[baniels]

I built this sub about 5 years ago. It has suited me pretty well over the years. I picked up a BFD 1124 some years ago and never actually made use of it. I remember doing some EPROM swap in it, buying the midi/usb cable, but then I never actually used it. I think getting married, buying a house, and having a kid had something to do with it.

Anyhow - so I'm sort of back in the thick of the hobby again now... my new mains will be done soon so I'm thinking I ought to get my subwoofer tamed. Up to now I haven't had any very nice mains, so I haven't been as motivated to squeeze the sub for all it's worth. I'm not even bothering measuring the mains I have now - and see no use to.

Truth is I'm already thinking of a new sub - but it may be some time before I can do that. In the mean time, I will post my graph and see ask for thoughts from the crowd. I haven't tried moving the sub - my listening room is also our living room, and the toys and play area for my 2 year old don't give me a lot of options.

Room has half vaulted ceilings, open to the kitchen and a hallway which leads to the upstairs. The sub box is between my a/v cabinet and the front right speaker. The 12" driver is facing out and the 15" PR is facing (and about 4-6 inches from) the wall.

Using an EMM 6 from CSL and an M-Audio FireWire Solo.

So... I'm not sure what I'm asking for - maybe just some thoughts from those who have looked at more of these graphs than me. It might be worth noting that I can probably cross my mains pretty low (50 or 60 easily I believe), perhaps making that ~80 hz null yikes less of an issue. Or maybe the mains will be subject to the same room influence? I won't know until I have them finished and measurable.

 

[informel]

OK, I'm not an expert (the expert will answer later I'm sure)
but give it a try with your main, after all, the hardest thing to reproduce is solid bass and will give your main a chance and they might be able to fill in that null at low volume, (at high volume, your main will probably give up).
You might be pleasantly surprise.
I was when I tried my Velodyne DD-15 with not so good main (not enougth money left to upgrade the rest of the system)

 

[Zeitgeist]

Is that Un-EQed and just the graph from REW?

The response doesn't look bad. Couple use a few minor filters.

A couple dips look like they might be room modes..

 

[baniels]

Yes - this is with no EQ. Sound card --> filter-free BFD --> 500w Bash plate amp.

Well, I'm glad to get some validation - I'm pretty sure the 80 and 160 hz nulls are room modes. I will experiment with some filters - when I let REW do the job it wants to give me all 12 of them and I know that's not a good thing.

Lacking confidence in making my own - but I'll go ahead and try and post here for comment.

Is that Un-EQed and just the graph from REW?

The response doesn't look bad. Couple use a few minor filters.

A couple dips look like they might be room modes..

 

[Wayne A. Pflughaupt]

You’ve got good extension with that sub. :T If other locations are available, another location might work out that null at 80 Hz. So experiment if you can. But it looks like you have no crossover in operation? Make sure it’s engaged before you do any equalizing. That's why we usually recommend sending REW's sweeps throuh your AVR, so its crossover gets in the signal chain.

when I let REW do the job it wants to give me all 12 of them and I know that's not a good thing.

That usually means your Target is set too low. Based on your graph, I’d set it at 75-76 dB.

Regards,
Wayne

 

[baniels]

Thanks, Wayne. I'll try changing upping the target.

You're right - no crossover in the chain. I went straight into the sub. I'm basically trying to see where I stand, and get to know REW a little before I get my mains finished. Once they are done I will do it all again with fewer unknowns about my approach (hopefully). But it makes sense to do what you say and measure with the crossover in place.

I don't have too many placement options - but I could definitely try moving it to the other side of the tv. Wife and boy are out for a week later this month and with luck I'll have my mains done with ample time to experiment in a quiet house.

 

[baniels]

I just finished my mains a few nights ago. WOW - they sound fantastic!

I've never had full range speakers before. I've had to rely on a sub for decent bass output of any type.

I'm going to give the speakers a few weeks of use to break in before I take the time to do measurements, house curve, etc. But I have noticed something that is either peculiar, or illuminates my ignorance. There are two parts.

I ran Audyssey on my Onkyo TX-SR805. Not surprisingly it set my mains to Full Band. The 805 has an option for "Double Bass" where it sends LF to a sub even if you have full range mains (on a side note, I'm not sure where it decides to cross/double up in this case). But that is only enabled by the user - ie Audyssey won't make that decision for you and I did not enable this.

This is part 1 of my question: With this setting, when listening to a 2 channel source, with the playback mode set on Stereo on the Onkyo, shouldn't I expect no signal to be sent to the subwoofer??? My sub was definitely getting a signal. It seems so strange to me that now that I write this I am having doubts - it's just too odd. But I know it happened :huh:

Part two is about the sound when setting the mains intentionally to cross over to the sub. After Audyssey, I manually adjusted the levels so that all channels are at 75 db on my spl meter, then changed the mains from full band to cross at 60hz.

The Onkyo has a Direct mode - which disables Audyssey EQ and the sub crossover (so 2 channel source -> 2 channel output). I was toggling between the Direct mode and Stereo mode, which activates the subwoofer. I found that when I was in stereo mode, the LF output overall was very lean compared to running just the mains.

Considering that I have decent output with the sub, and I'm crossing a good touch below that null, what would account for this? I even tried running the sub 4-6 db hot and it still seemed lacking.

Any thoughts?

 

[baniels]

After doing some (re)reading on Audyssey, particularly the target curve in my device, it could be that Audyssey is not giving a desireable output. Not a lot, but some of the music I listen has some pretty heavy bass.

Because the Oppo won't output 2 channel to 2.1, perhaps I should still be glad that I own an Outlaw ICBM :T. I will dig that out. Because it will not be doing anything other than acting as a crossover between the mains and the sub, I can run 2 ch. analog out of the Oppo and avoid anything else Audyssy is doing to the signal in addition to crossing over to the sub.

EDIT: Looks like my Oppo 93 can handle this all on its own. ICBM will continue to gather dust.

 

[JohnM]

Fabulous job on those! :T

 

[baniels]

I'm thinking now to get a miniDSP. From what I have read it will offer me more flexibility and the use of biquads will allow for a steep high pass in my <20hz danger zone.

I've seen this idea thrown out there, but I can't seem to find a fully developed conversation on it.

Option 1 (traditional)
Buy MiniDSP 2x4
Cross mains/surrounds at XX hz and feed crossed content + LFE content to MiniDSP.
All content EQ'd per filters by way of calibrations and REW

Option 2 (questionable)
Set mains to Large +LFE - tell receiver that I have no sub.
Preouts for R/L go into MiniDSP
MiniDSP manages the crossover between mains and sub, sending L/R content to amp, and low content to sub.

I guess the question is whether I'm correct in thinking that this would allow for better integration of sub and mains, since I'm not limited to the receiver's xover slope (at whatever point I choose from the options of 40/50/60/70/80/90/100/120/150/200).

And on an side note - is there a reason to choose the 2 way Advanced 21 plugin over the 2way Advanced? Or a reason not to choose it, assuming I go with the traditional setup from Option1 above?

 

[patchesj]

The miniDSP is a very nice tool, but to be honest I think you can get where you want with some tweaks on the Onkyo and the BFD. Did you run audyssey with the BFD disabled? Keep in mind that audyssey is going to try and get your sub flat with the mains, to most people this sounds weak. You can add a house curve to the BFD (and have a setting without one too) to make up for it.

 

[baniels]

You bring up a good point. I don't use Audyssey. I use it set my speaker distances and levels. I hate don't like what it does to the sound, so I turn off Audyssey EQ. My Onkyo (805) only has the standard Audyssey curve - flat is not an option. It makes my music sound lifeless.

I haven't used the BFD yet - just ran the above plot with the sub alone.

 

[baniels]

Svendson just made a very good point his reply to my PM (he had been poking around this idea, and I sought to find out if he ever did it).

In this configuration (5.0 with mains as full+LFE), there may not be a way to increase the mix level of the LFE without increasing the <crossover point content from the mains.

So let me reduce my question to this...

Any reason to choose one over the other between the 2 way Advanced 21 and the 2way Advanced plugin?