What do you think?

[logan00]

Here are the graphs of my room. THe first graph is of my previous sub, the next is of my dual HSU HO's without eq and the final one is of my dual HO's with eq. What do you guys think?

[brucek]

Looks pretty good. You might bring that peak at 20hz down a bit though.......

[logan00]

Since I have dual HSU HO's I decided to try 1 in max ouput and 1 in max extension (previously I had both in max extension), after filtering this is my new response.

How does this look, any recommendations?

[Wayne A. Pflughaupt]

I think I’d try to get up those two relative lows between 40-60 Hz. I had a 4-5 dB peak in that area that was much narrower than that, and I could hear it. That was with music, though. If your primary use is movies, then you’re fine with what you have there.

Regards,
Wayne

[logan00]

This graph is the best I can do, aside from boosting the frequencies, which I refuse to do. Also, my listening is 99% movies/games and 1% music.

Also, how does the input level affect the output? Right now I have my sub level in my receiver set at -9.5db and the volume on the subs tuned so that they all add up to 77db on my spl. I initially had the level at -7.5db, but I found that the bfd seemed to clip easier. If I raise the reciever's volume to -11.5db, and increase the sub's volume then it didn't seem to clip at my normal listening volume, but I chose to stay at -9.5db on the receiver. The reason I am asking is I want to know if the input level affects how loud the sub will play during a movie as I increase the master volume on the receiver. Does the bfd restrict the maximum db that my subs will produce in room? For example, I watched a scene from a movie and with the subs only playing I got 108db on my spl at -8. When I increased the receiver's volume to -6 I still got only 108db on the spl, shouldn't it have increased?

Thanks

[brucek]

The reason I am asking is I want to know if the input level affects how loud the sub will play during a movie as I increase the master volume on the receiver. Does the bfd restrict the maximum db that my subs will produce in room? For example, I watched a scene from a movie and with the subs only playing I got 108db on my spl at -8. When I increased the receiver's volume to -6 I still got only 108db on the spl, shouldn't it have increased?

The BFD has a maximum input level (when using the -10dBV switch setting) of ~1.26 volts. The BFD is a unity gain device and so the output will track to the same maximum 1.26 volts. (Cut filters will reduce the output at their respective frequencies and gain filters will still be constrained by the 1.26 volts limit).

That voltage of 1.26 volts is consistent with most retail equipment and will drive most subs to maximum outputs.

If you feed the BFD more than the maximum input level, it will clip and the RED LED's will indicate so. You have reached the end of the ability to increase the output level of the BFD beyond that point.

If the RED LED's aren't indicating clipping, then you still have 'travel' before reaching the limit. If your sub does not increase its SPL level when in this normal operating range of the BFD, then it's because you've reached the limit of your subwoofer and not the BFD. The sub is compressing.

brucek

[Wayne A. Pflughaupt]

What brucek said. Many if not most subs with digital BASH amplifiers have built-in limiting. In other words, at a certain point they’re just not going to put out any more. This is to prevent the driver from bottoming out.

Regards,
Wayne

[logan00]

So is it better to have an input level that is closer to 0 on the receiver or further away? Right now I am at -9.5, should I stay where I am or increase this level and turn down my subs volume knobs. The input level is the only thing that I am uncertain about the bfd. I believe my subs have more headroom then the bfd is feeding them so I want to make sure that I have the ability to use all of it.

[Otto]

Hi logan,

How close are you to clipping the BFD's input? That's what determines how to set the sub level on your receiver.

BFD User Guide wrote:

On the top right front of the unit you will see the "IN/OUT" button. Press and hold this button for a moment until the button light blinks. You are now in the "BYPASS" mode with no filtering active. You can only monitor the setting of the input level in the "BYPASS" mode. The input level is monitored by the LED's in the far left section of the display window. If the unit is not in the "BYPASS" mode then the LED's will monitor the "output" level.

Crank up something to what you think will be pretty much as loud as you would ever want to play it. Choose something with lots of bass; many people use WOTW's "pods emerging" scene, Finding Nemo's "Darla tapping" scene, Master and Commander's cannons and so on. Follow the instructions above, but you may want to turn your sub's amp off, so that you don't damage your sub during the test. You don't really need to hear it; the important thing is to monitor the LEDs on the BFD.

As you run this bass heavy scene, set your receiver's sub out level such that the red LEDs on the BFD never or very rarely light. A little clipping isn't going to be the end of the world, but you don't want to be running up there frequently. I'll usually push it a little, as I won't be listening at this "max volume" for 99% of the time.

Once you figure that out, you can pretty much leave the sub level on your receiver alone, and your input level to the BFD is set. That said, I would certainly allow the option to tweak sub level from the receiver based on program material. As you know, some movies/music are recorded so HOT in the bass region that you simply must turn it down. Likewise, some program material is lacking bass and you have to turn it up, otherwise it just sounds very thin. I do this all the time, and usually I adjust by no more than 3 dB in either direction (but I'd go more if I felt like it). Remember, if something's really heavy in the bass department, then you would potentially be clipping the input to your BFD earlier, so it would be appropriate to turn down. Just keep in mind where your initial sub level was, and hang around there.

That's pretty much how it works for setting up the input level to the BFD. After that, do your filters and adjust overall levels to match mains as desired.

[logan00]

Thanks Otto, perfect explanation, time to go and tweak some more