:thu:
We should do some REW tests about now!
- Stuart -
New (Small Home Studio) Build, Norway
Originally posted at johnlsayers.com, topic 18593.
Yes. I will finish up the speaker mounts first and then run some more testing :D:thu: We should do some REW tests about now! - Stuart -
Some updates. Finishing up the back of the room. Still missing the corner base traps though.
Things are moving along quite nicely. Front wall nearly finished :snack:
Any updates?
Greg
Hi Greg I have been occupied with other stuff the last few weeks unfortunately. Back in business now though :yahoo: I have this week finished the last part of the ceiling at the front. Now Im currently working on the first part of the cloud. Will most likely finished it this week. I will try to post as I move along :)Any updates? Greg
Hi!
Looking good! Nice to see there's still progress being made.
Keep those pics coming if you can!
Dan
Hi Dan Thanks for taking an interest :D Still working on the clouds. Here is som updated pics The store was out of two lights so I had to order more. Put a lid on in the mean time:)Hi! Looking good! Nice to see there's still progress being made. Keep those pics coming if you can! Dan
Hi
New update: :snack:
Almost finished with the first front cloud. A few adjustments still needed. Also waiting for the last two lights that’s coming in the mail. I will hopefully finish this one up in the next few days and start on the last back cloud. :jammin:
Looking really good Bjorn!
Can I ask the rationale behind your "slotted" side walls, are they evenly spaced/sized lengths of timber? I assume it's some kind of non-numeric scattering?
Dan
Thanks Dan! :D As shown in previous posts the slot side walls are spaced timber. See the picture below. When it comes to the rational thinking and calculations we need to ask Stuart if he can clarify a bit. I hired some hours from him to design the room tuning after the last measures I did. You can read about it in the earlier posts. http://johnlsayers.com/phpBB2/viewtopic.php?f=2&t=18593&start=45. Im not sure if his active on this forum anymore though.Looking really good Bjorn! Can I ask the rationale behind your "slotted" side walls, are they evenly spaced/sized lengths of timber? I assume it's some kind of non-numeric scattering? Dan
Hi again Dan I see now on other posts that Stuart has left the building and will most likely not return anytime soon. I have attached some measurements of my slot wall and some race trace. Hope that can bring some clarification to you question. :) - Bjorn -I assume it's some kind of non-numeric scattering? Dan
New Updates. Missing lights installed. New computer build and the last back cloud mounted. Corner base trapps to go. :thu:
Computer mount:
Check out this badass heat sink for the computer processor. Very silent :D.
Do you have any mdat to share to show us the acoustic changes with each new device you installed?
Looks beautiful!
Greg
Thanks Greg, really appreciate it :D. I dont have an mdat for each new change. I was waiting with the next measurement while I was finishing up the cloud construction. I will do some measurement now before I install the corner base traps and share with you guys BjornDo you have any mdat to share to show us the acoustic changes with each new device you installed? Looks beautiful! Greg
Merry Christmas everyone :D
New measurement done. The measurement was done based on description here:
http://www.johnlsayers.com/phpBB2/viewt ... =3&t=21122
My gear setup:
Mic: PreSonus PRM-1
Sound level meter: Extech-407732
Calibration:
Calibration REW to sound card done as explained in the REW help section. Calibration file is the same as done on a previous measurement.
Any help / comments for interpret the REW graphs will be highly appreciated.
Find attached mdat file below.
https://drive.google.com/open?id=1WnNAl ... vEPFTKL7gM
Note
You can find my previous measurement here
viewtopic.php?f=2&t=18593&start=45
Calibrating levels
Left side speaker level check
Right side speaker level check
Measurement
Your RT60 is very low (often living around 50ms). I understand your room is small but that seems extremely low now. And the <100Hz range seems to have really dropped off with your new measurements. Was there any changes made to your speakers? Do you own a subwoofer?
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
Find attached some measurement comparisons below. The first measurement is before the room treatment (flush mounted speakers, slots and celling clouds).
Second measurement is after installation of room treatment. Still haven’t build the back corner base traps.
COMPARE SLS
First measurement waterfall
Second measurement waterfall
First measurement spectogram
Second measurement spectogram
Hi Greg. I will try to research the reflection. The changes to the speakers is that they are now flush monted. I do not own a sub. BjornYour RT60 is very low (often living around 50ms). I understand your room is small but that seems extremely low now. And the <100Hz range seems to have really dropped off with your new measurements. Was there any changes made to your speakers? Do you own a subwoofer? 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
I've looked at your measurement and I have a stupid question: did you seal the Presonus Eris E5 back after removing the amp from it? I've looked at the specs and they should go down to 53 Hz. The loss of bass and the deep notch at 90 Hz looks a bit like you have an acoustic short circuit. But it could be a nasty room mode, too. Also, it seems like the amp is not inteded to be removed as far as I can tell from the pictures on it's product site. Does the amp supplant a siginifcant amount of air in the cabinet of the speaker? Because if so, you might have detuned the bass reflex resonance frequency, which will also result in a bass roll off.
So, regarding the low RT 60 let’s go in details of what has been done after first measurement.
First. After the first measurement and before the room tuning started the room was a bit too "dry" (slightly too dead). It was almost uncomfortable to be in it. felt like a pressure feeling on the ears. It's a very small room, so the goal was to increase the decay times a bit. Sins the room is built inside out I added I added more reflection surfaces around the room, and some other stuff to deal with a few early reflections, plus some targeted bass trapping for the modal issues (that is coming next).
Anyway, this is what Stuart suggested and I hired a few hours from him to help me with the design. He ended up designing the soffit mounting of the speakers, side slot walls. He was also the one to suggest that I mount the back side of the Eris speakers on the wall.
Anyway today the room feels much better and sounds pretty good. But as we can see the measurements are still not so good.
Could be I thrusted him to blindly and are now suffering the consequence. :oops:
My last respons was a bit unaccurate. Due to loss in weight of the speakers when removing the amp I had to add a 2 kg concrete blocks inside the speakers together with a thick aluminium back plate. The weight was added due to the speaker is floated on carefully calculated Sorbothane pads inside the enclosure, and the enclosure is then floated on different Sorbothane pads, that are compressed to the exact tension using the turnbuckles. This was also something Stuart asked me to do. After removing the amps, the weight was to low to get the tension right. So, I got the speaker weight to about 5,7 kg for each speaker. The tension could be a bit off sins Stuart left this site and can’t be reached anymore. The actual tension based on his calculation was the last bit I was waiting for from him. But as other people also has experienced hi did not follow though until the end on my project either, so I am missing that part and had to improvise.Was there any changes made to your speakers? Greg
Thanks TomessAI for chipping in. Yes as you can see I sealed the back side with a thick aluminum plate. I will contact the manufacture of the speakers and ask them about the amp. Could be that I must change both speakers to something more suitable. :evil: I now feel that this was quite a draw back sins I am so close to finish. But what can you do. :cry:I've looked at your measurement and I have a stupid question: did you seal the Presonus Eris E5 back after removing the amp from it? I've looked at the specs and they should go down to 53 Hz. The loss of bass and the deep notch at 90 Hz looks a bit like you have an acoustic short circuit. But it could be a nasty room mode, too. Also, it seems like the amp is not inteded to be removed as far as I can tell from the pictures on it's product site. Does the amp supplant a siginifcant amount of air in the cabinet of the speaker? Because if so, you might have detuned the bass reflex resonance frequency, which will also result in a bass roll off.
This is probably what totally screwed up your low end. The volume (area) of the speaker cabinet has now been drastically reduced which completely changes the performance of the speaker. If the speaker would have sounded equally as good with a volume (area) that small, the company would have built it that size. We all want our material goods smaller in our lives, but when it comes to speaker enclosures, there are rules of physics that we just cannot change. Again, I'm guessing, but I bet this loss of volume (area) is the cause of the bottom end drop off. I also would have used a similar type of wood as the original construction to cover the hole on the back of the speakers as the aluminum could be messing with things as well. Your construction looks great and you should be proud! Don't be discouraged. Stuart is a brilliant man. Ideally what should have happened was a Sorbothane calculation adjustment based on the new weight of the amp-less speakers. GregDue to loss in weight of the speakers when removing the amp I had to add a 2 kg concrete blocks inside the speakers together with a thick aluminium back plate.
Good point. Even though the amp itself takes a bit of space the concrete block takes a bit more. That could be the cause. I will take out the concrete block from one speaker and do a measurement so we can compare one speaker with the block and one without.This is probably what totally screwed up your low end. The volume (area) of the speaker cabinet has now been drastically reduced which completely changes the performance of the speaker. If the speaker would have sounded equally as good with a volume (area) that small, the company would have built it that size
Well the back hole is already covered with the amp back plate originally. Witch is aluminium. So I guess that covering the hole with another aluminium plate should work right?.I also would have used a similar type of wood as the original construction to cover the hole on the back of the speakers as the aluminium could be messing with things as well.
Thanks Greg. I’m just get frustrated when I must do over stuff I thought was after the book.Your construction looks great and you should be proud! Don't be discouraged.
I know he knows his stuff and then some, just frustrating sometimes when people do not complete what was promised. Anyway, enough about Stuart. I should have done measurements right after the speaker weight enhancement to check. So, note to self: "don’t fill speaker enclosers with concrete". Anyway, when I remove the block from the speaker, I will probably be way of the original Sorbothane calculation. I am bit unsure how this is calculated and how to tighten the turnbuckles for correct tension. This is the types and setup I have used: The weight of the speakers without the backside (amp) is 2.72 kg each + the aluminium back plate. The cabinet for mounting the speaker in the wall weight are 7 kg each. Bottom pads (under the speaker, inside the enclosure box) (40 duro Sorbothane, 1" thick) Side pads (40 duro Sorbothane, 1" thick): Top Pads (40 duro Sorbothane, 1" thick): Base pads (under the entire enclosure box), (30 duro Sorbothane, 1" thick): Thanks again :D BjornStuart is a brilliant man. Ideally what should have happened was a Sorbothane calculation adjustment based on the new weight of the amp-less speakers.
Now I have removed the concrete block on the right speaker, put everything back in place and made a new measurement.
Find attached mdat file below.
https://drive.google.com/open?id=1cCvlH ... 2l3ePLvvQX
Bjorn
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. DanI will probably be way of the original Sorbothane calculation. I am bit unsure how this is calculated and how to tighten the turnbuckles for correct tension.