Hey everyone,
I have a full acoustic room treatment arriving mid-August (bass traps, rockwool wall panels, scatter plates, etc.)
I have Pensil 11's with MAOP 11 drivers, currently with about 330g of acoustic stuffing in each box (which is about about 66% of the recommended max amount, according to a post I read here a while back from Dave, who I believe said he found 50% ideal? Apologies if I'm misremembering)
So my question:
How is acoustic stuffing generally adjusted based on room size and acoustic treatments? Should I be removing acoustic stuffing if my room has better treatment?
Thanks in advance!
I have a full acoustic room treatment arriving mid-August (bass traps, rockwool wall panels, scatter plates, etc.)
I have Pensil 11's with MAOP 11 drivers, currently with about 330g of acoustic stuffing in each box (which is about about 66% of the recommended max amount, according to a post I read here a while back from Dave, who I believe said he found 50% ideal? Apologies if I'm misremembering)
So my question:
How is acoustic stuffing generally adjusted based on room size and acoustic treatments? Should I be removing acoustic stuffing if my room has better treatment?
Thanks in advance!
Greets!
Probably, though historically, one optimizes the cab in at least 2pi space, i.e. setting outside in a large 'flat enough' field or parking lot and modding the room to suit, which is to say all room modes are damped out to at least the 3rd harmonic/-24 dB or make the room some form of recording studio playback: The SOS Guide To Control Room Design
In theory then, and ignoring alignments meant to be well stuffed, the well designed vented speaker will only need minimal wall damping on its top, one side and back with any fine tuning left to 'critically' damping its vent to remove any hint of 'hangover'/'boom': Click Test: Click Test | GM210 | Flickr
Done your way, recommend starting with an empty box or at least just the minimal amount around the driver for early reflections since absolutely everyone that's gotten back to me re my designs I've done for them said they had to remove most of even the minimal amounts HR and MJK's software simmed, ie. if it was a smooth, ripple free sim, it was too much and several of the ~16 - 30 ft^3 [ML]TL cabs done for Altec/JBL 15" drivers removed it all except for redoing the click test.
Probably, though historically, one optimizes the cab in at least 2pi space, i.e. setting outside in a large 'flat enough' field or parking lot and modding the room to suit, which is to say all room modes are damped out to at least the 3rd harmonic/-24 dB or make the room some form of recording studio playback: The SOS Guide To Control Room Design
In theory then, and ignoring alignments meant to be well stuffed, the well designed vented speaker will only need minimal wall damping on its top, one side and back with any fine tuning left to 'critically' damping its vent to remove any hint of 'hangover'/'boom': Click Test: Click Test | GM210 | Flickr
Done your way, recommend starting with an empty box or at least just the minimal amount around the driver for early reflections since absolutely everyone that's gotten back to me re my designs I've done for them said they had to remove most of even the minimal amounts HR and MJK's software simmed, ie. if it was a smooth, ripple free sim, it was too much and several of the ~16 - 30 ft^3 [ML]TL cabs done for Altec/JBL 15" drivers removed it all except for redoing the click test.
Hi Dave!
I sent you a couple of emails w/ no response. Is you email still messed up? Please let me know the status of these drivers.
Thanks!
MG
Well, I finished my Sea Stacks. They sound great. And they sound awful.
The good: Very realistic and natural. Really excellent on acoustic instruments and vocals. Detailed. Good imaging.
The bad: The bass is a mess. Boomy, flabby, overpowering. Almost unlistenable.
This is not the speakers fault, I think. I had planned to use these in a large living room, but due to a domestic situation I had to move them to a small bedroom. They completely overpower the small room.
I've played with a bit of stuffing in the boxes. It helps, but it's not enough.
So, what to do?
Would one of the smaller ported designs for the 11ms work better in a small room? Nostromos? Some of those Onken types? I have enough birch ply left over to build something like that.
Or am I better off starting from scratch, new drivers and all, and building something meant for use in a small?
The good: Very realistic and natural. Really excellent on acoustic instruments and vocals. Detailed. Good imaging.
The bad: The bass is a mess. Boomy, flabby, overpowering. Almost unlistenable.
This is not the speakers fault, I think. I had planned to use these in a large living room, but due to a domestic situation I had to move them to a small bedroom. They completely overpower the small room.
I've played with a bit of stuffing in the boxes. It helps, but it's not enough.
So, what to do?
Would one of the smaller ported designs for the 11ms work better in a small room? Nostromos? Some of those Onken types? I have enough birch ply left over to build something like that.
Or am I better off starting from scratch, new drivers and all, and building something meant for use in a small?
To echo/expand on Jeff’s comments, there are several factors at play in any system, amp and room definitely amongst them.
Just what are the room’s dimensions?
Sorry, I can’t remember exactly how much of what type of acoustic damping I used on our build, but even with as I recall very little break-in, they had no problems with bass in my 420sq ft room, powered by either the Onkyo TX NR818’s internal amps or any of several outboard units. Dave likely had an even wider range of amp types and topologies in rotation for his own listening.
Just what are the room’s dimensions?
Sorry, I can’t remember exactly how much of what type of acoustic damping I used on our build, but even with as I recall very little break-in, they had no problems with bass in my 420sq ft room, powered by either the Onkyo TX NR818’s internal amps or any of several outboard units. Dave likely had an even wider range of amp types and topologies in rotation for his own listening.
Damping factor: a bastardsization of amplifier Rout.
Yes, typically an SE tube amplifier has highish Rout which means the loudspeaker will need have more acoustical/mechanical damping than a more typical low Rout Class AB SS amplifier.
Your description of your issues suggest that the intection is sufficient to cause issues. And then the room…
dave
Small pushes room issues up in frequencies and can excerbate really LF issues.
You will need to juggle a bunch of contributing factors.
dave
Alright. I've been experimenting all afternoon and I've got it figured out. It's definitely a combination of the tube amplifier producing awful bass in the lowest octaves, and the small room enhancing and exaggerating all that awful bass. It's the worst of both worlds.
With a SS amp the bass is clean and tuneful. In the small room the bass is still way too loud, but it's not ugly bass, just excessive. If I move the speakers to a large room and use the SS amp everything's peachy.
Extra stuffing in the enclosures didn't really help. What I thought was improving the bass was actually just attenuating it. Zero bass output is better than ugly bass output, but it doesn't really solve the problem.
And that leads me back to my original problem: What do I do now?
I'm leaning towards moving the 11ms drivers to a small vented box like the Nostromo. The small BR boxes don't have nearly as much deep bass output as the big MLTL's, right? I think these drivers would sound great if not for the huge bass output overpowering my tiny room. Well, that and a new amp.
With a SS amp the bass is clean and tuneful. In the small room the bass is still way too loud, but it's not ugly bass, just excessive. If I move the speakers to a large room and use the SS amp everything's peachy.
Extra stuffing in the enclosures didn't really help. What I thought was improving the bass was actually just attenuating it. Zero bass output is better than ugly bass output, but it doesn't really solve the problem.
And that leads me back to my original problem: What do I do now?
I'm leaning towards moving the 11ms drivers to a small vented box like the Nostromo. The small BR boxes don't have nearly as much deep bass output as the big MLTL's, right? I think these drivers would sound great if not for the huge bass output overpowering my tiny room. Well, that and a new amp.
On second thought, maybe I should build a small vented box for the 7ms instead. If I don't need/want the deep bass, what's the point of the larger 11ms driver? The 7ms is supposed to be a tiny bit better in the mids and highs, I hear.
The cost of the new drivers is no big deal. The money I'm saving not buying veneer to finish the giant Sea Stacks more than makes up for the cost of a pair of new 7ms drivers. Madisound even has them on sale now...
The cost of the new drivers is no big deal. The money I'm saving not buying veneer to finish the giant Sea Stacks more than makes up for the cost of a pair of new 7ms drivers. Madisound even has them on sale now...
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How low a box goes depends on Fs Qt and Vas.
But if one considers Hoffman's Iron Law and we consider that the A7ms is not as efficient, and the optimum box is the same volume, one has to get lower bass from the smaller driver.
The main reason is th every low Qt of the A11ms. Perhaps a trade-off to get the sensitivity up.
Now i hope these sims don’t make a liar of me. Edit: they only show that they are really close sealed.
Now the sealed sims don’t say anything about vented wizardy and keep inmind optimum vented volume is close to the ).58 sealed box.
dave
But if one considers Hoffman's Iron Law and we consider that the A7ms is not as efficient, and the optimum box is the same volume, one has to get lower bass from the smaller driver.
The main reason is th every low Qt of the A11ms. Perhaps a trade-off to get the sensitivity up.
Now i hope these sims don’t make a liar of me. Edit: they only show that they are really close sealed.
Now the sealed sims don’t say anything about vented wizardy and keep inmind optimum vented volume is close to the ).58 sealed box.
dave
Attachments
OK, looking at the sims, the difference is not all that significant, maybe 2 more hz for the A7ms when nboth mounted in optimum miniOnken,
Small enuff that differences in alignemtn could make thigns quite different.
At least with Nosdtromo you can mostly adjust for the ampifier's highidh Rout. Less bass wilnot excite the bass modes inyour room (or do so less)
dave
Small enuff that differences in alignemtn could make thigns quite different.
At least with Nosdtromo you can mostly adjust for the ampifier's highidh Rout. Less bass wilnot excite the bass modes inyour room (or do so less)
dave