So here’s a progress report on my sub project. After moving and adjusting and adjusting and moving and playing a range of recordings - thanks VERY MUCH to those of you who suggested cuts - the sub is settled smack dab halfway between my main speakers. With my relatively small room size, it was really only one frequency - around 40 Hz - that seemed to generate a standing wave, so putting it at the 1/3-from-front-wall position gave me the clearest place to get things under control. It’s also quite a balancing act to figure out how much to let the sub do its thing and still let my Vandersteens do their thing, which I’m pretty happy with how well they’ve been doing all along. I might try moving the sub to a different place on that plane, so I don’t trip over it so easily, but I think it’s dialed in.
The next project is to re-do my room correction DSP to see what that does.
Hi all. I ran into a recording last night that is really great in my opinion for subwoofer evaluation. Earlier this year I discovered the Israeli jazz clarinetist Anat Cohen - phenomenal player. I learned that she has two brothers who also play jazz. One is trumpeter Avishai Cohen. So a few days ago I was searching for recommendations of jazz recordings featuring a full-range of bass, and there was a listing for a recording by Avishai Cohen. I thought maybe he recorded with a quartet that had a great bassist… until I discovered there are TWO Avishai Cohens in the jazz world. I guess next I’m going to find another Thelonious Monk? Anyhow, the BASSIST Avishai Cohen is really good - he’s been around for a number of years. His latest recording is an in-studio live session, and wow, the bass is incredible, as is the rest of the recording. It also challenges the musicality of my system where the sub stuff isn’t just effect, it can be heard as notes. Since he’s all over the instrument, it’s a great chance to hear how everything is working down there.
Glad you got something from it. I’m often hestitant to recommend music I like, because, well, a lot of what I like other people find strange, including modern “classical” music and avant-garde jazz. If you like more progressive jazz and Avishai Cohen, he was a member of a fairly short-lived group called Origin under the leadership of Chick Corea. I had the chance to hear them a few times in concert and they were brilliant. A great album of theirs on Qobus is called Change.
For a part of the marketing launch of our new subwoofer, I’m going to do a youtube video series on subwoofers and subwoofer setup. I would love some input from the forum (can start a new thread on this, but wanted to put a post here where this is lot of action on the topic). I would like to get some input on questions that you guys would like to have covered from the basics to very advanced. Technology, setup, system configurations, anything. Would love to hear your feedback and ideas. .
I think an explanation of the benefits and drawbacks of continuous phase adjustment versus toggle switch between 0 and 180 degrees would be a good topic to cover.
Whatever you do, please come up with a better way to set it up optimally than “push it around the room while using a dumb bass track and just your ears to determine if it’s set up correctly”.
Further to what adifferentpaul wrote, I’d like to hear your opinion on connection to preamp versus connection to main amp. My subs don’t have specific high-level inputs, they have 3, switchable settings of
0.5V (or less) - sub sensitivity of +6dB
1.0V - sub sensitivity of 0 dB
2.0V (or more) - sub sensitivity of -6dB
The manual doesn’t explicitly call them ‘low-level’ or ‘high-level’ inputs.
Hi Chris. Since I’m still involved in setting mine up, here are some things fresh on my mind that others haven’t mentioned directly:
How best to define your goals - do you want kick-ass bass or do you want to just make sure you’re fully experiencing what’s on the recording that you should be hearing?
Said already, but emphasizing that what is the best way to determine placement. My REL instructions pretty much say to put it in the corner and move out from there, never implying that sticking it anywhere OTHER than a corner might be best
Advantages of multiple subs
Considerations of using DSP room-correction software to bring the whole system better in line with what is truly ON the recording, as opposed to just having it sound the way you THINK it should sound.
I’m sure I’ll think of others, but that’s it for now.
These connection options are all “low level”. A high level input is meant for a speaker level signal that has ~25 dB of gain.
As long as you have a preamp with enough pre-outs etc, a line level input is great.
If you want to make a speaker level connection to a line level connection, it is literally just a couple of resistors added to an RCA cable to knock the level down to line level, if you want to wire off your speakers or amplifiers for convenience and aren’t using a multi-channel preamp/processor with bass management.
Thanks for the reply Chris. My ‘preamp’ is a DSDAC Mk 1 so I use the ‘>2V’ setting and short XLR ‘Y’ cables. I use Transparent Reference cables from the ‘Y’ cables to my mono blocks and subs. One day I’ll try your resistor idea and see how that compares.
Thoughts on placing subs raised off the floor, like on the ASC sub trap stand. Relate this to potential benefits of placing sub drivers in the same vertical and horizontal plane of main speaker driver voice coils so wave timing or phase is similar. Sub stacks seem to benefit some from this.
More discussion on double bass arrays and their related room treatment issues. Should the side walls avoid deep panel treatments and stay more reflective, so waves pass easily over the listening area, or the backwall be set up more absorptive to complement the cancellation effect that inverting or adjusting the phase approximately 180 degrees the rear wall sub tries to achieve.
With a DBA, using XLR balanced line outs from a preamp with two outputs, is it best to have one sub in front use the right channel output and the rear sub left channel for example, as opposed to switching the preamp sub outputs to mono for both (if the crossover is set below say 60 hz to avoid any directionality).
Chris or anyone please help me understand “phase”. To me, phase is a relative term. When the left and right speakers are dealing with the same content (say a mono source) it is critical that the be in phase relative to each other. And even then, if you are not midway between the speakers, their sound waves will not arrive in phase except by chance for certain frequencies. On the other hand, if there are two guitars, one only in the left channel and the other only in the right, the phasing of the speakers would be irrelevant. After all, the guitars weren’t in phase to begin with. So to the question of a sub about phasing: if there is only one sub and it’s not midway between the speakers, it can never be in phase with both. Now with two subs, their relative phase would matter. Where am I misthinking this?
This is a good topic for a video since, below a couple hundred hertz, sound waves don’t freely propagate (as it would in free space) in-room and there is more complex modal behavior - positive and negative pressure modes geometrically in the room. In short, phase can be different for each of these modes. We can discuss this more, but you might play around with a room mode simlator in REW or visualization app like this to understand it.
