Active monitors with deep low end

[Rasboo]

Hello!
I'm hoping some of you knowledgeable audio scientists might be able to lend a helping hand with selecting a new reference monitor for my measurement setup.
As the title suggests, I'm looking for information about monitors that offer clean deep low end.

I have been mainly looking into 8" monitors as those i have found with 10" woofers are so much more expensive. The issue is that distortion levels generally spike below about 40Hz and I really need accuracy all the way down towards 20Hz.
(Edit: 20Hz is not the be all end all. I "need" to push a bit of air deeper than 35Hz without going up to 50% THD... i should have phrased it differently, or emphasized the "towards" 20Hz i guess)
I understand that this is not practically possible, but maybe i can get some support in finding the best way forward. Any 8" that particularly shines in terms of low distortion at the extremes of the audio spectrum? Any affordable 10" out there that i have missed?
Price range is approximately 1000$

To avoid future questions:
This will be used mainly, if not only, for engineering work involving analyzing single frequencies. So a lot of parameters that are important for music is not an issue this time around. What I need is something that can deliver power with minimal distortion throughout the audible range.

I would use a sub but i really need focused and predictable projection characteristics as well (my old Genelec S30 are a bit too unpredictable in this regard). Measuring microphone directivity is on the agenda..

Note that this is not about monitors having loads of low end straight out of the box. I do automated frequency correction EQ with very high resolution. This is about having the highest possible clean headroom.

Any help is highly appreciated!
Cheers

 

[JSmith]

Hi and welcome to ASR.

I really need accuracy all the way down towards 20Hz

It will be difficult to find that in a monitor/bookshelf with 8" woofers...

You might want to look at these as a potential, but they're not going to go flat down to 20Hz;

Adam T8V Studio Monitor Review

This is a review and detailed measurements of the Adam T8V active monitors (speaker). It was kindly sent to me by the company a few months ago. I was surprised at the very low cost of these speakers at US $299 (each) considering that they are DSP speakers with dual amplification. This is one...

www.audiosciencereview.com

The size of the driver and the cabinet design/size greatly affect low-end response.


JSmith

 

[staticV3]

Price range is approximately 1000$

Per pair?

 

[Purité Audio]

Unfortunately spls and bass extension still cost.
Keith

 

[lowkeyoperations]

To get down anywhere near 20Hz an 8” driver will need to be heavily DSP adjusted. This will increase distortion and reduce SPL output.

You can find the occasional active monitor that will boost the bass at low listening levels and gradually reduce the bass extension as you raise the volume.

But you can’t have low distortion and high SPL from an 8” woofer.

 

[Mnyb]

doubt you get audible 20Hz with an 8" ? even if it can do it cleanly say a closed box speaker with EQ would it do it loud enough ,you may feel it thou ?

the curve i googled may not be entirely correct it may be worse >90 db to actually hear it .

i f you do "hear" 20hz sine test tones its probably the overtones due to the severe distorsion most drivers have with LF .

A closed box dual 15" sub from rhytmic , its has a feedback system on the driver to mitigate distorsion. per channel ? is this stereo ?

 

[Mnyb]

My active kef LS60 actually do clean 20Hz in the extended setting , the 4 bass driver per speaker are equal to roughly 10" , it's there its low distortion , but not loud .

 

[Sokel]

Did a little search for such monitors,the lowest price I found for 20Hz,decent SPL and distortion is probably 30x your price range.

If single tones are your goal better try a clean sub down there,even the modest mains monitors do nice 30s but not 20s.

 

[Matias]

Here is a good place to start:

Ranking table of speaker's measurements

www.spinorama.org

 

[Sokel]

My active kef LS60 actually do clean 20Hz in the extended setting , the 4 bass driver per speaker are equal to roughly 10" , it's there its low distortion , but not loud .

This ones?



They are really good speakers but for the described use,SPL,headroom,low distortion down low it will be unusable.
Even bigger tower would be so,one has to go way big to go there.

 

[sigbergaudio]

Don't forget you will probably get 6-10dB room gain at 20hz with the right placement, so it's slightly easier than it sounds. But probably still not realistic for a moderately priced 8".

 

[Waxx]

Neumann KH150's or Genelec 8331A are seen as some of the best monitors, but none will do 20Hz on decent volume. Aslo the D&D 8C won't do it.

And these are top of the line monitors, for your bduget you surley can't. Use a sub if you want it that low (and even that will be a challenge).

 

[Mnyb]

This ones?

View attachment 393012

They are really good speakers but for the described use,SPL,headroom,low distortion down low it will be unusable.
Even bigger tower would be so,one has to go way big to go there.

yes not loud enough even with two of them ?

i use mine with dual sub's KC92 ( these are probably not up for the task either )

 

[Sokel]

yes not loud enough even with two of them ?

i use mine with dual sub's KC92 ( these are probably not up for the task either )

Things change with subs,a lot.
Erin has measured yours and they seem really good



Don't know if their SPL and distortion are ok for OP though.

 

[Rasboo]

Thank you thank you for the replies!

The Adam 8" that JSmith pointed at is one top contender. But in the end i guess it's just physics and 8" (in this price range at least) are more or less equally up to the task.

The issue with using external subwoofers is that I want to come as close as possible to using a point source as possible.
If i only had bottomless pockets, Genelecs "the one" looks very juicy.

Your replies has pushed me more towards building a custom speaker. SB has this new 9 1/2" textreme driver that has a really low resonant frequency and seems to extent far up in the treble.

 

[Purité Audio]

Bass is never going to be point source.
Keith

 

[darakon]

You know, that 20Hz is not even audible, right?
It will mainly cause vibrations, which make every object in your room shake und cause noise and distortion.

 

[sigbergaudio]

@Rasboo As Keith pointed out (pun intended), an external subwoofer won't ruin the idea of a point source. I am also not sure why a point source is important if the purpose is analysis of single frequencies?

 

[ChrisG]

I just want to highlight this, since a lot of people seem to be missing it:

Measuring microphone directivity is on the agenda.

I'm glad more people are looking at measuring microphones, and directivity is the sort of information that's often sorely lacking.

When it comes to getting decent measurements of mics, the desired sound level is going to be more about the acoustic signal-to-noise ratio: you don't necessarily need a flat response, but you do need whatever is playing to be considerably louder than the background level.
The measurement of mics I've done so far haven't been too concerned about harmonic distortion. I used REW to calibrate for a test speaker that had a 12dB/octave rolloff at 100Hz, and could reliably measure mics down to 30Hz. Below that, the speaker output fell into the acoustic background noise. There was some harmonic distortion in the speaker's output, but since I was only looking at frequency response, this was generally ignored.


In order to make useful recommendations, my question is this: what's the measurement distance?

A small speaker can produce 20Hz quietly, so you'll need to get the mic pretty close to capture it above the background noise. However, a directional mic used up-close will exhibit proximity effect (the EV RE20 and variants avoid this), which will skew your frequency response measurements in a big way.

If you want to measure over 1m away, you're going to need either a very quiet room, or a bigger speaker.


If it was my project, I'd put a 3" coaxial and an 8" long-throw subwoofer driver in a cabinet. Measure 20Hz-200Hz with the 8", and then 100Hz-20kHz with the 3" coaxial. Splice the data in the overlapping octave.

Bass is never going to be point source.
Keith

Keith, slap any sensible-sized driver in a sealed box and you've got point-source bass. Until you get to concert-grade subwoofer arrays, subwoofers are pretty much always a point-source.
Rooms, however, are a different matter. Perhaps this is what you're alluding to.

@Rasboo As Keith pointed out (pun intended), an external subwoofer won't ruin the idea of a point source. I am also not sure why a point source is important if the purpose is analysis of single frequencies?

Rasboo is trying to measure microphone directivity. ie, the angle of the microphone relative to the speaker will be varied, so the sound source needs to be in a single position.


Chris

 

[sigbergaudio]

Rasboo is trying to measure microphone directivity. ie, the angle of the microphone relative to the speaker will be varied, so the sound source needs to be in a single position.

Well, the sound source itself has no directivity at 20hz, but for the sake of argument he could put the speaker on top of the subwoofer, and he would be more than fine. At 20hz one wavelength is 17 meters.