• WANTED: Happy members who like to discuss audio and other topics related to our interest. Desire to learn and share knowledge of science required. There are many reviews of audio hardware and expert members to help answer your questions. Click here to have your audio equipment measured for free!

Measure your C50 in REW and tell us how your bass sounds!

KenMasters

Member
Joined
Apr 2, 2021
Messages
50
Likes
57
Location
Denmark
Oops I copied the subs from the previous person's post. But something still doesn't make sense. Arendal 1723 1s has a -3 dB point of 18 Hz. Your room is not small enough to be getting that much room gain. Normally to get 6 Hz, you need some kind of monster sealed sub (like JTR Captivator) with room gain. Measurement mics may not be accurate that low too.

The mic is a UMIK-1 with associated cal files. My living room is oddly shaped with low ceilings, side effect of converting an over 100 year old factory into an apartment building. The system is located between the end wall and a large support pillar, one sub in the far corner, one in the pillar corner - might be the reason? The dual Velodyne SPL-1000 Ultras I had before the Arendals managed to get down to 20Hz before dropping off precipitously in the same position.
 
Last edited:

Midnight Audiophile

Active Member
Joined
Jun 30, 2022
Messages
143
Likes
226
42" triangle - does that mean you're sitting 42" from the speakers?
Yes.
That's a very high clarity in that room, even at the dip. The clarity inversely correlates as it should with the RT 60 measurements. I'm told that for home hifi use it's generally preferred if the RT60 goes back up a little in the upper treble, which would suggest the clarity should come back down a little up there. It gives the room a little more airiness but I'm sure tastes vary.
I don't know how to make that happen, the system sounds good to me though : )

I'll work on some new measurements with the Yamaha NS-333s. So far I hear more detail with those than the Spektor 2s (more detail and spacial location on cymbals without being bright). Here's a couple more graphs from the old Spektor 2 measurements. I get the cleanest crossover with the subs at about 116Hz. I do like having control of both the high and low points with the Rolls units:

Screen Shot 2022-10-17 at 3.26.56 PM.png
Screen Shot 2022-10-17 at 3.11.54 PM.png
Screen Shot 2022-10-17 at 3.11.19 PM.png
 

darkinners

Member
Joined
Jun 27, 2020
Messages
13
Likes
9
The bass is really good, very clear, and well-defined. except for the 122Hz ringing that I couldn't get rid of due to space constraints and that a 580Hz dip that I think linked to it made the speaker's overall sound a little bit scooped.
C50.jpg
 

Midnight Audiophile

Active Member
Joined
Jun 30, 2022
Messages
143
Likes
226
Just saw this about a week ago and plan to update the calibration file for my UMIK-1 next round of measurements. Just an FYI for those that have been using a UMIK-1 for a while:

 

Fredygump

Member
Joined
Nov 3, 2022
Messages
78
Likes
66
Just to keep this going, here is some more data! I was looking for information about "Clarity" measurements, but found very little. I'd like to know what can be extrapolated from this data.

Clarity:

1667441460687.png


Frequency response and distortion from the same measurement:

1667441701035.png


Speakers are prototypes of my Genelic W371A inspired design. It's an active 4 way design. Each cabinet has a 10" rear firing ported subwoofer, 12" sealed front firing woofer, and a 12" B&C coaxial driver for mids and highs.

*These measurements were taken while testing the integration of the 4 low frequency drivers, so the full range data is not necessarily representitive of the finished speaker.

It was made for bass, and the bass is good!
 

chych7

Active Member
Joined
Aug 28, 2020
Messages
276
Likes
422
Just to keep this going, here is some more data! I was looking for information about "Clarity" measurements, but found very little. I'd like to know what can be extrapolated from this data.

Looks pretty good. The clarity dip in the upper bass region can point to room-related bass issues/reverb or SBIR issues, which some bass trapping could help with.
 

ernestcarl

Major Contributor
Joined
Sep 4, 2019
Messages
3,106
Likes
2,313
Location
Canada
42" triangle - does that mean you're sitting 42" from the speakers? That's a very high clarity in that room, even at the dip. The clarity inversely correlates as it should with the RT 60 measurements. I'm told that for home hifi use it's generally preferred if the RT60 goes back up a little in the upper treble, which would suggest the clarity should come back down a little up there. It gives the room a little more airiness but I'm sure tastes vary.

@Midnight Audiophile

One way to increase reflection-decay (RTx) in a dry room (which incidentally reduces clarity a bit in the HF range as well) is to simply add more channels through multi-channel upmixing. It should increase the overall sound "envelopment" bubble and that "airiness" feel.
 

Toltek

Member
Joined
Dec 12, 2019
Messages
26
Likes
24
It is not even a room, just an open space in the basement, weird shape, low ceiling, no treatment, single sub, probably 11 ft from LP. I guess I just got lucky, bass sounds good to me, but limited in volume, second sub is supposed to arrive today.View attachment 237654View attachment 237655
With second sub, all measurements at MLP

Response with psy smoothing
d3 psy response.jpg

Bass only, no smoothing
d3 bass only.jpg

Distortion
d3 90db distortion.jpg

Wavelet
D3 wavelet PEQ.jpg

Clarity
D3 clarity.jpg
 

Fredygump

Member
Joined
Nov 3, 2022
Messages
78
Likes
66
With second sub, all measurements at MLP

Response with psy smoothing
View attachment 242255
Bass only, no smoothing
View attachment 242253
Distortion
View attachment 242256
Wavelet
View attachment 242257
Clarity
View attachment 242254
How did you integrate your subs? Are they controlled by an AVR with room correction, or are you doing it all manually, like with a MiniDSP? I'm curious because I've been doing a lot with DSP on my speaker project.

Your low frequency response looks good, but it might be worth looking into that distortion at low frequencies. I know low frequency distortion is not supposed to be audible, but there might be something undesireable going on that is fixable. Probably the first thing to try is testing at a lower level, just to see if that distortion drops.

Based on my recent experience, I'm thinking it might be caused by subs with small ports being pushed pretty hard? In my DIY system, which is absolutely ridiculous and experimental, I was able to reduce the low frequency noise by doubling the port area of one of my subs. I had previously measured ~10% noise (-30dB) from 20-35hz in the measurements I posted earlier. My result didn't look all to different from yours. But with the new cabinet I just built, that number has dropped to 2-3% making that low frequency noise peak essentially disappear.

I'm curious about what you find. It's all for science, right? Oh, and for the bass! :)
 

Toltek

Member
Joined
Dec 12, 2019
Messages
26
Likes
24
I have two small subs in a relatively large and odd shaped open floor in the basement. 90db was deliberate, at 80db distortion in the subbass drops to -35db. Above 40 Hz distortion is good enough for me. On some torture tracks from BASS!!! thread I don't hear any increase in distortion even when it's just too loud for me. On this track Copland I measured 105 db peaks with 90 db average and it sounded natural and fabulous. Subs are commercial: SVS micro 3000, I use minidsp SHD, with individual delays, gains and minor PEQ for each, sum them to mono, 80Hz LR24, then run Dirac on top of that. Speaker are just some yard sale find from last millennium. I am ashamed to name them, because the only mention on this forum I could find is that there are worse than modern speakers which you could buy for $85. I still like them though, they have been my favorite for the last 15 years.
room_ft.jpg
 

Fredygump

Member
Joined
Nov 3, 2022
Messages
78
Likes
66
I have two small subs in a relatively large and odd shaped open floor in the basement. 90db was deliberate, at 80db distortion in the subbass drops to -35db. Above 40 Hz distortion is good enough for me. On some torture tracks from BASS!!! thread I don't hear any increase in distortion even when it's just too loud for me. On this track Copland I measured 105 db peaks with 90 db average and it sounded natural and fabulous. Subs are commercial: SVS micro 3000, I use minidsp SHD, with individual delays, gains and minor PEQ for each, sum them to mono, 80Hz LR24, then run Dirac on top of that. Speaker are just some yard sale find from last millennium. I am ashamed to name them, because the only mention on this forum I could find is that there are worse than modern speakers which you could buy for $85. I still like them though, they have been my favorite for the last 15 years.View attachment 242485

Cool. Thanks.

Building a small sub that can extend down to 20hz is not trivial, so you're going lower than I would expect. I assume you used the MiniDSP to boost the lowest frequencies? SVS shows response dropping off rapidly at 30hz. That's probably why you're getting that higher noise level?

One thing I think I've learned is that if you want to do multiple subwoofers (i.e. like having 4), you don't need all of them to play down to 20hz to get good results. The problem area, atleast for me, is from 50hz to 100hz.

So I guess I'm saying that if at some point you want to take it to the next level with a 3rd or 4th sub, you can happily build on what you already have. Just add a single big sub for the 40-20hz + subsonics, and put the small subs back to a more natural response curve. That is all you are ever going to need.

My project (It's still a prototype!). The front sealed woofers play from 120hz to 50hz, and the rear ported sub plays from 20 to 100hz. I put them all in the same cabinet, because I saw Genelec doing something like that, and I thought it looked really clever! And it works. But of course it is a lot more common to place the subs around the room.

20221105_214028_resized.jpg
20221106_112607_resized.jpg
 

ozzy9832001

Senior Member
Joined
Feb 19, 2023
Messages
404
Likes
257
clarity.jpg

Here's mine. Definitely not as good as some of you guys. Still working on getting some more bass traps. This is from my MLP which is only 42" from speakers.
 
OP
T

Tim Link

Addicted to Fun and Learning
Forum Donor
Joined
Apr 10, 2020
Messages
722
Likes
638
Location
Eugene, OR
OP
T

Tim Link

Addicted to Fun and Learning
Forum Donor
Joined
Apr 10, 2020
Messages
722
Likes
638
Location
Eugene, OR
View attachment 267822
Here's mine. Definitely not as good as some of you guys. Still working on getting some more bass traps. This is from my MLP which is only 42" from speakers.
That's amazing! Looks like it might need a little less absorption up above 1k and a bit more in the 200 to 600 Hz range.
 
OP
T

Tim Link

Addicted to Fun and Learning
Forum Donor
Joined
Apr 10, 2020
Messages
722
Likes
638
Location
Eugene, OR
Here's my latest measurements since I moved. This room is about 20 feet long and 12 feet wide. I'm sitting about 12 feet back from the corner horn woofers and 10 feet from the main speakers. Measurement was taken from this position. This sounds pretty good (actually really great in some ways!) but I need some help from acoustics in the range from 200 to 800Hz.
I don't have any acoustic treatments in here yet. Not falling below 10dB anywhere is a new record for me! It's not even close to what some of you guys are getting. One thing I think is good about this is the relative evenness. This room has a good balanced sound with a nice combination of brightness and clarity. Another great thing about this room is it is highly symmetrical in the front end, it's perfectly square at the front with no windows or doors for the first 6 feet, and then there's just a solid door on the right. On the left there's about 10 feet until a sliding glass door. So this room has really good balanced imaging.

FamilyRoomClarity.jpg


Here.s the RT60 measurements.
FamilyRoomRT60.jpg
 
Last edited:

ozzy9832001

Senior Member
Joined
Feb 19, 2023
Messages
404
Likes
257
That's amazing! Looks like it might need a little less absorption up above 1k and a bit more in the 200 to 600 Hz range.
Interestingly enough, if I open my curtains, the response is worse. Not by much. I have 2 panels on the front wall behind the speakers, which probably isn't the best place for them.
clarity.jpg
 

MengW

Member
Joined
Jun 30, 2022
Messages
63
Likes
44
Another interesting topic, enjoying the ASR forum more and more. In the past few years, I have never paid attention to this C50 value.

Now, there is only one rented small room of 13 square meters, I think that the W371+AVAA should be the best and easiest and expensive solution for me, and then they did give me this magical and amazing result.

Found out these measurement results, fyi.
1678362965757.png

1678363080355.png

1678364194083.png
1678363523909.png
 
OP
T

Tim Link

Addicted to Fun and Learning
Forum Donor
Joined
Apr 10, 2020
Messages
722
Likes
638
Location
Eugene, OR
Another interesting topic, enjoying the ASR forum more and more. In the past few years, I have never paid attention to this C50 value.

Now, there is only one rented small room of 13 square meters, I think that the W371+AVAA should be the best and easiest and expensive solution for me, and then they did give me this magical and amazing result.

Found out these measurement results, fyi.
View attachment 270427
View attachment 270428
View attachment 270432View attachment 270431
That's super high. Over 40 dB at 400Hz! How far was the microphone from the speakers when you took this measurement?
 
Top Bottom