has no DC offset protection and if it fails it may send your sub driver literally up in smoke. A sun amp needs a response to 20 Hz by the way. If it an old cheap amp that is probably exactly what will happen.

 

[highfigh]

Understand that, but in reality it does give frequencies from 45hz.

But apart from this, i want to understand whether a lower powered amp similar to mine (assuming freq range from 40hz) can destroy my sub in any way??

It may do 45Hz but at nowhere near the level of -0dB to -3dB, which does make it useless for deep bass. Also, 45Hz isn't particularly deep bass- useful but with a small driver, it won't have much impact.

If an amp is driven past its useful range, either of frequency or input level, the wheels fall off pretty fast. So, to answer your last question, yes- it's definitely possible to destroy your woofer with a low powered amp. Much better to look for a deal on something that's usable for this application.

 

[webmailjojo]

It may do 45Hz but at nowhere near the level of -0dB to -3dB, which does make it useless for deep bass. Also, 45Hz isn't particularly deep bass- useful but with a small driver, it won't have much impact.

If an amp is driven past its useful range, either of frequency or input level, the wheels fall off pretty fast. So, to answer your last question, yes- it's definitely possible to destroy your woofer with a low powered amp. Much better to look for a deal on something that's usable for this application.

Thanks to both of you guyz. I am so happy that i have fallen into the right place for my specific problems. This site it so awesome.

Have a crazy question though. I'm trying to bridge the stereo output (120W+120w) of my HiFi to get more power for my sub which requires 200W @ 8Ohms. My HiFi is a Sony and rated 120X2 stereo RMS and i believe its got good freq. range too.

1. First of all, do you think its a sensible and safe solution for this poor man who is trying to utilize his current gears to power up a 200w bose MB4 @ 8ohms sub?
   
2. Secondly, could you advice me on how do i bridge such a connection if it makes sense in the first place?

 

[highfigh]

Thanks to both of you guyz. I am so happy that i have fallen into the right place for my specific problems. This site it so awesome.

Have a crazy question though. I'm trying to bridge the stereo output (120W+120w) of my HiFi to get more power for my sub which requires 200W @ 8Ohms. My HiFi is a Sony and rated 120X2 stereo RMS and i believe its got good freq. range too.

1. First of all, do you think its a sensible and safe solution for this poor man who is trying to utilize his current gears to power up a 200w bose MB4 @ 8ohms sub?
   
2. Secondly, could you advice me on how do i bridge such a connection if it makes sense in the first place?

The sub doesn't require 200W, that's its power handling rating and it's probably not accurate, if other manufacturers' rating are any indication. Also, unless the Sony is made for rugged use, it won't like being bridged and run hard. I can almost guarantee that the power supply was never designed to handle that kind of use. Also, you would have to find a way to invert the input to one channel (correctly).

If you want to bridge an amp, use one that was designed for it. It works much better and you won't have any surprises.

 

[TLS Guy]

Thanks to both of you guyz. I am so happy that i have fallen into the right place for my specific problems. This site it so awesome.

Have a crazy question though. I'm trying to bridge the stereo output (120W+120w) of my HiFi to get more power for my sub which requires 200W @ 8Ohms. My HiFi is a Sony and rated 120X2 stereo RMS and i believe its got good freq. range too.

1. First of all, do you think its a sensible and safe solution for this poor man who is trying to utilize his current gears to power up a 200w bose MB4 @ 8ohms sub?
   
2. Secondly, could you advice me on how do i bridge such a connection if it makes sense in the first place?

You have to have an amp that is able to be bridged if you don't know how to make a circuit to split the +ve and -ve polarities of the wave. Even then you easily blow amps doing this.

I have looked at your Bose sub. Unfortunately for a poor man you have made a big mistake in that you own a piece of equipment by Bose.

You have fallen foul of a common problem with Bose gear. It can only be powered by their equipment. Your sub, which really is only a bass unit, that is down by 3 db at 40 Hz, needs equalization to do that. You have to drive that sub with either a Bose 1600 or 1800 amp. And you have to buy the correct equalization card for that bass unit and insert it into the amplifier.

Trying to power it with anything else will be a frustration and waste of time. You have no chance that Bose will tell you what the Eq is, or the Eq circuit.

To top it off, like most Bose units, your unit looks like a total time waster.

My best advice is to sell that Bose unit for whatever you can get out of it. It is for certain not worth the trouble of you trying to power it. Dump it fast. Next time you see a sub built from 5 1/4" drivers, assume it is a con, and you won't be wrong.

 

[webmailjojo]

You have to have an amp that is able to be bridged if you don't know how to make a circuit to split the +ve and -ve polarities of the wave. Even then you easily blow amps doing this.

I have looked at your Bose sub. Unfortunately for a poor man you have made a big mistake in that you own a piece of equipment by Bose.

You have fallen foul of a common problem with Bose gear. It can only be powered by their equipment. Your sub, which really is only a bass unit, that is down by 3 db at 40 Hz, needs equalization to do that. You have to drive that sub with either a Bose 1600 or 1800 amp. And you have to buy the correct equalization card for that bass unit and insert it into the amplifier.

Trying to power it with anything else will be a frustration and waste of time. You have no chance that Bose will tell you what the Eq is, or the Eq circuit.

To top it off, like most Bose units, your unit looks like a total time waster.

My best advice is to sell that Bose unit for whatever you can get out of it. It is for certain not worth the trouble of you trying to power it. Dump it fast. Next time you see a sub built from 5 1/4" drivers, assume it is a con, and you won't be wrong.

wow..Bump

i just got this new, less than a month. Actually, i am already using a Yamaha amp for powering my two 802's, but i need to have an extra amp for the sub. Yup, i truly fell into the bose trap, well frankly speaking, pulled away from the jbl prx by those bose marketeers for reasons of portability, weight, sound, dispersion, brand blah blah I would never ever consider buying a bose amp for that horrendous cost. I even didn't know about the eq thingy. i definitely need to check into that. Thanks for the constructive criticisms.

Laters mate.

 

[TLS Guy]

wow..Bump

i just got this new, less than a month. Actually, i am already using a Yamaha amp for powering my two 802's, but i need to have an extra amp for the sub. Yup, i truly fell into the bose trap, well frankly speaking, pulled away from the jbl prx by those bose marketeers for reasons of portability, weight, sound, dispersion, brand blah blah I would never ever consider buying a bose amp for that horrendous cost. I even didn't know about the eq thingy. i definitely need to check into that. Thanks for the constructive criticisms.

Laters mate.

Then take it back for lack of full disclosure. First it does not meet the definition of a sub and they did not disclose that it needs proprietary Eq.

A sub, by the way, must reproduce at least most of the last octave. That sub rolls off at the start of the last octave.

 

[gregz]

...and if you can't return it, I think it's important to keep things in perspective:

Bose is the brand we all love to hate.

It's not that Bose flat-out sucks or is worse than the bargain brands you can find on the cheap. It's closer to the mid range. It's just that Bose markets aggressively with a lot of hype, and sells their products at inflated prices because they can. And they don't give out specs because they like to play the shell game on what you're getting. But in the end, the products they make aren't bad, and their subs can do justice, but they're not high end. Of course, a true high end sub would be over a thousand dollars just for entry - which is why we make our own.

My neighbor bought a cheap-azz subwoofer at a discount store, and I can hear that p.o.s. anytime he's watching a movie becuase it has a HUGE hump at around 50Hz and not much below that. The result is that every explosion, every gunshot, every soundtrack baseline, every jet - sounds EXACTLY the same: an amplified fart!

So if your Bose sub can get down just above the last octave, you're not doing too bad at all. As someone else in the forums pointed out recently, the lowest note on a bass guitar is 42Hz, so you have the span of most music people listen to. As for the specialized eq, you can pick up a used single channel 1/3 octave eq on the cheap and tweak in the response. It may not be a perfect match for Bose's proprietary correction, but I find it very hard to believe that you can't come very close.

I'd start by cutting off all frequencies below 30Hz for starters until you can carefully test the lower range ability of the sub with a bass test CD at low volume.