Hi Guys,

I've been working in my studio for around 2 years now doing recording, mixing and mastering jobs. Im very happy with the acoustics and sound i am getting. Obviously there is always room for improvement!

Right now, my biggest issue is the the amount of low end i am getting. The low end is very controlled with no notable spikes. For mixing duties its fine, but for recording, i often go to the limit when working on bass drums (everything else is fine). My Sub starts to distort rather easily. When listening at normal volumes its fine, but once in a while I have to go loud for the bass area and the clients.

Room is around 5m x 8m x 3.5m, so a lot of volume!
Sub: Dynaudio 9s Sub
Tops: Geithain RL940

The Sub is not sufficient to provide enough bass in this big room. My question is would it be better to have 2 Dynaudio 9s Subs or to get 1 more powerful sub?
Dynaudio have another sub (18s) which has 2 9" speakers. Will that be superior to 2 9s subs? I would rather have 2 smaller subs that i can place better in relation to modes than one more powerful sub, if they have enough power.

https://www.google.com/url?q=https:/...iPW_rfJTCf81zP

Not sure what is going on, but your subwoofer(s) in a control room environment, shouldn't be working real hard. The sub is just there to help "fill in" the low end that your main monitors either aren't able to produce or that you have intentionally high-passed to allow them to produce a cleaner output at higher SPLs.

Yes that makes sense!
Now the question is, can i move more air with 2x 9" subs or better have 1x12" or something like that?

The quote above explains this quite well. When recording the peaks are a lot higher than when mixing and mastering. Listening at 85db average means peaks that go well over 100dB spl. A small 9" sub can't reproduce these frequencies with no distortion! I have to add that my sub plays down to 22Hz and you can hear it!! There is a very steep cut under 22Hz, but when recording, it really moves that speaker at very low frequencies!

I'd say 2 10's or 12's, one positioned under each main. I have 2 10's and havent had any trouble

Your current sub (Dynaudio 9S) has a max SPL of 106dB, not sure the measured distance, but most often this is at 1m.

I am a bit confused of what you are after. Are you in the Control Room and listening to the live kick drum from the isolated live/tracking room and having trouble as you feel the subwoofer cannot reproduce the SPL you desire? If your CR is properly isolated from the tracking room, this should not be an issue. You would be able to monitor the tracking in real-time (live) at even a very low volume effectively and accurately.

If you just want a loud (impress the client) mix in the CR, then maybe you need more ooomph from the sub(s)? If the tracking mix is right, then one part (kick or bass guitar or otherwise) should not be poking through and significantly louder than everything else.

Or am I missing something here?

Adding one more sub to the party will gain you 6dB of level, at best. Depending on placement that realistically might look like 3-4dB.

Are you measuring with REW? Positioning of subs can make a very big difference to how much SPL is delivered to the listening position. A floor-wall-wall corner will give you the most effective room gain (you can also model this in REW).

That all said if you wanted to set the bar really high, like THD @-40dB @20hz and 105dB- quad 18's with 4kW or more of power wouldn't be crazy. Distortion really shoots up in the lowest octaves for subs and it takes a lot here.

You can measure THD in REW.

Is this the room we are discussing? (dec 2017 thread)

Pls post an mdat with description of your current treatment and spkr/ listener positions.

Best

What kind of walls?


BTW Your earlier measurements was fairly distorted...

Thanks for your input! I think what your missing is that my room is more than 120m3 in volume! You need quite a bit of low end in such a room.

Yup thanks for that tipp. Thats what i was expecting. I checked different subs in the same price range and size and they all seem to pretty much have the same spl readings. the double 9"s from dynaudio has around 5db more
fits right in to the equation. I'd rather have 2 separate subs i can place where i want them

Pretty awesome research!! :D
Yes that is the same room. Quite some things have changed since, but the most important things (the room and speakers) have stayed the same for sure!
Right now the question is more about getting more bass into the room before distorting than the overall sound, but i'm really happy you have chimed in.



One thing i realized was that most of the distortion from the sub is at really low frequencies. Between 20-30Hz is the most distortion. Its a ported sub, it goes down really low, but it just doesn't have much power down there anymore. One thing i could do is just use my crossover to low cut the sub under 30Hz (which would be a pity, since it can reproduce it).
I've done a 15Hz Low Cut it and it did already help! It also cleaned up the frequency crossover to the tops actually!

Once i get to it, i will make some new measurements, but it might take some time!
Not really sure how to read the distortion graphs correctly. Will try that next time.

It's just a matter of SPL for the space. If the room is larger, you need more SPL to play the music "louder" and to "fill" that space. You can group subwoofers as well in an "array" of sorts, but placed where is best in the room acoustically. In my room, which is about 185m3 (25 feet wide x 20 feet deep x 13 feet high) I don't have the problem you are having in your space. I have Neumann KH420 mains and a KH870 sub. The sub really doesn't do a whole lot, other than fill out the low end some when needed and when it is engaged it does allow the mains to play at higher SPL. I can play my monitors/sub at quite loud volumes without issue or noticeable distortion. My room was purpose-built and acoustically designed as a RFZ and performs very well as such.

I think your issue is one of 2 things 1) You need more SPL at a cleaner distortion level and/or 2) Your room needs some additional tuning and isn't allowing the sound to be produced evenly across the spectrum (acoustic inefficiency?)

My 2 cents. And, my opinions only based on what I have read on your situation. Just trying to help.

Hi SRS,
Thanks for your Input. Well the KH870 is a whole other beast! It can produce 116dB spl, which is quite amazing.
Is your room really 5500m3 in volume? That would be huge. You mean 550m3, which is still huge for a CR??

Yes, i need to produce more and cleaner spl at bass levels. My space is already quite tuned. There is always room for improvement, but i have quite some rockwool in this space already. I tried moving the sub closer to the front wall, but got very little change. Slightly more bass below 40Hz, but a few more valleys higher up in the frequency response. Right now my sub is around 50cm from the front wall. It seems it gives me the most linear response.

I made some new measurements, because i was interested in the distortion measurements.
I have a minidsp balanced in my signal chain doing mostly crossover duties. I had the same distortion issues before i added the minidsp (i only got it around 2 weeks ago).
The measurements show the sub with different lo and high cuts and as reference also the Left Top speaker.
Its interesting that the sub exibits the most distortion when the highcut is set at 80Hz. Turning off the High Cut shows better distortion characteristics. Thats very interesting to me. Also the Tops have a lot less distortion in the low end, but obviously don't produce as much down there.

I would be very interested how you guys interpret these measurements. Have never looked at distortion measurements before.

Also one thing i noticed was that the subwoofer seems to have some sort of limiter eventhough it has no dsp what so ever! When i reach the distortion in the subwoofer i can turn it up as far as i want, it doesn't go louder or distort more. When i turn the volume down fast there is a sort of release time before the volume goes up again.
Can this have to do with the distortion?

EDIT: Ok i just realized i made a noob mistake and uploaded only 1 measurement and its not even from the Sub so i deleted the measurement. Unfortunatly ill be gone for a few days and can't redo the measurement till then. Guess this will have to wait. :/

My math was WAY off! Sorry bout that. My room is much less than that at about 185 cubic meters. I think I did the math right this time...? But still large for a control room. It’s 25 feet wide by 20 feet deep with a 13 foot ceiling. But a RFZ non-parallel boundaries in a all/any direction. So tough to really measure the volume accurately. And yes, the Neumann KH420 and KH870 combo fills the room with substantial and clean SPL.

Yes that makes a lot more sense now.
And then your system is quite powerful for the room! Do you use the CR for recording of drums as well?

Thats where i have my problems. For mixing and mastering the Sub works for 90% of the time. Its when listening to loud kicks during recording when i get the most distortion.

Its also interesting that the sub is only turned up slightly more than half way up on the Gain dial. If i go higher up, the sub would distort even earlier!

@ SRS . have you had the chance to look at the distortion mdat files i posted?

I do use it for drums. But have 2 large soundlocks too for iso booths. I have not looked at the mdat files.

Maybe this site helps: https://data-bass.com/