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

[Tim Link]

Aside from what correlation Tim is hoping to establish, I’m interested in what clarity values mean for the home audio person in general. Most of what you find on the web deals with concert halls. Example: This is a great site for listening to different Clarity 80 values for the big spaces - https://www.concerthalls.org/?page_id=151

Googling optimum Clarity values I found this table –
OPTIMAL CLARITY in dB
-1.6 < C80 < 1.6 Instrumental music
-2 < C80 < +2 Symphonic music
0 < C80 < +4 Opera
C50 > +3 Speech
https://www.acoustex.de/fileadmin/user_upload/industry_acoustex_12dodicifacce_R02.pdf

Data for my Left and Right speakers shown. The red line in my REW graph represents C50. The green line is C80. My listening room is a large open floor plan. The “room” is ~ 6K ft^3 with openings to adjacent rooms. The mic was ~ 8 ft away from the speakers. My clarity values are higher than what is recommended in the above table.

I would be interested to hear what others consider a preferred C50 or C80 value and if these clarity values are correlated to other room attributes.

View attachment 129078View attachment 129079

I like those samples on concerthalls.org! The lower C80 is certainly appropriate in larger halls for producing music. I think I liked the two lowest measurements the best for that trumpet example. Of course it depends on what they're trying to do with the music but I like hearing a large reverberant music hall effect. The question is how much of our smaller listening room reverberance do we want to add on top of the reverberance that's already in the recording when we play it back through speakers?

It is interesting to see in your relatively large space that there is a dip in clarity between about 200Hz and 1kHz. I just looked at someone's untreated space smaller than yours and they had a dip in clarity that was centered a little higher from around 500Hz to 1.5kHz.

 

[dasdoing]

I get quite a variance in the bass depending on how much delay I use (treated room btw)

 

[chych7]

Throwing my system into the ring below.
I have a significant number of acoustic treatments (8x 24"x48"x4" corner bass traps, 8x 24"x48"x2" broadband absorption, diffusers, and various other things) and my results are below. 3 subwoofers (1 is a mid-bass sub) integrated with miniDSP + MSO, and Audyssey XT32 for the rest. You can see that my clarity values are quite high, and RT60 quite low (perhaps too low, but I don't feel that the room is dead sounding). This does give me extremely good imaging for the mid/upper freqs.

My bass quality, IMO, is excellent. Extremely satisfying, tight, clean, impactful bass. After running many calibrations and playing with my system, my opinions on what contribute to good bass quality are:
- Smooth SPL vs. freq, get rid of peaks/nulls as much as possible
- Reduce excessive RT60 times; lower freqs can be >2 sec without treatment in poor rooms. I still have high RT60 for lower bass, but it's much better than pre-treatment (>2 sec).
- Ensure group delay is managed, nothing over 50 ms in the bass region. I've had some calibrations where the EQ resulted in high group delay (~100 ms) in the mid-bass. This was audible, the bass didn't sound as well integrated.
- Use a near-field mid-bass subwoofer for extra tactile response. It makes a difference, especially for HT use, but also for music. Certain instruments like drums sound more convincing when you can also feel their impact, which is in the mid to upper bass range.
- Ability to tune the bass. Not all source material are recorded/mastered the same, and can need adjustment to get the right amount of bass. I use Audyssey's Dynamic EQ and reference level offset to tune it further (on top of a Harman curve, which is what I have below as the initial response).




Clarity C50:

SPL:

RT60 Topt and fitted T60:

Group Delay:

 

[Flaesh]

Good thread!)
I prefer D50, which has a limit value of 100%. I think actual D50 is

while D is calculated from the C and the shape of both curves is (almost) the same (below some old grafs, forgot details )

Speakers (~as on avatar) in corners, DBA subs, about 14' to MLP.
Here is the room 14'W*30'L*10'H

Double bass array. Low Q subs. [Quasi]plain wave radiation?

Hi there! Briefly: Here is the room 14'W*30'L*10H. Speakers not shown as their location may vary. Subs (2F+2R) placed as expected at half of room height. Here is measured LF response approximately at "sweet spot". As always (unless otherwise specified) no smooting, without eq\correction, with...

www.audiosciencereview.com

 

[Flaesh]

It doesn't make sense at bass frequencies

Correlation definetly exist. Not everyone has the opportunity to listen to D>90% C50>10-15 dB bass and live with a disgusting inarticulate booom for years.
For example, owner of this

says it's good, but to me his "bass" is unlistenable.

 

[chych7]

Correlation definetly exist. Not everyone has the opportunity to listen to D>90% C50>10-15 dB bass and live with a disgusting inarticulate booom for years.
For example, owner of this
View attachment 237519
says it's good, but to me his "bass" is unlistenable.

That's some really odd C50, heavily biased to mids/highs. High frequency reflections look like they are completely killed off. Was the room heavily treated using acoustic foam?

 

[Flaesh]

Was the room heavily treated

Yes, dedicated room with one audiophile chair, absorbing ceiling, some thin absorbing panels on walls and nothing for LF
p. s.: normalized wavelet:

 

[Midnight Audiophile]

I’m in the process of slightly repositioning and retuning my system so these are some old measurements. The room is 10.5’ x 19 with 8’ ceiling. Carpeted and padded concrete floor and some room treatment, brick wall behind the listening position (with bookcases and some treatment).

System:

Dali Spektor 2s on Kanto SP6HD stands on coffee table.
Aiyima A07 amp with 32v 10 amp PS (adjustable from 48v).
ifi Zen Signature DAC.
Rolls SX45 Crossover (for high pass on the mains).
Rolls SX95 Crossover (for the 2 subs and I run them in stereo).
Theatre Solutions slimline 8” sub (under the couch).
6.5” Acoustic Audio PSW6 sub with Dayton Audio DCS165-4 Classic sub driver (under the coffee table).

42” triangle from Spektor 2s on coffee table to LP.
Currently in the process of setting up Yamaha NS-333s in place of the Spektor 2s.

I’m happy with the bass. I believe the large dip at 400Hz is from the couch and brick wall. I’m still learning my way around REW so I don’t fully understand a lot of the measurements. Any enlightenment would be welcome.

 

[KenMasters]

I think my bass sounds pretty good, I'm sure my room could be better, but it's a general purpose living room so can't go too crazy with the room treatments. Room itself is about 4m x 7m, speakers along the long wall as the dinning area takes up the other half of the room. I have 2 x 120x60cm 10cm deep absorbers placed behind the speakers as well as floor to ceiling bass traps (220cm x 60cm, 40cm deep) with a 150cm x 100cm 10cm deep absorber on the back wall. Otherwise furnished as a typical living room - TV, coffee table, sofa etc.

 

[Flaesh]

Room itself is about 4m x 7m, speakers along the long wall as the dinning area takes up the other half of the room.

What is the distance from speaker(s) to mic?

 

[Tim Link]

I think my bass sounds pretty good, I'm sure my room could be better, but it's a general purpose living room so can't go too crazy with the room treatments. Room itself is about 4m x 7m, speakers along the long wall as the dinning area takes up the other half of the room. I have 2 x 120x60cm 10cm deep absorbers placed behind the speakers as well as floor to ceiling bass traps (220cm x 60cm, 40cm deep) with a 150cm x 100cm 10cm deep absorber on the back wall. Otherwise furnished as a typical living room - TV, coffee table, sofa etc.

View attachment 237538View attachment 237539

The measurements suggest it should sound good - even clarity throughout the range, no major peaks or dips in the bass, extension down to 6Hz! I don't know what the Psy means. 6Hz seems too good to be true.

 

[KenMasters]

What is the distance from speaker(s) to mic?

L+R speakers are roughly 2.2m from the MLP.

 

[chych7]

The measurements suggest it should sound good - even clarity throughout the range, no major peaks or dips in the bass, extension down to 6Hz! I don't know what the Psy means. 6Hz seems too good to be true.

Something seems fishy, no way you're getting 6 Hz with those subs

Theatre Solutions slimline 8” sub (under the couch).
6.5” Acoustic Audio PSW6 sub with Dayton Audio DCS165-4 Classic sub driver (under the coffee table).

 

[KenMasters]

The measurements suggest it should sound good - even clarity throughout the range, no major peaks or dips in the bass, extension down to 6Hz! I don't know what the Psy means. 6Hz seems too good to be true.

"Psy" - Psychoachoustic.

Here's a measurement of the subs alone, no smoothing:

Something seems fishy, no way you're getting 6 Hz with those subs

Those aren't my subs, I have two Arendal 1723 1S' (bookshelves are KEF LS50 Metas).

 

[Tim Link]

I’m in the process of slightly repositioning and retuning my system so these are some old measurements. The room is 10.5’ x 19 with 8’ ceiling. Carpeted and padded concrete floor and some room treatment, brick wall behind the listening position (with bookcases and some treatment).

View attachment 237532

System:

Dali Spektor 2s on Kanto SP6HD stands on coffee table.
Aiyima A07 amp with 32v 10 amp PS (adjustable from 48v).
ifi Zen Signature DAC.
Rolls SX45 Crossover (for high pass on the mains).
Rolls SX95 Crossover (for the 2 subs and I run them in stereo).
Theatre Solutions slimline 8” sub (under the couch).
6.5” Acoustic Audio PSW6 sub with Dayton Audio DCS165-4 Classic sub driver (under the coffee table).

42” triangle from Spektor 2s on coffee table to LP.
Currently in the process of setting up Yamaha NS-333s in place of the Spektor 2s.

I’m happy with the bass. I believe the large dip at 400Hz is from the couch and brick wall. I’m still learning my way around REW so I don’t fully understand a lot of the measurements. Any enlightenment would be welcome.

View attachment 237533View attachment 237534View attachment 237535View attachment 237536View attachment 237537

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.

 

[Tim Link]

"Psy" - Psychoachoustic.

Here's a measurement of the subs alone, no smoothing:

View attachment 237647



Those aren't my subs, I have two Arendal 1723 1S' (bookshelves are KEF LS50 Metas).

That's some seriously deep bass response!

 

[Toltek]

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.

 

[Flaesh]

second sub is supposed to arrive today

Congrats!))

 

[chych7]

"Psy" - Psychoachoustic.

Here's a measurement of the subs alone, no smoothing:

View attachment 237647



Those aren't my subs, I have two Arendal 1723 1S' (bookshelves are KEF LS50 Metas).

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.

 

[Tim Link]

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.

Yeah, what's going on in there? That's crazy bass!