For large and heavy speakers I use a motorcycle lift. But it only reaches a height of 3 feet.
Maybe you could combine several lifts.
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ErinsAudioCorner
- Thread starter hardisj
- Start date
For large and heavy speakers I use a motorcycle lift. But it only reaches a height of 3 feet.
Maybe you could combine several lifts.
tuga
Major Contributor
Won't the tray produce unwanted reflections?
OP
- Thread Starter
- #123
I was thinking of this last night but hanging the speaker. Didn't consider using it as a platform. That said, do you think it would be sturdy enough to place a floorstander on top of?
Something else I looked at was this:
https://www.harborfreight.com/high-position-motorcycle-lift-99887.html
I like this option because I could set the speaker/turntable/platform on top of this tray and use it to help me raise it an additional 2.5 feet which, if nothing else, makes things a bit more safe since I could load it from the ground and then raise it to measurement height.
Same goes for something like this:
https://amzn.to/3br2OQp
OP
- Thread Starter
- #124
And that's the crux of one of the issues. So the tray would be one platform. The second (top) tier would be the speaker support. Audioholics does this.
https://www.audioholics.com/bookshelf-speaker-reviews/mp-65rt/MPRibbonoutdoortesting.jpg/image
OP
- Thread Starter
- #125
Ha! You beat me to the punch. I just posted something similar above.
Are you satisfied with this? I was thinking of using this as my first tier; setting the turntable and speaker platform on top of and using the lift to make life a little bit easier.
OP
- Thread Starter
- #126
I even look at drywall hangers last night. What I like is they can extend up to 11.5 feet (would never go that high) and they spin. So I could buy one, modify it with a platform adapter and mark it for polar response measurements. This thing looks practically perfect. But... I don't know how stable it is. Some videos I watched make it look kind of wobbly. With a speaker at the center it might be OK. This may be one of those "buy and try" things.
https://www.harborfreight.com/drywa...XN6YGWhXBpe-pPH8yDDyh46qSusKFJo4aAjHtEALw_wcB
You can see what I mean about it being wobbly in this video. But I'm wondering if placing a platform on it and simply weighing it down with a sandbag or cinder block behind the speaker would help stabilize it.
https://www.harborfreight.com/drywa...XN6YGWhXBpe-pPH8yDDyh46qSusKFJo4aAjHtEALw_wcB
You can see what I mean about it being wobbly in this video. But I'm wondering if placing a platform on it and simply weighing it down with a sandbag or cinder block behind the speaker would help stabilize it.
Perhaps the electrical impulses of our neurons are quantum entangled.Ha! You beat me to the punch. I just posted something similar above.
It is certainly not perfect and next time I would take the version without wheels, but so far I am satisfied.
I have to extend my turntable a little bit to the back so that the sound source is exactly above the rotation axis.
The shown bass compartment has the dimensions width x height x depth with 45x75x55cm and is relatively fixed. When the lift is extended, I use a belt to fix the speaker.
OP
- Thread Starter
- #128
Ok. I like this method. Mine would be a little different but the same premise. Wish I could source a lift locally (I checked used outlets as well) to go ahead and try today.
OP
- Thread Starter
- #129
I have spent the last day testing the Elac DBR62 in various fashions. If you saw my earlier post/link to the DBR62 thread review you'll know what I'm talking about. The basis was to compare to Amir's results. I measured in the following manner:
Test # 1) Speaker on platform ~ 8.5 feet off the ground; window to about 13ms with accuracy down to approximately 100hz.
Speaker flush with front of platform (picture was taken before I began tests).
Pros: This method has the benefit of having very high resolution as you go above 200hz.
Cons: being subject to the elements (cold, wind, rain; external noise not really an issue in my area) and having to hoist a speaker up 8.5 feet in the air and risk throwing out my shoulder should I ever test a floorstanding speaker.
Here's a photo of the setup (I am using thumbnails on purpose; don't want to swamp this page with oversized images).
Here's the result compared to Amir's. You can see some decent differences namely above 1khz. Notably the 1-2khz region.
Now, I wouldn't say that test was 'final'; it was just a "proof of concept" and I suspect that I could probably get better accuracy with an additional test and higher # samples that feed the average. Given the hassle of setting the speaker up high I thought I would try a few other methods out to see how they compare.
Ok. That brings you up to speed to today's testing. Where I tried a number of things. I'll list the method, the pros/cons and provide a picture of the setup as well as my result vs Amir's result. Note: The stand was thrown together from scrap wood; if I were to use this it would change. But I didn't want to waste too much time because storms are setting in this afternoon and I needed to get to work. Also, ignore levels for now. I used a mic calibration file for FR but haven't checked the level with the pistonphone; I only care about the general trends for this process.
Test # 2) Measurement on a 5 foot stand in my garage; gating was about 4 ms.
Same stand used below but inside my garage with a ceiling height of about 10 feet. The speaker was positioned about 5 feet above the ground with the tweeter at about 10" off the platform.
Pros: Don't have to worry about the elements nor do I have to hoist the speaker 8 feet in the air.
Cons: Poor resolution below 1khz. I don't think I would even bother posting this data. For a single drive unit it's fine. But, speaking from experience, I need good resolution to determine where to merge LF response data of ported loudspeakers.
I didn't take a picture of this setup.
Here's the result compared to Amir's:
Test # 3) Outdoors on stand. Same stand as before. Window ~ 7ms.
Pro: Better resolution than garage measurement since ceiling reflection isn't there and thus gating is extended an additional 3ms or so.
Con: Outoors; weather/environment. Still not as good as the 8.5 foot platform or ground plane measurement (see below).
Here's the result compared to Amir's:
Test # 4) Ground Plane Measurement: Speaker Angled ~ 8 degrees; window out to 40ms before first reflection.
Speaker was angled at about 8 degrees so that the tweeter would be pointing on-axis with the microphone (well, as on-axis as it can be without burying the mic and pointing the mic at the DUT). Note that while the response was gated here, if I were to actually use this method I would move to the back yard where I could get the nearest reflection about 40 feet away which should get me down to around 20hz. So, this was more a sanity check test.
Pro: Invulnerability to reflection; I can get ever further out in my backyard. High resolution in to the very low frequency region.
Con: Outdoors. Diffraction effect of speaker changes due to the baffle doubling (via the mirror image effect). HF > 10khz seems to be a pain. From my research that's generally accepted as questionable. Though, I had decent results.
Phone placed at tweeter on baffle and used in 'selfie' mode to make sure the microphone was at the center of the image (trick I learned on another website).
Here's the result compared to Amir's:
Conclusion:
At face value, each of my methods look pretty reasonable. And all are pretty much "industry standard". You can go to a website or magazine and see any number of reviewers using any of the above methods. But I wanted to do a comparison myself and see if there was any one method that is better than the other. Unfortunately, there isn't. I was hopeful the Ground-Plane method would yield the utmost accuracy (aka: match what Amir has). But it's missing the 600 hz - 1khz bump Amir's data shows and there's a slight difference in the LF region. Potentially diffraction effects; but playing around in EDGE and VirtuixCAD I didn't see the influence. Otherwise, it looks pretty dang good.
There's two possible reasons I'm seeing differences: 1) none of the methods I use are fool-proof or 2) I shouldn't put all my trust in to the NFS (not saying it's wrong; just saying it may also have a few things that make 97% accurate instead of 100% accurate; keeping in mind that an anechoic chamber has its own issues). I think the answer may actually be a large heaping of #1 and a small portion of #2. All of that said, once you combine these possibilities with the level of detail I'm viewing this in... really, none of my results are extremely different from the NFS results. They're just different in some areas and alike in others. I mean, I'm usually within 2dB difference. Which, yea, it's not minimal but in the grand scheme of things, I'd say that's not too bad. I want to be closer, though.
Ultimately, this is where I am at:
I still want to re-test on the 8.5 foot platform. Maybe I can do that tomorrow.
Measuring in the garage is convenient. Measuring outdoors provides better resolution, especially in the area where I would need to perform low-frequency response stitching and that is useful in determining how best to align the two sets of measurements.
I would prefer to find a method that yields the best accuracy without the need for additional post-processing. Though, when I started this venture my plan was to use the outdoor farfield measurement for > 200hz response and merge that with a ground-plane measurement for low frequency.
But if I could figure out how to calculate the diffraction impact then I could just remove it from the result. I could also use the near-field technique but if I were to get an oddly shaped port (flared) or something that's harder to easily measure and quantify then that would impact accuracy as well. There's also the "mic in the box" method but it has the issue of being able to fit a mic; some speakers (like this Elac) won't allow my mic inside the slot port.
If you've read this far I assume you have some vested interest in these results. So, I welcome your opinions, as either or both fellow testers and reviewers.
Test # 1) Speaker on platform ~ 8.5 feet off the ground; window to about 13ms with accuracy down to approximately 100hz.
Speaker flush with front of platform (picture was taken before I began tests).
Pros: This method has the benefit of having very high resolution as you go above 200hz.
Cons: being subject to the elements (cold, wind, rain; external noise not really an issue in my area) and having to hoist a speaker up 8.5 feet in the air and risk throwing out my shoulder should I ever test a floorstanding speaker.
Here's a photo of the setup (I am using thumbnails on purpose; don't want to swamp this page with oversized images).
Here's the result compared to Amir's. You can see some decent differences namely above 1khz. Notably the 1-2khz region.
Now, I wouldn't say that test was 'final'; it was just a "proof of concept" and I suspect that I could probably get better accuracy with an additional test and higher # samples that feed the average. Given the hassle of setting the speaker up high I thought I would try a few other methods out to see how they compare.
Ok. That brings you up to speed to today's testing. Where I tried a number of things. I'll list the method, the pros/cons and provide a picture of the setup as well as my result vs Amir's result. Note: The stand was thrown together from scrap wood; if I were to use this it would change. But I didn't want to waste too much time because storms are setting in this afternoon and I needed to get to work. Also, ignore levels for now. I used a mic calibration file for FR but haven't checked the level with the pistonphone; I only care about the general trends for this process.
Test # 2) Measurement on a 5 foot stand in my garage; gating was about 4 ms.
Same stand used below but inside my garage with a ceiling height of about 10 feet. The speaker was positioned about 5 feet above the ground with the tweeter at about 10" off the platform.
Pros: Don't have to worry about the elements nor do I have to hoist the speaker 8 feet in the air.
Cons: Poor resolution below 1khz. I don't think I would even bother posting this data. For a single drive unit it's fine. But, speaking from experience, I need good resolution to determine where to merge LF response data of ported loudspeakers.
I didn't take a picture of this setup.
Here's the result compared to Amir's:
Test # 3) Outdoors on stand. Same stand as before. Window ~ 7ms.
Pro: Better resolution than garage measurement since ceiling reflection isn't there and thus gating is extended an additional 3ms or so.
Con: Outoors; weather/environment. Still not as good as the 8.5 foot platform or ground plane measurement (see below).
Here's the result compared to Amir's:
Test # 4) Ground Plane Measurement: Speaker Angled ~ 8 degrees; window out to 40ms before first reflection.
Speaker was angled at about 8 degrees so that the tweeter would be pointing on-axis with the microphone (well, as on-axis as it can be without burying the mic and pointing the mic at the DUT). Note that while the response was gated here, if I were to actually use this method I would move to the back yard where I could get the nearest reflection about 40 feet away which should get me down to around 20hz. So, this was more a sanity check test.
Pro: Invulnerability to reflection; I can get ever further out in my backyard. High resolution in to the very low frequency region.
Con: Outdoors. Diffraction effect of speaker changes due to the baffle doubling (via the mirror image effect). HF > 10khz seems to be a pain. From my research that's generally accepted as questionable. Though, I had decent results.
Phone placed at tweeter on baffle and used in 'selfie' mode to make sure the microphone was at the center of the image (trick I learned on another website).
Here's the result compared to Amir's:
Conclusion:
At face value, each of my methods look pretty reasonable. And all are pretty much "industry standard". You can go to a website or magazine and see any number of reviewers using any of the above methods. But I wanted to do a comparison myself and see if there was any one method that is better than the other. Unfortunately, there isn't. I was hopeful the Ground-Plane method would yield the utmost accuracy (aka: match what Amir has). But it's missing the 600 hz - 1khz bump Amir's data shows and there's a slight difference in the LF region. Potentially diffraction effects; but playing around in EDGE and VirtuixCAD I didn't see the influence. Otherwise, it looks pretty dang good.
There's two possible reasons I'm seeing differences: 1) none of the methods I use are fool-proof or 2) I shouldn't put all my trust in to the NFS (not saying it's wrong; just saying it may also have a few things that make 97% accurate instead of 100% accurate; keeping in mind that an anechoic chamber has its own issues). I think the answer may actually be a large heaping of #1 and a small portion of #2. All of that said, once you combine these possibilities with the level of detail I'm viewing this in... really, none of my results are extremely different from the NFS results. They're just different in some areas and alike in others. I mean, I'm usually within 2dB difference. Which, yea, it's not minimal but in the grand scheme of things, I'd say that's not too bad. I want to be closer, though.
Ultimately, this is where I am at:
I still want to re-test on the 8.5 foot platform. Maybe I can do that tomorrow.
Measuring in the garage is convenient. Measuring outdoors provides better resolution, especially in the area where I would need to perform low-frequency response stitching and that is useful in determining how best to align the two sets of measurements.
I would prefer to find a method that yields the best accuracy without the need for additional post-processing. Though, when I started this venture my plan was to use the outdoor farfield measurement for > 200hz response and merge that with a ground-plane measurement for low frequency.
But if I could figure out how to calculate the diffraction impact then I could just remove it from the result. I could also use the near-field technique but if I were to get an oddly shaped port (flared) or something that's harder to easily measure and quantify then that would impact accuracy as well. There's also the "mic in the box" method but it has the issue of being able to fit a mic; some speakers (like this Elac) won't allow my mic inside the slot port.
If you've read this far I assume you have some vested interest in these results. So, I welcome your opinions, as either or both fellow testers and reviewers.
Last edited:
This one is very close! I would have called it done at this point.Here's the result compared to Amir's:
Thanks for all the experiments.
Your thread motivated me to search for a lift for my use. I need to elevate the speaker to about 56 inches and then slide it on a platform. With my wife and I, we had a hell of a time getting a Revel F35 on the stand. It is challenging because the Klippel NFS fixture has legs that come out so you have to be careful to not trip over them.
So I needed something that would lift at least 56 inches. That ruled out many of the fixtures shown here (and I could not trust that TV lift with a speaker cantilevering from it). This is what I bought that should be here on Friday I think: https://smile.amazon.com/gp/product/B0054M082Y/ref=ppx_yo_dt_b_asin_title_o01_s00?ie=UTF8&psc=1
What is cool is that it is light because it is made out of aluminum. Doesn't take a lot of space. And, it acts as a dolly so you can carry things around with it. It lifts to 58 inches it says so close.
So I needed something that would lift at least 56 inches. That ruled out many of the fixtures shown here (and I could not trust that TV lift with a speaker cantilevering from it). This is what I bought that should be here on Friday I think: https://smile.amazon.com/gp/product/B0054M082Y/ref=ppx_yo_dt_b_asin_title_o01_s00?ie=UTF8&psc=1
What is cool is that it is light because it is made out of aluminum. Doesn't take a lot of space. And, it acts as a dolly so you can carry things around with it. It lifts to 58 inches it says so close.
OP
- Thread Starter
- #132
Your thread motivated me to search for a lift for my use. I need to elevate the speaker to about 56 inches and then slide it on a platform. With my wife and I, we had a hell of a time getting a Revel F35 on the stand. It is challenging because the Klippel NFS fixture has legs that come out so you have to be careful to not trip over them.
So I needed something that would lift at least 56 inches. That ruled out many of the fixtures shown here (and I could not trust that TV lift with a speaker cantilevering from it). This is what I bought that should be here on Friday I think: https://smile.amazon.com/gp/product/B0054M082Y/ref=ppx_yo_dt_b_asin_title_o01_s00?ie=UTF8&psc=1
What is cool is that it is light because it is made out of aluminum. Doesn't take a lot of space. And, it acts as a dolly so you can carry things around with it. It lifts to 58 inches it says so close.
Glad to hear I was in some way able to help.
I looked at a lift like that myself for the same reasons you mentioned. But they were just too $$$. If I decide to go with the "speaker in the sky" method then I'll continue with my stand but may revisit this item if things pick up enough for me to spend the cash. But I secretly hope you test all the heavy ones before I have a chance to so I won't feel the desire to bother. LOL
dc655321
Major Contributor
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Could you create an offset? If you eventually get more of the same speakers measured (even though not the exact same models measured by Amir ), you can see if any universal differences exist.
OP
- Thread Starter
- #135
If I understand your question (sorry, my brain hurts after all this stuff today) you're just wanting to know if the reflection that is limiting the LF-extension in my measurement bad enough to worry with?
If so, note that while the response was gated here, if I were to actually use this method I would move to the back yard where I could get the nearest reflection about 40 feet away which should get me down to around 20hz. So, this was more a sanity check test. I'll edit my post.
But, here's the screenshot from my Klippel measurement (I just dumped the data in to REW for comparison to Amir's)
OP
- Thread Starter
- #136
Culminating enough data to see a trend; sure. I do have the Adam S2V on hand that Amir tested that I plan to test out as well. That said, in the ideal world I could take one or two of the methods I used and get results that equal Amir's. It bothers me that in some cases there are differences in different areas. I think the ground plane measurement might be the best bet for a 'full range' test but with the unknowns, I currently feel best using the really tall platform.
I plan to kick an email out to Klippel to ask my contacts there what they think. But I want to test on the 8.5 foot platform again; hopefully tomorrow.
dc655321
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Yes, that's exactly what I would like to know.
Would be interesting to see the ungated frequency response from the ground-plane measurement versus the gated response (both plotted in REW, along with @amirm's NFS measurement).
Given the small amplitude of the reflected signal in the impulse response, one may have to squint rather hard to see effects...
OP
- Thread Starter
- #138
See below. This is all smoothed to 1/24 Octave.
It creates a lot of ripples (error). I wouldn't use this. *IF* I were to use the GP method I'd move it to the backyard which is a bit further away from any surface. Or just chop it at the first reflection and let it ride.
Can you spread the y-axis of the impulse response further so that we can see if there are still slight reflections before the gate?
The GP measurement actually looks good. It could be that the transition to the lawn is causing reflections. This should also be visible in the impulse response, if scaled correctly.
OP
- Thread Starter
- #140
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