Removing the concrete gave you ~5dB increase in bottom end and what appears to be a more even response overall. That's good news!
Greg
New (Small Home Studio) Build, Norway
Originally posted at johnlsayers.com, topic 18593.
Thanks Dan for taking the time to comment. I will do as you described. There will be no problem to compresse the sorbathane enough with turnbuckles as they are very robust. So, this solves the sorbathane underneath the enclose. But what about inside the enclosure. There I also have sorbathane (underneath, on the sides and at the top). Will the same principle also apply here? 15-20% reduced? Here I can probably apply more sorbathane on top if I’m not able to compress the bottom ones enough. What about the sorbathane on the sides?As you can apply tension via the turnbuckles, you don't need to calculate. You just tighten until you get the correct deflection. Measure the height of the sorbathane prior to applying any tension/weight. Then tighten the turnbuckles until the height is 15-20% reduced. The weight of the speaker would only matter if you were resting the speakers on the sorbathane without any turnbuckles etc. If the sorbathane underneath the enclosure can't be compressed enough with the lighter speakers (unlikely to be the case), just remove an inner sorbathane pad to distribute more weight on the others. Dan
Thanks Greg for checking. That is better news! I will remove the other one as well. Also, I have talked to Presonus teck. He stated:Removing the concrete gave you ~5dB increase in bottom end and what appears to be a more even response overall. That's good news! Greg
So, this means I have some issues here as well. I’m wondering if I must change my speakers overall. Isn’t it normal to wall mount the amp from the speakers? I have seen studio projects on this site doing the same. Do they have special kind of speakers where the back amp is intended to be wall mounted? If so what kind am I looking for here? BjornThe modifications that you have made will indeed alter the audio. Each speaker is designed to interact with its individual acoustical environment. The way to restore your bass issues is to restore the amp paneling.
There are some brands of (active) speakers (I only know Genelec, but there are more as far as i know) that have a sealed speaker cabinet where the aluminium back plate with the amp is not the back of the cabinet itself. Therefore, disconnecting the aluminium back plate does not alter the cabinet volume and its acoustic behaviour. But those are quite expensive speakers compared to the Presonus Eris E5 you have. However, replacing the back of the speaker with a sealed aluminium back plate should work fine in general, but your speakers are so small, that the amount of electronics and the air that they supplant seems to have an impact on the bass reflex resonance frequency. And this resonance frequency defines the lowes frequency that the speaker is capable to reproduce.Also, I have talked to Presonus teck. He stated:So, this means I have some issues here as well. I’m wondering if I must change my speakers overall. Isn’t it normal to wall mount the amp from the speakers? I have seen studio projects on this site doing the same. Do they have special kind of speakers where the back amp is intended to be wall mounted? If so what kind am I looking for here? BjornThe modifications that you have made will indeed alter the audio. Each speaker is designed to interact with its individual acoustical environment. The way to restore your bass issues is to restore the amp paneling.
I understand. I think I will use this year to investigate different speakers. Until then I will use the once I have. Anyway, I have an extra speaker (same kind) that has not been taken out of the box. When I take out the cement block from the left speaker I will insert the untampered new speaker and run measurement again. I will use this measurement for reference to see the difference of one speaker with amp back plate (left side) and one (right side) with aluminum back plate. Thanks again for commenting. BjornThere are some brands of (active) speakers (I only know Genelec, but there are more as far as i know) that have a sealed speaker cabinet where the aluminium back plate with the amp is not the back of the cabinet itself. Therefore, disconnecting the aluminium back plate does not alter the cabinet volume and its acoustic behaviour. But those are quite expensive speakers compared to the Presonus Eris E5 you have. However, replacing the back of the speaker with a sealed aluminium back plate should work fine in general, but your speakers are so small, that the amount of electronics and the air that they supplant seems to have an impact on the bass reflex resonance frequency. And this resonance frequency defines the lowes frequency that the speaker is capable to reproduce.
Found posts from you and stuart explaining the "string trick" here. I will do the trick as explained to check viewtopic.php?f=1&t=21547&p=149845&hilit=string+trick#p149845 viewtopic.php?f=2&t=21368&p=148227&hilit=string+trick#p148227 -Bjorn-Also, you seem to have a strong reflection present in your right speaker and both speaker measurements. Here is the how far it is: Use the string trick to find out where this reflection is coming from. Greg
Ok, so did the string trick.
- measured the distance from the acoustic axis of myspeaker to the tip of my measurement mic
- added the distance I gave you to that measurement ( 150,51 cm )
As we can see on the photos it is most likely the back-left window. Could also be my guitars.
Anyway, in this case is there anything that can be done? I have heavy curtains in front but that’s probably not enough?
-Bjorn.
You did the string trick incorrectly. Ill try to explain it here but I'm the first to admit that I'm horrible at explaining things!
- tape the string to the speaker as you've done
- measure the distance from the speaker to your microphone (let's call that distance "A")
- let's call the distance my calculator split out "B" -- this is ~150.5cm
- add A and B. A+B = C
- C is the length your string has to be. Mark that length on the string.
- tape the string at the mark to the tip of your microphone. You will now have a saggy long string strung between your speaker and your microphone.
- gently grabbing the string in the middle where it's saggy, try to find a place in your room where that string touches.
Essentially, the string is showing us the path of the sound as it traveled from your speaker, bounced off of something, and then eventually hit your microphone. Typically the surfaces in question end up being the floor, the ceiling, the wall, the desk, etc. All things in the front half of the room, living somewhere between the speaker and the microphone.
I hope I explained it well enough to understand. Please let me know, and I look forward to seeing what is causing the issue.
Once you find a potential surface causing the issue, place a small piece of insulation on the surface and take another measurement. We SHOULD see the reflection disappear from the filtered IR on your REW data.
Also, thanks for providing pictures. It sure helps us see what is going on!
Greg
Yes, the 15-20% deflection is generally the optimum recommended by sorbathane for the best vibration damping.There I also have sorbathane (underneath, on the sides and at the top). Will the same principle also apply here? 15-20% reduced?
Most of the adjustments on the speakers will be "set and forget". So you don't need constant access to them. Most studios will just fit them unaltered in the soffits and leave the settings as they are. Then plug in an xlr cable in the back and cut the end off it and solder it on a wall plate xlr/combo socket. Then you just plug your output from your daw/mixer/desk into the wall plate. You can leave a removable panel on the side/front of your soffits, so you can reach in and adjust the settings if necessary. That's what I'm doing in my studio :) DanIsn’t it normal to wall mount the amp from the speakers? I have seen studio projects on this site doing the same. Do they have special kind of speakers where the back amp is intended to be wall mounted? If so what kind am I looking for here?
It is handy to wall mount the amp. Typically if there is a problem with a speaker, it is either the power amp or a driver (speaker). Having the amp accessible and the fact that most drivers can be removed from the front of the enclosure, this allows easy repair. In speaker modules like yours, it is difficult to remove the speaker to access the power amp. This also allows for easy tonal and volume adjustments. The only sensible way to adjust an active speaker with the amp module still mounted to the enclosure would be as Dan suggested which is to design your soffit such that there is an access panel.Isn’t it normal to wall mount the amp from the speakers?
For sure! For example, ATC Loudspeakers have kits for their speakers which allow you to remove the power amps. Also, many speaker manufacturers offer both active and passive versions of their speakers, passive allowing you to mount the power amp wherever you'd like. GregDo they have special kind of speakers where the back amp is intended to be wall mounted?
here you go ATC speakers with amps mounted below.
https://www.johnlsayers.com/Pages/Image ... O_%205.jpg
Cheers
john
If you have access to a 3d printer, you might be able to print a copy of the amp board, with the heatsink etc. and mount the print to the aluminium back plate, then it should displace the same amount of air volume in the speakers and have a very similar frequency response.
That could be a way to continue to have the amps wall mounted, with these speakers.
Dan
Thanks Greg. You explained perfectly. :D I will do it again as described above and post the result. 2 Time's The Charm :wink:You did the string trick incorrectly. Ill try to explain it here but I'm the first to admit that I'm horrible at explaining things! I hope I explained it well enough to understand. Please let me know, and I look forward to seeing what is causing the issue.
Will do!Once you find a potential surface causing the issue, place a small piece of insulation on the surface and take another measurement. We SHOULD see the reflection disappear from the filtered IR on your REW data.
Thanks. Pictures do say allot and I will try to keep them coming. -Bjorn-Also, thanks for providing pictures. It sure helps us see what is going on!
Thanks for the tip Greg. I will check them out.For sure! For example, ATC Loudspeakers have kits for their speakers which allow you to remove the power amps. Also, many speaker manufacturers offer both active and passive versions of their speakers, passive allowing you to mount the power amp wherever you'd like. Greg
Thanks John for commenting, means allot! :) I will add ATC to my new list of future monitor purchase. -Bjorn-here you go ATC speakers with amps mounted below. https://www.johnlsayers.com/Pages/Image ... O_%205.jpg Cheers john
Naice! I will do 15-20% on them all then.Yes, the 15-20% deflection is generally the optimum recommended by sorbathane for the best vibration damping.
That’s insane! but brilliant! :yahoo: Yes, I do have access to a 3d printer. why didn’t I think of that? I will try to make a replica of the power amp and mount it on the aluminum plate. :jammin: Thanks again -bjorn-If you have access to a 3d printer, you might be able to print a copy of the amp board, with the heatsink etc. and mount the print to the aluminium back plate, then it should displace the same amount of air volume in the speakers and have a very similar frequency response. That could be a way to continue to have the amps wall mounted, with these speakers.
Ok, so I have done the string trick for the second time. Hopefully I’ve done it correctly this time. Let me know if I’ve missed something.
It seems that I have reflection on a wood frame at the front ceiling cloud. And also, many places on the right-side slot wall. So now you want me to add insulation over all the spots, right? Then do the measurement again?
Thanks again
-Bjorn-
Hi Bjorn, looks like it's the side wall slats. Won't be the ceiling, as the path is not direct to the microphone. Consider a ray from the speaker, at that point the ray would bounce to the side wall again and then probably to the floor etc before getting to the microphone.
Just place a slab of insulation horizontally across the slats at the mix height and remeasure.
I would love to see this if you pull it off! :D DanThat’s insane! but brilliant! Yes, I do have access to a 3d printer. why didn’t I think of that? I will try to make a replica of the power amp and mount it on the aluminum plate.
John, that studio is gorgeous! Also, are you safe from the fires in Australia? It breaks my heart to see the nightmare that is happening down there :(
Bjorn, I totally agree with what Dan said regarding your cloud. It isn't in "line" with the path the audio would take on it's way from the speaker to the microphone. It has to be the side walls. Great detective work my dude!
Greg
Thanks Greg! :D Side wall noted.Bjorn, I totally agree with what Dan said regarding your cloud. It isn't in "line" with the path the audio would take on it's way from the speaker to the microphone. It has to be the side walls. Great detective work my dude!
Naice!:) I will remeasure with a slab of insulation horizontally across the slats at the mix height.Hi Bjorn, looks like it's the side wall slats. Won't be the ceiling, as the path is not direct to the microphone. Consider a ray from the speaker, at that point the ray would bounce to the side wall again and then probably to the floor etc before getting to the microphone. Just place a slab of insulation horizontally across the slats at the mix height and remeasure.
I have already started the process :D. So, I have a good amount of work ahead of me now. I will try to post as I move along the next few weeks.I would love to see this if you pull it off! :D
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1. Remove block from left speaker.
2. Insert / mount original untampered speaker on the left side and do a measure for reference.
3. Finish the fusion 360 replica of speaker amp and 3d print two copies.
4. Mount 3d copied speaker amp on the back plates and re-mount speaker inside enclosure with 15-20% Sorbothane deflection.
5. Re-mount speaker cabinet enclosure and with 15-20% Sorbothane deflection using the turnbuckles.
6. Put everything back in place.
7. Add slab of insulation horizontally across the slats at the mix height and remeasure.
Progress report: ( monitor-do-over ):
-
Both speakers is out of the front wall.
The cement block has been taken out of the left speaker
The Sorbothane has been taken out and recut and adjusted(some extra added and some replaced)
Almost ready for the 3d print of the speaker amps.
Wow. You're working hard and I'm blown away with that 3D modeling! Fingers crossed it works. It just doesn't make sense that after mounting the speakers, you lost all that bottom end. You should have gained bottom end, not lost it!
Also, is it hard to remove your speakers from the enclosures with the Sorbothane? And what about re-installing them?
Greg
New measurement done with new original speaker with amp mounted on the back.
I did not mount this with Sorbothane. Just wanted to make a reference measurement.
Find attached mdat file below.
https://drive.google.com/open?id=1C27Lk ... er9UD0rYpB
I added the last left speaker measurement in the file for comparison with new speaker vs speaker with concrete and outside mounted amp.
As you can see below its quite a difference.
Previous measurements
-
1. First measurement
Treatment: None
post: viewtopic.php?f=2&t=18593&start=45#p148378
mdat: https://drive.google.com/open?id=1aLSah ... WIHeCV7K8R
2. Second measurement.
Treatment: Soffit mounted speaker ( + concrete block added in speaker for weight ), ceiling cloud and side wall slats.
post: viewtopic.php?f=2&t=18593&start=90#p152103
mdat: https://drive.google.com/open?id=1WnNAl ... vEPFTKL7gM
3. Third measurement.
Treatment: Removed concrete block from right side speaker.
post: viewtopic.php?f=2&t=18593&start=90#p152142
mdat: https://drive.google.com/open?id=1C27Lk ... er9UD0rYpB
Thanks Greg. I just want to get this over with so I’m working as much as I can:). I’m glad you like the modeling. Just a few tweaks now and I’m going to print it. I hope it works as well.Wow. You're working hard and I'm blown away with that 3D modeling! Fingers crossed it works.
I don’t know Greg. This kind of things is not quite my area of expertise. Hopefully the fixes that are now being done will fix this. Check out the last measurement I did with the originale speakers (back mounted amp)It just doesn't make sense that after mounting the speakers, you lost all that bottom end. You should have gained bottom end, not lost it!
Yes, I use some time taking them out from the enclosures with the Sorbothane. I think I used about one hour for each enclosure taking them out. I used about two hours installing them back in each enclosure again. What takes time (for me anyway) is that I must take out each Sorbothane one by one to be able to get the speaker out. The Sorbothane is quite sticky and while compressed they are a bit hard to get out. When installing them back again I must do the same (one by one Sorbothane in the right place and make sure they are right compressed.). Anyway, I found a good tool that was quite handy for installing each Sorbothane bit in the right place. The god old “Extra-Long kitchen Tweezer Tongs”. This will be my third time I install them in the enclosure again so hopefully it will be the last for these speakers anyway. If you have other / better tips and tricks in regards of installing the Sorbothane just let me know. -Bjorn-Also, is it hard to remove your speakers from the enclosures with the Sorbothane? And what about re-installing them?
There must be something wrong with your measurement. The concrete block should only affect the bass, not the frequencies the tweeter is radiating. You loose nearly 10 dB over the wohle spectrum...New measurement done with new original speaker with amp mounted on the back. I did not mount this with Sorbothane. Just wanted to make a reference measurement. I added the last left speaker measurement in the file for comparison with new speaker vs speaker with concrete and outside mounted amp. As you can see below its quite a difference.
Thanks for the feedback. I will checkThere must be something wrong with your measurement. The concrete block should only affect the bass, not the frequencies the tweeter is radiating. You loose nearly 10 dB over the wohle spectrum...New measurement done with new original speaker with amp mounted on the back. I did not mount this with Sorbothane. Just wanted to make a reference measurement. I added the last left speaker measurement in the file for comparison with new speaker vs speaker with concrete and outside mounted amp. As you can see below its quite a difference.