Hi satx,
The only way to be sure of the box tuning is to make an impedance measurement. My Box tuning has changed of ~5 Hz after two weeks of usage.
From WinISD simulations, with 40l cab, port 2.5", len is 3.9"
The only way to be sure of the box tuning is to make an impedance measurement. My Box tuning has changed of ~5 Hz after two weeks of usage.
From WinISD simulations, with 40l cab, port 2.5", len is 3.9"
WinISD does not take stuffing into account, I think that is why for example Troels multiplies the given port length with 0.7. My sheets give also the 3.9" length if not multiplied with the 0.7 factor. Stuffing in cabinets will increase the volume "seen by the drivers" as it slows down speed of the sound waves. (And again, take my comments with grain of salt as I am not very experienced in the science behind all of this).
😕
What i've seen is that WinISD simulation are correct in comparison with my impedance measurements.
Again, the only way to check the box tuning is to make an impedance measurement.
But I agree with you :
"If the bass output is too dominant and heavy, lowering the tuning will help in most of the cases."
Troels describes the effect of damping material here: Port Calculation scroll down to "The impact of damping materials in cabinet volume".
That is what I was intedend to tell. English, not being my native language, can sometimes do tricks to my intended messages 🙂 All in all, if you add more stuffing (loose material like sonofil or MDM3), the effective volume of the cabinet will be slightly bigger.
And I totally agree on your point; cabinet tuning can be determined by impedance plot.
That is what I was intedend to tell. English, not being my native language, can sometimes do tricks to my intended messages 🙂 All in all, if you add more stuffing (loose material like sonofil or MDM3), the effective volume of the cabinet will be slightly bigger.
And I totally agree on your point; cabinet tuning can be determined by impedance plot.
jlaakso, thanks a lot. I'm not to concerned with having the exact tuning, but I didn't want to be way off. I am doning it by ear and now that I know what length 40 should be I should be able to tweak it from there
Jon Krute talks about this in his design mantra under enclosure I believe. He says that his ports are always shorter than what is called for by programs like WinISD
Well Satx, it take 5$ to make a jig for impedance measurement and an hour to understand how to use REW for that 🙂
What about the tweeter level of your speakers ?
If you have an equalizer with your music player, could you test -2 dB in the 12k, 14k bands ?
What about the tweeter level of your speakers ?
If you have an equalizer with your music player, could you test -2 dB in the 12k, 14k bands ?
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Pascal,
I am going to make the jig when I get the time to get the parts. The tweeter level seems nice to me; I tried leaving the 18R out and didn't like it at all, but may try again later. I don't know what resisters to adjust to adjust level or how much to adjust them. I don't have an equalizer. Just use a Peachtree Nova and an Apple TV for lossless and a cdp. I do run the Peachtree in Ht bypass when not using it for music and my receiver has an adjustable equalizer. Are you saying to use the equalizer just to see if I would want to adjust tweeter?
I am going to make the jig when I get the time to get the parts. The tweeter level seems nice to me; I tried leaving the 18R out and didn't like it at all, but may try again later. I don't know what resisters to adjust to adjust level or how much to adjust them. I don't have an equalizer. Just use a Peachtree Nova and an Apple TV for lossless and a cdp. I do run the Peachtree in Ht bypass when not using it for music and my receiver has an adjustable equalizer. Are you saying to use the equalizer just to see if I would want to adjust tweeter?
Hi satx,
1 - I think the tweeter level is two high, it sounds much better with 1051 : 1.2 Ohms and 1061 : 15 ohms providing a 0.5 more dB of attenuation.
2 - With this values I think there still is too much energy in the 12 -14 KHz range, I found lowering this two bands of 2dB with an equalizer inprove the sound,
especially a high level.
3 - The contour filter L1011 + R1011 (0.1 mH // 3.3 Ohms may not be the best implementation to make the 810921 sound right.
Few people have used a notch filter like used in this design :
Usher 8945P 7" / Peerless HDS 1" MTM
An alternative maybe using a waveguide boosting the 3-8KHz range flatening the SPL curve.
1 - I think the tweeter level is two high, it sounds much better with 1051 : 1.2 Ohms and 1061 : 15 ohms providing a 0.5 more dB of attenuation.
2 - With this values I think there still is too much energy in the 12 -14 KHz range, I found lowering this two bands of 2dB with an equalizer inprove the sound,
especially a high level.
3 - The contour filter L1011 + R1011 (0.1 mH // 3.3 Ohms may not be the best implementation to make the 810921 sound right.
Few people have used a notch filter like used in this design :
Usher 8945P 7" / Peerless HDS 1" MTM
An alternative maybe using a waveguide boosting the 3-8KHz range flatening the SPL curve.
Hmm, I assumed you were trying to bump the tweeter level up not attenuate further. That sounds like something I might be interested in trying. I really don't like a bright, fatiguing, shouting speaker, that is one of the main things I was trying to accomplish with this build. I do like the balance as it is now, but I would be up for trying to improve upon it.
Are you saying that it was too bright even with R1061 of 18 ohms in place? Because with and R1061 of 15 ohms I would think it would provide less attenuation, but I'm really new to this.
Evan
Yes, that's it, I've always used R1061 in my filters.
With a value of R1061 15 Ohms you provide more attenuation than with 18 because this resistor is in // with the tweeter.
The combination of R1051 and R1061, wich is called L-pad, provide 2.5 dB of attenuation with the value 1.2 and 15 ohms vs 2.0 dB with 1.0 and 18 ohms values.
I will open a new thread concerning the tweeter filter.
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Ah, excellent explanation, thanks. I didn't know that in // changed the behavior of the resistor. So in series a higher value does create more attenuation?
So, what would you say are the benefits to the sound from this? Less bright? Does it reduce the midrange level slightly also. Overall smoother sound?
Evan
Evan
You can play with this calculator, for example or just have a look at the values at the end of the page :
:
L pad calculator - attenuation dB damping impedance decibel loudspeaker speaker voltage divider - sengpielaudio Sengpiel Berlin
It affects the whole range of the tweeter 3-20 Khz, about the sound it's difficult to explain because english int not my native language 🙂
smoother sound, yes. I can say for example that the female vocals are more naturals.
:
L pad calculator - attenuation dB damping impedance decibel loudspeaker speaker voltage divider - sengpielaudio Sengpiel Berlin
It affects the whole range of the tweeter 3-20 Khz, about the sound it's difficult to explain because english int not my native language 🙂
smoother sound, yes. I can say for example that the female vocals are more naturals.
Build tread question
Hi, I wanted to post a tread of my NOMEX build, should I post it here or start a new thread?
Evan
Hi, I wanted to post a tread of my NOMEX build, should I post it here or start a new thread?
Evan
Start a new one, that way your photos and comments will be contained in the first post, and you can edit it.