Wow, thanks for those clips. Sans the room tone it sounds very much like a reference. I didn't notice any box coloration listening here (in a treated room on mastering grade monitors).
Do you think excitation of the front baffle in the 200-300hz zone plays any role in the THD rising down there? Can you feel any cabinet vibration on midbass? Or was that just an effect of measuring in the untreated room.
If you boost the 12khz to 20khz range with 3-5db of EQ do you find it adds some nice air/presence or does that go to far and sound unnatural? I'm curious how FR these vifa's truly are.
The only reason I can imagine people wouldn't build these is because they are boring -> as in, Nautaloss does so many things right, aside from efficiency and directivity, what's left to tinker with, whats the next step? This has been my reaction to them, hesitation that the party might be over due to a 9 dollar driver and some foam core. Thankfully directivity and spl are still concerns and probably mutually exclusive in some ways, unless this worked as a line array back chamber...
Do you think excitation of the front baffle in the 200-300hz zone plays any role in the THD rising down there? Can you feel any cabinet vibration on midbass? Or was that just an effect of measuring in the untreated room.
If you boost the 12khz to 20khz range with 3-5db of EQ do you find it adds some nice air/presence or does that go to far and sound unnatural? I'm curious how FR these vifa's truly are.
The only reason I can imagine people wouldn't build these is because they are boring -> as in, Nautaloss does so many things right, aside from efficiency and directivity, what's left to tinker with, whats the next step? This has been my reaction to them, hesitation that the party might be over due to a 9 dollar driver and some foam core. Thankfully directivity and spl are still concerns and probably mutually exclusive in some ways, unless this worked as a line array back chamber...
Anthonybisset,
Glad you think it sounds "monitor" like in quality.
I recorded a pink noise clip (no sub woofer) with the Zoom H4 which should have response into the high range. Do me a favor and analyze this clip to see what the HF response is - there is no room treatment with foam and stuff here as I was interested in the high range. Also, this is the second monitor.
I don't have an EQ so cannot do what you suggest unless I source it with my laptop and use a player program.
There is definitely some cabinet vibrations I can feel on the foam core. I wonder if that is causing the bread loaf hump in the THD at 3.3 kHz too. Driver THD tends to be smooth sailing once it clears initial bass uneveness so it would not surprise me.
Glad you think it sounds "monitor" like in quality.
I recorded a pink noise clip (no sub woofer) with the Zoom H4 which should have response into the high range. Do me a favor and analyze this clip to see what the HF response is - there is no room treatment with foam and stuff here as I was interested in the high range. Also, this is the second monitor.
I don't have an EQ so cannot do what you suggest unless I source it with my laptop and use a player program.
There is definitely some cabinet vibrations I can feel on the foam core. I wonder if that is causing the bread loaf hump in the THD at 3.3 kHz too. Driver THD tends to be smooth sailing once it clears initial bass uneveness so it would not surprise me.
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Quick pinknoise mono rms snapshop... (Untreated room. Zoom H4 (not to beat up on it, but bleh).
For reference, perfect reproduction of white/pink/brown noise sources should look something like the images here:
http://www.cim.mcgill.ca/~clark/nordmodularbook/nm_noise.html
I think room reflections are strongly impacting the FR (as would be expected).
For reference, perfect reproduction of white/pink/brown noise sources should look something like the images here:
http://www.cim.mcgill.ca/~clark/nordmodularbook/nm_noise.html
I think room reflections are strongly impacting the FR (as would be expected).
fwiw, Zoom h4 recordings are a bit of a nightmare to work on in post... FR is not flat and phase is mucked up a bit.
h4 mk2 is probably sig better... I haven't had the (dis)pleasure of trying to work with anything off a zoom since the h4 model. cured of me of my interest in that company.
but I should clarify, the zoom is probably the smallest player in that uneven response.
h4 mk2 is probably sig better... I haven't had the (dis)pleasure of trying to work with anything off a zoom since the h4 model. cured of me of my interest in that company.
but I should clarify, the zoom is probably the smallest player in that uneven response.
So it looks like the Vifa does have at least response out to 16khz? I need a good ADC for measurements. Ideally, I should make measurements outdoors? I had the Zoom about 4 in away from the driver face, that may be mucking things up because the unit is big and is probably causing reflections and cancellations in the HF. My WM61a mic is mounted on the end of a slender 0.5 in dia x 12 in long aluminum tube.
Hi xrk971
Yes, the fantastic cornus! I built a pair out of small pizza boxes, they sound splendid when hanged on the wall but I haven’t done any measurements on them yet (I am drown into other projects).
The shell speakers were carried away by my younger daughter. She used them with her tablet. Tinny units and beautiful, no measurements for them either. I don’t know if she still has them.
Keep on the good work
George
George,
Nice work with the pizza box Cornu! You should have posted this in the Cornu thread - I will post link to this in that thread. What drivers did you use in them?
Reagrds,
X
Have to agree 4inches seems way too close for hf measurement.
So yeah, it looks like the vifa extends out past 14k and is down maybe 10dB (from the probable average) at 16k. That's pretty good (was your pink noise capture recorded directly to mp3 in the zoom?, mp3 format has a brickwall filter at 16k).
IMO/e for reference monitoring/mix evaluation we would need reasonable signal up to 17-17.5k. For instance the Urei 809/811/813's and altec co-axials i've used have rolled off above 15khz and plenty of good music was mixed on those (so extension isn't all it's made out to be)... A friend related that one famous mix engineer he worked with had a principle of not touching anything above 12khz no matter what cut/boosts he was making in the material below, he just left > 12khz alone... This is my rational for why the vifa might actually be reference quality... I'd rather have to 17k without a second driver, crossover and spatial/temporal alignment needing to be involved.
Curious to see how an outdoors measurement at 1m and 3m turns out.
/a
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I had a setting in the Zoom H4 set to emulate a U87 mic and I turned that off to get a neutral response. A recording of of some jazz with a drum kit in 96khz 32 bit wav when analyzed on Audacity indicated that there is content all the way to 18kHz with the Vifa's. Here is the spectrum:
And attached is an mp3 compressed representation of that raw .wav file. I think it sounds pretty airy now - as the type of music that has highs is required if you want to hear high.
And attached is an mp3 compressed representation of that raw .wav file. I think it sounds pretty airy now - as the type of music that has highs is required if you want to hear high.
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Hey, all I can do is put stuff out there and if folks don't think having at least one set of speakers to give them the 'truth' from time to time isn't cool or exciting, then I don't know what to say. Note that this enclosure will also work with 'expensive' full range drivers too if one is too embarrassed to admit that a $10 driver can be this good.
Update on more listening impressions: what I am coming to the realization is that the Nautaloss works with all my different genres of music equally well. Clearly, jazz sounds great, as does girl and guitar stuff, but I was really surprised how well classic rock, blues, pop, hip hop, classical, and even metal all sounds very good. Many of my other speakers would excel in one genre or another. Clearly, one cannot get high SPL from a single full range driver, but at moderate to fairly loud (defined by swmbo saying to me turn it down because she can hear it from upstairs), it works very well. I believe this all-around capability comes from having an accurate and flat response and the ability to produce clean and fast transients. Large complex orchestral pieces of course, can overwhelm this driver at louder levels, but at moderate levels it sounds very good. I did an A/B test by comparing the speakers to what I heard on my studio monitor headphones by putting them on and taking them off with the speakers playing. The sound was very close - with exception of lacking some of the sparkle that the headphones have above 17 khz.
Nautaloss plan for 3 inch to 4 inch class driver
Here is the plan as drawn on the foam core prior to gluing. The main sheet dimensions are 12 in tall x 9 in wide. Although I used a Vifa TC9FD, this can be used for most 3 to 4 in class drivers as the function is to absorb the back wave, the enclosure does not have to be specifically tuned for driver parameters. However, for sufficient bass extension, if that is what you are shooting for with a higher Qts driver, make sure you have enough volume.
The width of the cabinet is 5 in (internal) and I am sure there is leeway there too for adjustment for visual appeal/volume adjustment.
Here is the plan as drawn on the foam core prior to gluing. The main sheet dimensions are 12 in tall x 9 in wide. Although I used a Vifa TC9FD, this can be used for most 3 to 4 in class drivers as the function is to absorb the back wave, the enclosure does not have to be specifically tuned for driver parameters. However, for sufficient bass extension, if that is what you are shooting for with a higher Qts driver, make sure you have enough volume.
The width of the cabinet is 5 in (internal) and I am sure there is leeway there too for adjustment for visual appeal/volume adjustment.
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More efficient dual Vifa option
For those of you looking for a 91 dB sensitivity at 2.83V (4 ohms) and wanting higher SPL, use a 2nd order high pass filter at 300 Hz, stack dual drivers one on top of the other and *reduce* the spiral pathlength by 7 inches and here is what you can get - about 105dB max SPL.
SPL at xmax of 2.5mm with 30 volts rms:
For those of you looking for a 91 dB sensitivity at 2.83V (4 ohms) and wanting higher SPL, use a 2nd order high pass filter at 300 Hz, stack dual drivers one on top of the other and *reduce* the spiral pathlength by 7 inches and here is what you can get - about 105dB max SPL.
SPL at xmax of 2.5mm with 30 volts rms:
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I was thinking the same thing - one can make 12 of these and stack them sideways to form a 24 driver array (substitute an 8 ohm resistor for the missing driver to keep it nominal 8 ohm impedance in parallel series wiring). It may actually help clean up the rear wave issue that you are trying to manage with an oval shaped chamber with irregular wall shapes. Also, 12 modular Nautaloss units will be very light and easy to move/setup.
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Measurements of Unit 2
Here are some measurements of the second unit. Room placement was not exactly the same as the first measurement so there are some differences in the region below 300 Hz. There appears to be a mild rise in the frequency response - not sure what is causing this but could just be baffle step loss or the fact that this driver did not get benefit of a 24 hr break-in playing into a sealed box like the first unit. Shown are measurements at 0 deg (blue), 30 deg (red), and 45 deg (green) off axis, all at 12 in away. The THD hump near 3kHz goes away at 45 deg off axis which seems to indicated that this is a cone-breakup induced distortion? Still not to bad for THD, but a little higher than unit 1 by 5 to 10 dB. Again, this is with the laptop sound card that has no response above 6kHz.
Here are some measurements of the second unit. Room placement was not exactly the same as the first measurement so there are some differences in the region below 300 Hz. There appears to be a mild rise in the frequency response - not sure what is causing this but could just be baffle step loss or the fact that this driver did not get benefit of a 24 hr break-in playing into a sealed box like the first unit. Shown are measurements at 0 deg (blue), 30 deg (red), and 45 deg (green) off axis, all at 12 in away. The THD hump near 3kHz goes away at 45 deg off axis which seems to indicated that this is a cone-breakup induced distortion? Still not to bad for THD, but a little higher than unit 1 by 5 to 10 dB. Again, this is with the laptop sound card that has no response above 6kHz.
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New Measurements w/ UMM-6 Mic
I finally got a real microphone (Dayton UMM-6 USB mic) that captures the HF. Here are the measurements for both speakers at 12 in away and 0 deg. The response truly extends into 20 kHz.
I think that this is a pretty flat response over the range of 100 Hz to 20 kHz.
I finally got a real microphone (Dayton UMM-6 USB mic) that captures the HF. Here are the measurements for both speakers at 12 in away and 0 deg. The response truly extends into 20 kHz.
I think that this is a pretty flat response over the range of 100 Hz to 20 kHz.
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I finally got a real microphone (Dayton UMM-6 USB mic) that captures the HF. Here are the measurements for both speakers at 12 in away and 0 deg. The response truly extends into 20 kHz.
I think that this is a pretty flat response over the range of 100 Hz to 20 kHz.
can you do some gated CSD's?