[SilentJ20]

Well, I was all set to click the order button for the Oaudio 500W BASH plate amp, but now I am reading very mixed reviews about using it with a ported sub.


I was choosing it because of the selectable subsonic/highpass filter and the PEQ. From arguments I've read, it's the filter--or the boost that is associated with it--that will not do well with my ported design (Dayton RSS390HO-4, 150L, Tuned to 16-18Hz).


Is the Oaudio BASH a bad choice? If I do decide to use it, is there anything specific I should be careful of with the boost/subsonic filter settings? Would the Dayton HPSA500 500W amp be a better choice? Thanks for any help.

 

[penngray]

who said it was a bad choice?


What does filter/boost have to do with a ported design anyways?


Reviews are a complete waste of time IMO. Im pretty sure that amp has been used successfully on hundreds of ported subs.

 

[mobius]

I like the fact that you can bypass the filter.

 

[SilentJ20]

Here's the thread where people discussed the good/bad:

Oaudio BASH discussion Boost discussion starts at about post #8.


Being fairly new to sub design--and amp selection--I wanted to hopefully get a straight answer. The way I was understanding it--which could be completely wrong--, the boost before the filter frequency would put extra power into the sub just before the tuning frequency, which would cause excursion to go a bit far.

Quote:
Originally Posted by penngray /forum/post/18209074


Im pretty sure that amp has been used successfully on hundreds of ported subs.

That's what I thought, but with all the "boost is bad for ported", talk I was reading, it pays to make sure and hopefully get a good descriptive answer in the process.

 

[penngray]



Quote:
Originally Posted by SilentJ20 /forum/post/18209116


Here's the thread where people discussed the good/bad:

Oaudio BASH discussion Boost discussion starts at about post #8.


Being fairly new to sub design--and amp selection--I wanted to hopefully get a straight answer. The way I was understanding it--which could be completely wrong--, the boost before the filter frequency would put extra power into the sub just before the tuning frequency, which would cause excursion to go a bit far.




That's what I thought, but with all the "boost is bad for ported", talk I was reading, it pays to make sure and hopefully get a good descriptive answer in the process.

Well BOOST below the tuning frequency is bad, yes.


Are you saying the amp has a setting to boost below the tuning frequency? Im sure its adjustable? I would suggest not boosting below the tuning frequency.

 

[jpmst3]

If not adjustable, probably easily modded.


I thought that model had a PEQ built in, if so, could you simply cut at that freq?

(perhaps the EQ does not go down that low)

 

[wackii]

You can use REW to measure it and put that to rest. I did this to my old receiver. I wasn't sure if the crossover on my old receiver was accurate or not... so I measured it using REW... I'm pretty sure you can do the same with this amp...


Here is a graph of my old receiver crossovers... This put my doubt to rest...

Al,

 

[jpmst3]



Quote:
Originally Posted by wackii /forum/post/18209300


You can use REW to measure it and put that to rest. I did this to my old receiver. I wasn't sure if the crossover on my old receiver was accurate or not... so I measured it using REW... I'm pretty sure you can do the same with this amp...


Here is a graph of my old receiver crossovers... This put my doubt to rest...

Great idea and point.

 

[wackii]



Quote:
Originally Posted by jpmst3 /forum/post/18209166


If not adjustable, probably easily modded.


I thought that model had a PEQ built in, if so, could you simply cut at that freq?

(perhaps the EQ does not go down that low)

I dont think it is adjustable, but you can mod it if you have the schematic. I would use that single PEQ to where it really needs.


Al,

 

[jpmst3]



Quote:
Originally Posted by wackii /forum/post/18209349


I would use that single PEQ to where it really needs.

I would too, but if it means using the amp vs. not then...


Also, one band is usally not enough anyway, so there may be a BFD or some other EQ in the mix anyway.

 

[SilentJ20]

Well, it doesn't have boost below the tuning point. Maybe I was interpreting something wrong. In a ported design, there is a displacement "hump" right above the tuning frequency. I was worried that this hump would get blown even higher with the boost above the filter frequency. Then I thought about it. The amp is rated at 500W. If I design it so that the hump is acceptable at 500W, things should be fine since even at max power, the boost should not exceed 500W that the amp will deliver, right? The amp would clip first (still not a good idea, I'm just trying to clear things in my head). Does that sound right?

 

[synthesis08]

The boost is minimum at higher subsonic filter setting so it doesn't matter. I use this amp for my ported subwoofer and I don't have any issue.

 

[SilentJ20]

Is there any way to add the characteristics of this amp into a unibox simulation? For checking behavior of different filter/boost settings on my design?

 

[penngray]



Quote:
Originally Posted by SilentJ20 /forum/post/18209493


Is there any way to add the characteristics of this amp into a unibox simulation? For checking behavior of different filter/boost settings on my design?

filter/boost is all just EQing and WinISD does have EQing in it. You will see what it does to your excursion too.

 

[penngray]



Quote:
Originally Posted by SilentJ20 /forum/post/18209462


Well, it doesn't have boost below the tuning point. Maybe I was interpreting something wrong. In a ported design, there is a displacement "hump" right above the tuning frequency. I was worried that this hump would get blown even higher with the boost above the filter frequency. Then I thought about it. The amp is rated at 500W. If I design it so that the hump is acceptable at 500W, things should be fine since even at max power, the boost should not exceed 500W that the amp will deliver, right? The amp would clip first (still not a good idea, I'm just trying to clear things in my head). Does that sound right?

All you need to figure out is your max excursion. What Watts and what power will push the driver past its limits.


Definitely use WinISD to simulate this.

 

[synthesis08]

You can make an educated guess from the boost/subsonic filter curve from the amp manual.

 

[SilentJ20]



Quote:
Originally Posted by penngray /forum/post/18209514


All you need to figure out is your max excursion. What Watts and what power will push the driver past its limits.


Definitely use WinISD to simulate this.

I'll have to fiddle with Winisd a bit later. I'm more comfortable with unibox, so I'll have to re-learn some of winisd first.

Quote:
Originally Posted by synthesis08 /forum/post/18209521


You can make an educated guess from the boost/subsonic filter curve from the amp manual.

I guess I could try plotting the points by hand and see what happens...

 

[wackii]

If you have selectable subsonic filters then I don't think you'll have a problem. Adjust your subsonic filters accordingly even if there's a boost, you probably be safe

Again, you can measure that subsonic filters too using REW

I dont think you'll have any issues. If you have buyer's remorse, can you cancel it before shipping? Also, how loud do you listen to music/movies? Are you a basshead type of person? If you dont listen too loud and not a basshead, you should probably be safe

Al,

 

[SilentJ20]



Quote:
Originally Posted by wackii /forum/post/18209561


If you have selectable subsonic filters then I don't think you'll have a problem. Adjust your subsonic filters accordingly even if there's a boost, you probably be saved

Again, you can measure that subsonic filters too using REW

I dont think you have any issues. If you have buyer's remorse, can you cancel it before shipping? Also, how loud do you listen to music/movies? Are you a basshead type of person? If you dont listen too loud and not a basshead, you should probably be safe

Al,

Well, this will be the first time I will have ever experienced significant bass during movies. I'm stepping up from a 100W sealed 12 inch. So the output from this will be orders of magnitude higher. I just want to make sure I can get the most out of it I can for when I move into a new house with a (hopefully) larger theater room.

 

[penngray]



Quote:
Originally Posted by SilentJ20 /forum/post/18209535


I'll have to fiddle with Winisd a bit later. I'm more comfortable with unibox, so I'll have to re-learn some of winisd first.




I guess I could try plotting the points by hand and see what happens...

Maybe Unibox has EQing features? I have never used it so I do not know.