6sx7,
Good to know that the F6 clones are up and running. Look like you are enjoying the combo. 🙂
Have fun!
Good to know that the F6 clones are up and running. Look like you are enjoying the combo. 🙂
Have fun!
I’m enjoying my Halcyons every day, but I’m still hearing a little too much bass boominess. Every time I add more stuffing, it gets better and then later it starts creeping into my consciousness, but at a lower level than before. Does anybody have any other ideas? These speakers have great tone, great “soundstage” characteristics, and great dynamics. No subwoofer needed, but a touch of boominess remains.
I have found the same. I was in e-mail correspondence with zman01 and was going down the path of trying F5 boards in my 1stW clones but got into a thinkin' period. Been considering several options:
1. close the port
2. F5 boards
3. biamping w/ active crossovers and some eq.
4. a 10p open baffle design.
But I've been in quite the thinkin' period that I haven't even done the simple experiment of closing the port.
1. close the port
2. F5 boards
3. biamping w/ active crossovers and some eq.
4. a 10p open baffle design.
But I've been in quite the thinkin' period that I haven't even done the simple experiment of closing the port.
Try dampint the vent. I like stiffidh open cel foam for this. Keep putting disks in until it calms down enuff.
dave
dave
You likely need to lengthen the port. Boominess, room issues aside, is usually caused by a peak before rolloff. Add 1-2" to the length and see what you get in results. It could be differences in actual woofer T/S versus the drivers used in the design stages.
Damping the port inner perimeter only reduces the turbulence and some of the output. Since it is reducing the effective diameter, the tuning will lower a small fraction.
Placing discs in the port of foam that partially blocks the terminus will change it to an at least slightly Aperiodic result and likely reduce the extension by a huge margin. Being an MLTL, I'm not certain this is the best option.
The last option is trying different damping material with higher effectiveness. If you are using standard polyfil it might not be as efficient as necessary. Using some Ultratouch, or some other denser fill may alleviate the issue and keep the tuning intact if that is not to blame.
Later,
Wolf
Damping the port inner perimeter only reduces the turbulence and some of the output. Since it is reducing the effective diameter, the tuning will lower a small fraction.
Placing discs in the port of foam that partially blocks the terminus will change it to an at least slightly Aperiodic result and likely reduce the extension by a huge margin. Being an MLTL, I'm not certain this is the best option.
The last option is trying different damping material with higher effectiveness. If you are using standard polyfil it might not be as efficient as necessary. Using some Ultratouch, or some other denser fill may alleviate the issue and keep the tuning intact if that is not to blame.
Later,
Wolf
Yes, it pushes the speaker aperiodic. It won’t really affect the extention. But that the vent/restricted terminus is not tuned low enuff ad there is a peak. There would have to be significant diferences in the drivers form when Curt originally designed them as inan ML-TL the box dominates.
I have done just this (well in a slightly different way) with almost all of our specific impementations of Scott’s ML-TLs with good results.
Worth exploring. Or it could just be that your existing damping needs more teasing.
dave
The damping I’ve been using is Acousta-Stuf. Is that as good as Ultratouch?
Dave, was that “stiff-ish open cell foam”? What would be an example of that? The cylindrical part of the port is only about an inch long, so not too many disks will fit. Maybe if I try Wolf-Teeth’s idea of lengthening the port, I’ll have more room for disks of open cell foam if needed. Does that make sense?
Dave, was that “stiff-ish open cell foam”? What would be an example of that? The cylindrical part of the port is only about an inch long, so not too many disks will fit. Maybe if I try Wolf-Teeth’s idea of lengthening the port, I’ll have more room for disks of open cell foam if needed. Does that make sense?
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Astuf should be dense enough, so it's hard to say if something else would be better/worse.
Is there any lining or just stuffing? I've known of some builds where the foam lining allowed transmission of waves around it, negating the stuffing completely since it was bypassed. Not my build, but the person said removing his carpet padding lining and not the stuffing made a world of an improvement in the sound.
I would try lengthening the port should the above not be involved.
Is there any lining or just stuffing? I've known of some builds where the foam lining allowed transmission of waves around it, negating the stuffing completely since it was bypassed. Not my build, but the person said removing his carpet padding lining and not the stuffing made a world of an improvement in the sound.
I would try lengthening the port should the above not be involved.
Perhaps the clue here is:
"Every time I add more stuffing, it gets better and then later it starts creeping into my consciousness, but at a lower level than before."
Could it be that the stuffing is settling with use, allowing gaps that are not impeded by the stuffing?
I used polyfill for my stuffing. My experience with Acusta-Stuff is that is is somewhat denser and less 'springy' than poly, so changes in the amount of stuffing by weight and or settling factors may suggest additional care in installation would be required.
I still play my Halcyons from time to time and do not notice any boominess, however it was designed with the original SB17NRXC35-8-UC, which SB Acoustics later replaced with the SB17NRX2C35-8. While the T/S parameters suggest they are very close to a drop in replacement, some minor variations in tonality are possible.
As you noted, there is not a lot of length for foam in the port so any foam there will be unlikely to make a significant difference. The design is tuned to roughly 25 Hz, with the modeled plots of the MLTL suggesting no ripple at the knee of the tuning frequency. I would guess adding a longer port would be unlikely to affect a positive change. -On the other hand, it is easy to try.
I'd suggest the best way to deal with the boominess is to continue adding stuffing. While my original design did not use stuffing in the central chamber, certainly there is a lot of potential for added stuffing there is need be. Polyfill is cheap. It may be worthwhile experimenting with variations of the type of stuffing, positions, and weight/volume to find your sonic nirvana.
Another possibility would be the 'new' SB17's (or this product run) may be slightly more sensitive. Adjusting the value of R2021 slightly lower would raise the output of the 10P and may provide a viable solution as well.
You are at my favorite stage of speaker design; The final voicing.
Enjoy trying combinations of subtle changes to make the design your own.
C
Only if it is insufficiently teased. Once done, it is one of th emost stable kinds of fill. It is difficualt, and takes some time to properkly tease. With the amount in Halcyon, i would expect, you and the SO woul dtake an entire movie to properly tease it.
dave
dave
OK, Lawrence of Arabia should do, or maybe Gone with the Wind. I’ll try that first. Thanks everybody. I’ll keep you informed of any progress.
Curt, when you say adjust R2021 slightly, I don’t know what slightly means. 10%? 2%?. I just don’t have a feel for these things. Thanks.
Curt, when you say adjust R2021 slightly, I don’t know what slightly means. 10%? 2%?. I just don’t have a feel for these things. Thanks.
It's hard for me to specify exactly, since I do not know if the woofers are more sensitive, or if they are, by how much. The current value of R2021 is 8.2 ohms. Unfortunately there is a large jump between the next lower value of 6.8 ohms. I would suggest purchasing a 1 ohm, resistor, a 6.2 ohm resistor, and a 6.8 ohm resistor for each speaker. Combinations of these resistors would provide values between 6.2 and 7.8 ohms. This may not fix boom per se, but will match the drivers sensitivities (if necessary) which could be interpreted as boom. I would highly recommend wire-wounds, as in my experience, the 10P did not like MOX resistors at all.
I'd go the stuffing route first, though and see how that fares. Sounds like you are close...
While, we are talking long old movies, I'll suggest Doctor Zhivago as a 3 hr 20 min long drama to tease by...
Alan,
That's a state of the art amplifier you got there.
Btw, are your speakers very close to the wall? Sometimes bringing them forward (away from the wall) by a few inches helps. The Halcyon's being quite deep cabinets makes that a bit difficult though.
That's a state of the art amplifier you got there.
Btw, are your speakers very close to the wall? Sometimes bringing them forward (away from the wall) by a few inches helps. The Halcyon's being quite deep cabinets makes that a bit difficult though.
Excellent thought, Zman. I went through a similar thought process. Certainly the room interaction could have a significant effect on the bass. Not only proximity to adjacent walls, but also the room size could support the frequencies in question with standing waves, which could exacerbate the issue.
Burnt resistor candle? OMG! Too funny! Of course those of us in the DIY community do not need to resort to such artifice. -We can generate it for real.
"We don't need no stinking candles!"
-I guess I'm still stuck on the movie theme...
C
Burnt resistor candle? OMG! Too funny! Of course those of us in the DIY community do not need to resort to such artifice. -We can generate it for real.
"We don't need no stinking candles!"
-I guess I'm still stuck on the movie theme...
C
UMM6 calibrated mic or the mini DSP UMIK (both very comparable to one another) with REW would give some insight into the room. Also some dimensions would help to predict room mode frequencies as well.
I know the Halcyons have a series crossover so what I'm about to suggest may not work the same way. I tune my bass damping and sensitivity with parallel resistors, yes a resistor in parallel with the woofer. Some people may consider that anathema. I am using an 8 ohm woofer so I have scope to keep the overall Z above 4 ohms. I currently have 26 ohms in parallel. Its basically cheaper than changing large inductors. This only works with passive xovers as the inductor forms a potential divider. It also has the effect of making the speaker look more resistive from the amplifiers point of view although the overall impedance is also reduced.