A Sub Just Shouldn't Make Certain Noises

[fuzz092888]

They may have some insights, as they have the circuits. They don't even have a block diagram of how the thing is organized. So that makes it easier for them as we are somewhat in the dark.

One of the things that distresses me these days is that user manuals are much poorer than they used to be. This is a pity as the equipment is more complex. The general assumption is that the user us too dumb to understand a decent manual, including circuits and a parts list. They may well be right, but that is a dreadful take on prevailing engineering and scientific general knowledge. All decent gear used to come with a circuit and description of operation and it still should.

You may well have some work to do, but that should not surprise you. There is no off the shelf solution to a really excellent system. For that varying degrees of customization are required. There is always some to do. The more complex the system the more there is to do.

I have no problem learning more and investing some money in getting the subwoofer integrated as best as it can be. It will only help the other speakers and future subwoofers. Although knowing what I need is a different story. I know you mentioned: dual channel scope, signal generator and FET VOM for instruments. Would I then be using something a DEQ2496 to adjust everything or something different?

 

[TLS Guy]

I have no problem learning more and investing some money in getting the subwoofer integrated as best as it can be. It will only help the other speakers and future subwoofers. Although knowing what I need is a different story. I know you mentioned: dual channel scope, signal generator and FET VOM for instruments. Would I then be using something a DEQ2496 to adjust everything or something different?

That unit could certainly be used for your sub roll off equalization. For just one function, equalizing a 12db per octave roll off at a known corner frequency, I would build the equalizer. That would be especially true if it was just to insert between the Antimode and the amps. That Behringer unit is overkill, but it would do the job. Mini DSP would also do the job for you.

In your above situation, you would use the generator to generate the dialed in frequency and vary the voltage. The scope would show you the wave form. It is a lot easier to see early clipping than hear it, plus you can measure the peak voltage were it starts on the scope.

A FET VOM is a high impedance amplified meter, that will not lead an output, and give you accurate RMS measurements.

 

[fuzz092888]

That unit could certainly be used for your sub roll off equalization. For just one function, equalizing a 12db per octave roll off at a known corner frequency, I would build the equalizer. That would be especially true if it was just to insert between the Antimode and the amps. That Behringer unit is overkill, but it would do the job. Mini DSP would also do the job for you.

In your above situation, you would use the generator to generate the dialed in frequency and vary the voltage. The scope would show you the wave form. It is a lot easier to see early clipping than hear it, plus you can measure the peak voltage were it starts on the scope.

A FET VOM is a high impedance amplified meter, that will not lead an output, and give you accurate RMS measurements.

Well I already have the Behringer, so what if I swapped out the antimode for the Behringer and used that for sub EQ? Do you think that would work better and what would I have to do to make that work?

 

[TLS Guy]

Well I already have the Behringer, so what if I swapped out the antimode for the Behringer and used that for sub EQ? Do you think that would work better and what would I have to do to make that work?[/QUOTE

You would place it between the LFE and your Crown. You would dial in the inverse of the parameters I posted above. It is the inverse of your subs roll off. I would set the subsonic high pass filter to 20 Hz second order.

If you want room correction as well, then it would be LFE to Antimode, to Behringer to Crown. You would set up the Behringer before inserting the Antimode device.

The Antimode is not designed to equalize the roll off a sealed sub, it is to equalize room modes, which is very different, and I believe the source of your problem. The Antimode, is for equalizing room modes.

 

[fuzz092888]

Anti-Mode 2.0 can easily equalize whatever kind of roll-off of the sealed subs, the problem here is related to the signal level. When you set the headroom high enough, you'll lose signal level if you don't have enough amplification at the subwoofer.

It can easily do both, as you can manually set the headroom up to 20dB, which will allow you to boost 20dB without clipping. The problem is that you need to have enough amplification to compensate for the level loss of the headroom. You need to have powerful amplifier to do the required EQ to compensate for the roll off.

 

[TLS Guy]

Anti-Mode 2.0 can easily equalize whatever kind of roll-off of the sealed subs, the problem here is related to the signal level. When you set the headroom high enough, you'll lose signal level if you don't have enough amplification at the subwoofer.

It can easily do both, as you can manually set the headroom up to 20dB, which will allow you to boost 20dB without clipping. The problem is that you need to have enough amplification to compensate for the level loss of the headroom. You need to have powerful amplifier to do the required EQ to compensate for the roll off.

I will translate that for you Fuzz.

If you reduce the average level enough to provide equalization for your sub, it will do both functions without clipping. However your average level will be so low at that point, that no power amplifier will amplify the signal to power the sub. So I stand by my statement.

If you use the Anti-Mode to EQ sub and room, you will need a preamp between the Anti-Mode and your Crown. You will need 20 db of gain.

So my diagnosis and calculations were correct.

Since you have the Behringer unit, I would separate the sub EQ and room EQ functions. That will get you there. Your Crown amp has plenty of power, it just does not have the gain. Any power amp that did have the gain would likely have poor signal to noise.

So basically the Anti-Mode does not provide both functions in any useable manner with equipment that most people would have handy.

 

[fuzz092888]

I will translate that for you Fuzz.

If you reduce the average level enough to provide equalization for your sub, it will do both functions without clipping. However your average level will be so low at that point, that no power amplifier will amplify the signal to power the sub. So I stand by my statement.

If you use the Anti-Mode to EQ sub and room, you will need a preamp between the Anti-Mode and your Crown. You will need 20 db of gain.

So my diagnosis and calculations were correct.

Since you have the Behringer unit, I would separate the sub EQ and room EQ functions. That will get you there. Your Crown amp has plenty of power, it just does not have the gain. Any power amp that did have the gain would likely have poor signal to noise.

So basically the Anti-Mode does not provide both functions in any useable manner with equipment that most people would have handy.

They just sent me another e-mail saying that the hardware model I have has a max input voltage of 2V, but that if I swapped it out for the 2013 model it would have a max input voltage of 5V. Would that make a significant difference?

They also did not mention what kind of cost would be associated with that swap so ill probably end up doing what you said to do with the behringer regardless.

Thanks.

 

[TLS Guy]

They just sent me another e-mail saying that the hardware model I have has a max input voltage of 2V, but that if I swapped it out for the 2013 model it would have a max input voltage of 5V. Would that make a significant difference?

They also did not mention what kind of cost would be associated with that swap so ill probably end up doing what you said to do with the behringer regardless.

Thanks.

I doubt it would make a difference. 2V to 5V is only about 4db. In any event that don't specify the headroom on either unit and that is the most crucial aspect. If that unit had had full specs, we would not have wasted so much time on this. The problem would have been obvious immediately. I put all new units in the bench and find how much headroom I have.

Using the Behringer will be the best solution. If you put in a gain stage I would bet big money you would have a hissing sub, as the signal to noise ratio would be significantly downgraded. They don't specify an S/N which is another of their cardinal sins of omission.

So, set your Behringer to give +3db at 40 Hz, +9db at 30 Hz and +15 db at 20 Hz. Set the high pass subsonic filter at 20 Hz second order at 12db at 20 Hz.

Then listen to it, make sure it sounds reasonable. Then bring in the Anti-Mode and do room Eq. That is your best and most reasonable solution. It will be no different to using a sealed sub with built in Eq.

Now all you have to do is get the job done and post back.

 

[GranteedEV]

I don't think that thing is designed as a linkwitz transform. You will want to build your own analog circuit to perform those duties.

 

[TLS Guy]

I don't think that thing is designed as a linkwitz transform. You will want to build your own analog circuit to perform those duties.

Fuzz, I will have to look at that Behringer unit a little more closely. I will let you know if we can get it close enough.

 

[fuzz092888]

Fuzz, I will have to look at that Behringer unit a little more closely. I will let you know if we can get it close enough.

Ok, then I'll hold off on hooking up the Behringer and trying to get it set up. In the meantime I tried the latest suggestion and it didn't do diddly.

Here's what they said

TAs the problem is input clipping, you should set the volume of the Anti-Mode 2.0 Dual Core to it's maximum. The analog volume controller of the Anti-Mode 2.0 Dual Core is at the output, so decreasing it's volume to -20dB will just make the problem worse. Instead, when you maximize the volume on the Anti-Mode 2.0 Dual Core, you will have the same output level even with lower input signal level. So set the volume of the Anti-Mode to it's maximum, increase the input gain of the subwoofer if possible, make sure you have the input sensitivity at "low" and decrease the subwoofers pre-out level from the Onkyo. Keep the headroom at 5dB if it is the setting set by the automatic.

If the problem persists, meaning you can't get enough output level before the input of the Anti-Mode 2.0 Dual Core clips, then we have to swap the unit into 2013 hw edition that allows up to 5V input voltage instead of the 2V in 2012 edition.

 

[TLS Guy]

Ok, then I'll hold off on hooking up the Behringer and trying to get it set up. In the meantime I tried the latest suggestion and it didn't do diddly.

Here's what they said

That Anti-Mode gets no awards from. It has no headroom. A well designed unit should have headroom of 10db above line on the input and output. Putting the gain after the processor was perverse in the extreme. Don't waste your money on the newer unit.

Your Behringer is not ideal, but if you select graphic equalizer from the menu and set it as I described previously you will be OK. It is a 1/3 octave equalizer. The biggest problem is that it has no low pass filter function. Your anti-Mode does not either.

As I have said often, sealed subs are not easy to implement.

If you Eq the bass as I described you really do need a second order high pass filter somewhere between 20 and 25 Hz, to prevent driver damage, if you intend to use the sub for high spl.

I have a lot on my plate right now. I got back from the UK Sunday after my father's funeral. I'm back at Benedict now. I have to get the system I donated to Afterlife 2 off, as well as go through all the accumulated mail.

I will see if there is an off the shelf unit that we could use or adapt when I have time. Otherhwise we need to design and build a custom unit. Properly set up you should have an impressive sub. It won't get that deep bass you are looking for without Eq, but that goes for ALL sealed subs.

 

[fuzz092888]

That Anti-Mode gets no awards from. It has no headroom. A well designed unit should have headroom of 10db above line on the input and output. Putting the gain after the processor was perverse in the extreme. Don't waste your money on the newer unit.

Your Behringer is not ideal, but if you select graphic equalizer from the menu and set it as I described previously you will be OK. It is a 1/3 octave equalizer. The biggest problem is that it has no low pass filter function. Your anti-Mode does not either.

As I have said often, sealed subs are not easy to implement.

If you Eq the bass as I described you really do need a second order high pass filter somewhere between 20 and 25 Hz, to prevent driver damage, if you intend to use the sub for high spl.

I have a lot on my plate right now. I got back from the UK Sunday after my father's funeral. I'm back at Benedict now. I have to get the system I donated to Afterlife 2 off, as well as go through all the accumulated mail.

I will see if there is an off the shelf unit that we could use or adapt when I have time. Otherhwise we need to design and build a custom unit. Properly set up you should have an impressive sub. It won't get that deep bass you are looking for without Eq, but that goes for ALL sealed subs.

I'm in no rush, I just appreciate the help. I do want to point out that the antimode does have an infrasonic filter that can be set at 10, 15, or 20hz. The antimode also can implement low pass filters at selectable slopes and has PEQ filters. I don't know if you mean that these need to be implemented before or after the antimode, but it seems like this is what you're talking about, at least from my limited knowledge.

 

[TLS Guy]

I'm in no rush, I just appreciate the help. I do want to point out that the antimode does have an infrasonic filter that can be set at 10, 15, or 20hz. The antimode also can implement low pass filters at selectable slopes and has PEQ filters. I don't know if you mean that these need to be implemented before or after the antimode, but it seems like this is what you're talking about, at least from my limited knowledge.

In that case use the Behringer between the Anti-mode and the Crown with the settings I have given you. Engage the subsonic filter of the Anti-Mode at 20 Hz. The do the auto Eq and see what happens.

I do have Linkwitz transform spreadsheets for designing circuits to equalize passive subs. That is long term your best solution.

 

[lsiberian]

In that case use the Behringer between the Anti-mode and the Crown with the settings I have given you. Engage the subsonic filter of the Anti-Mode at 20 Hz. The do the auto Eq and see what happens.

I do have Linkwitz transform spreadsheets for designing circuits to equalize passive subs. That is long term your best solution.

that is quite a useful spreadsheet.

 

[fuzz092888]

Inserting the behringer seems to have done the trick. I also contacted antimode and they said they would swap out this unit for the newer one free of charge, so I may take them up on that just for the heck of it.

I'm definitely interested in the spreadsheets, since you mentioned it is the long term best solution and I doubt this will be my last passive sub. Thanks for all the help guys, I really appreciate it.

 

[GranteedEV]

My condolences for your loss, Dr. Mark.

 

[fuzz092888]

Just a quick update. Found something funky with the driver, a bit of scratching with pressed upon so I ended up sending it in for repairs under warranty. The thing hasn't arrived yet so no word on what exactly is wrong. Perhaps this contributed to all the other problems as well, or is a result of the problems. Oy vey.

 

[GO-NAD!]

Just a quick update. Found something funky with the driver, a bit of scratching with pressed upon so I ended up sending it in for repairs under warranty. The thing hasn't arrived yet so no word on what exactly is wrong. Perhaps this contributed to all the other problems as well, or is a result of the problems. Oy vey.

That's a drag.

 

[fuzz092888]

Well, just as a quick update to anyone out there, I got the sub back from the repair work. It had a different dust cap, which I wasn't thrilled about since I liked the look of the other one better, but I guess I'll live. I went to great lengths to ensure it was broken in before I really started to push it, probably about 24 straight hours of tone sweeps, 2 movies, a couple TV shows, then another round of sweeps for 12 hours. Overkill, but I needed to make sure that if anything else happened there was no doubt it wasn't my fault.

Anyways, after all that the thing sounds fantastic. I haven't run any room correction yet, but I have added a 12 db/oct boost with the DEQ from 40hz down. I believe the infrasonic filter is on as well courtesy of the antimode. I am extremely happy with how it turned out and hope it sounds even better after RC.