Dry bass

[Keith_W]

You should post uncorrected response of each channel with either 1/24 or 1/12 smoothing and with a resolution on the Y axis with 5 dB. And waterfall of both channels from 15 Hz to 400 Hz. You could also measure at stomach and feet height and post the waterfall of this. All uncorrected.

All right, this is the UNCORRECTED response of the entire speaker. Bear in mind this is a 3 way active speaker with 2 subwoofers, i.e. 4 channels per side. The reason it looks so lumpy with huge discrepancies between the drivers is because there is no levelling, no room correction, nothing. If you want individual driver measurements, I can provide those as well. Just ask

And this is the waterfall that you requested. Again, uncorrected.

And here it is with all corrections. Note that all the huge dips seen in the Acourate plot are missing. This is probably because with Acourate, I apply a FDW (freq dependent window) only to smooth it, I don't know how to replicate REW's 1/12 smoothing in Acourate. The reason the bass is a tiny bit more lumpy than Acourate's is because the Acourate measurement was taken without moving the mic after performing the initial sweeps for input. These REW plots were taken on another date.

And here is the waterfall, with corrections. Note that I didn't calibrate the microphone to the SPL meter, which is why the noise floor is so high (70dB) and the measurement peak is at "130dB". It is not, if it really was 130dB I would have fled the house. I have provided a generous 1000ms window so you can see how long the fingers are.

And here is the spectro for good measure:

All measurements were taken with a microphone tripod at the main listening position.

@mcdn I can't do a MMM right now, because my interface has been lent to a friend. When I get it back, I will do the MMM. I rummaged through my collection of old REW plots and I can't find my MMM because it is buried like the proverbial needle in a haystack. I found dozens of .mdat's and it's there somewhere, if I happen to find it I will post it. I should have labelled those sweeps properly!

@ppataki I managed to try the settings you recommended for the Pultec EQ. This has gone a LONG WAY towards improving the bass. I found that setting the bass freq too high (80Hz) resulted in overwhelming, bloated bass. I have set it at 30Hz, Boost 3dB, Cut 3dB. This way the effect is subtle. I will work on fine tuning the settings the rest of the evening. If I like the effect, I will bake it into the target curve.

 

[Tangband]

We dont now If the main speaker you have is having good implemented dsp crossovers - it takes nearfield measurements on only one speaker at a time, measuring individual drivers. You cant use school book dsp crossovers because a real loudspeaker have very irregular frequency response. You have to measure everything nearfield and it will take months to optimise the main speakers.

Maybe you have already done that - If that the case its much easier to help. If its not optimised, a lot of dynamic and impact of the sound will be lost with drivers playing slightly out of phase at the crossover frequencies.

Further - Measurements from the listening position are only valid below about 300 Hz. You cant correct anything above that frequency with good results. You have to do nearfield or 1 meter mesurements on one speaker at a time to correct frequencies between 300 Hz - 20000 Hz .

 

[mcdn]

@mcdn I can't do a MMM right now, because my interface has been lent to a friend. When I get it back, I will do the MMM. I rummaged through my collection of old REW plots and I can't find my MMM because it is buried like the proverbial needle in a haystack. I found dozens of .mdat's and it's there somewhere, if I happen to find it I will post it. I should have labelled those sweeps properly!

Great stuff! Looking forward to that MMM. Why do you need an audio interface? Surely just UMIK to USB on your computer?

That 15dB hole at 80Hz looks suspicious to me though - with 4 sources playing (both mains and both subs) that really shouldn’t be there.

 

[tinnitus]

@Keith_W why is your step response so bad? Do you have such great reflexions? And what means ...verify1 at your pulses?

 

[Bjorn]

All right, this is the UNCORRECTED response of the entire speaker. Bear in mind this is a 3 way active speaker with 2 subwoofers, i.e. 4 channels per side. The reason it looks so lumpy with huge discrepancies between the drivers is because there is no levelling, no room correction, nothing. If you want individual driver measurements, I can provide those as well. Just ask

View attachment 333295

And this is the waterfall that you requested. Again, uncorrected.

View attachment 333296

And here it is with all corrections. Note that all the huge dips seen in the Acourate plot are missing. This is probably because with Acourate, I apply a FDW (freq dependent window) only to smooth it, I don't know how to replicate REW's 1/12 smoothing in Acourate. The reason the bass is a tiny bit more lumpy than Acourate's is because the Acourate measurement was taken without moving the mic after performing the initial sweeps for input. These REW plots were taken on another date.

View attachment 333297

And here is the waterfall, with corrections. Note that I didn't calibrate the microphone to the SPL meter, which is why the noise floor is so high (70dB) and the measurement peak is at "130dB". It is not, if it really was 130dB I would have fled the house. I have provided a generous 1000ms window so you can see how long the fingers are.

View attachment 333298

And here is the spectro for good measure:

View attachment 333299

All measurements were taken with a microphone tripod at the main listening position.

@mcdn I can't do a MMM right now, because my interface has been lent to a friend. When I get it back, I will do the MMM. I rummaged through my collection of old REW plots and I can't find my MMM because it is buried like the proverbial needle in a haystack. I found dozens of .mdat's and it's there somewhere, if I happen to find it I will post it. I should have labelled those sweeps properly!

@ppataki I managed to try the settings you recommended for the Pultec EQ. This has gone a LONG WAY towards improving the bass. I found that setting the bass freq too high (80Hz) resulted in overwhelming, bloated bass. I have set it at 30Hz, Boost 3dB, Cut 3dB. This way the effect is subtle. I will work on fine tuning the settings the rest of the evening. If I like the effect, I will bake it into the target curve.

Thanks. Other than some dips from mainly the right speaker in the midbass, the response is overall good. But the level between approximately 110 Hz and 270 Hz is somewhat low. I would ad some shelving here and I would also reduce the raise below 100 Hz some. This should make the midbass and upper bass more prominent. You can experiment with the level here.

As mentioned before, the waterfall shows a fairly high amount of resonances. But I don't know whether you can treat this or not. The thickest Broadsorbor is a great product for this range. You can also measure both channels together at stomach and feet height and post the waterfall of these.

P.S. I haven't checked whether the subwoofers are time aligned, etc. But I assuming you have control over that part. Obviously the speakers and bass drivers also matters.

 

[Sokel]

I don't think applying -20db correction from 400 to 4000Hz is a good idea.
The drop of SNR alone in the dsp unit plus the advice of Dr Toole not to touch anything above transition unless we have anechoic data and even then with a very light hand makes it somehow....

I think it would be far better to put a nice big resistor at the mid and be done with it.

 

[Deleted member 48726]

All right, this is the UNCORRECTED response of the entire speaker. Bear in mind this is a 3 way active speaker with 2 subwoofers, i.e. 4 channels per side. The reason it looks so lumpy with huge discrepancies between the drivers is because there is no levelling, no room correction, nothing. If you want individual driver measurements, I can provide those as well. Just ask

View attachment 333295

And this is the waterfall that you requested. Again, uncorrected.

View attachment 333296

And here it is with all corrections. Note that all the huge dips seen in the Acourate plot are missing. This is probably because with Acourate, I apply a FDW (freq dependent window) only to smooth it, I don't know how to replicate REW's 1/12 smoothing in Acourate. The reason the bass is a tiny bit more lumpy than Acourate's is because the Acourate measurement was taken without moving the mic after performing the initial sweeps for input. These REW plots were taken on another date.

View attachment 333297

And here is the waterfall, with corrections. Note that I didn't calibrate the microphone to the SPL meter, which is why the noise floor is so high (70dB) and the measurement peak is at "130dB". It is not, if it really was 130dB I would have fled the house. I have provided a generous 1000ms window so you can see how long the fingers are.

View attachment 333298

And here is the spectro for good measure:

View attachment 333299

All measurements were taken with a microphone tripod at the main listening position.

@mcdn I can't do a MMM right now, because my interface has been lent to a friend. When I get it back, I will do the MMM. I rummaged through my collection of old REW plots and I can't find my MMM because it is buried like the proverbial needle in a haystack. I found dozens of .mdat's and it's there somewhere, if I happen to find it I will post it. I should have labelled those sweeps properly!

@ppataki I managed to try the settings you recommended for the Pultec EQ. This has gone a LONG WAY towards improving the bass. I found that setting the bass freq too high (80Hz) resulted in overwhelming, bloated bass. I have set it at 30Hz, Boost 3dB, Cut 3dB. This way the effect is subtle. I will work on fine tuning the settings the rest of the evening. If I like the effect, I will bake it into the target curve.

I think those look quite alright corrected. Wouldn't be able to say what's wrong from these measurements IR to your "missing" slam honestly..

-How does the distortion graph look?

 

[Geert]

Why am I not surprised to see you seem to have serious dips in the frequency range that I consider important for physical bass?

So your DRC needs to fill this in artificially, while we know filling in dips is a challenge for DRC.

 

[Bjorn]

Why am I not surprised to see you seem to have serious dips in the frequency range that I consider important for physical bass?

View attachment 333310

So your DRC needs to fill this in artificially, while we know filling in dips is a challenge for DRC.

That's the response of the speakers full range. He's using four subwoofers to cover this area.

 

[Deleted member 48726]

Why am I not surprised to see you seem to have serious dips in the frequency range that I consider important for physical bass?

View attachment 333310

So your DRC needs to fill this in artificially, while we know filling in dips is a challenge for DRC.

But the corrected response looks alright, doesn't it?
Would this, in the corrected response measurement, not show up in the distortion graph if there are issues IR to it trying to boost the dips? -Where would one go looking for "boost issues" ?

-Not trying to be contrary. Rather to understand.

 

[Sokel]

That's the response of the speakers full range. He's using four subwoofers to cover this area.

The measurement includes the subs,he writes it clearly,4 channels each speaker.

 

[sigbergaudio]

What do you mean? I have posted several FR curves, phase, impulse, and step response. What do you want to see? The uncorrected response? Something else?

I wrote exactly what I would be interested in seeing in post #24. It is up to you if you want to share of course.

 

[Geert]

That's the response of the speakers full range. He's using four subwoofers to cover this area.

That would explain it, but then I would like to see the sub measurements included.

The measurement includes the subs,he writes it clearly,4 channels each speaker.

That was also my understanding, given that graph 3 goes very low so it seems to include the subs. But now that I zoom in on the first graph I notice there are separate thumbnails on the left for the measurements of the subs. For the OP to clarify.

 

[Deleted member 48726]

This confuses me; what is the actual smoothing on the corrected measurement?

Uncorrected response is 1/12 smoothing.

Corrected response ?

And here it is with all corrections. Note that all the huge dips seen in the Acourate plot are missing. This is probably because with Acourate, I apply a FDW (freq dependent window) only to smooth it, I don't know how to replicate REW's 1/12 smoothing in Acourate. The reason the bass is a tiny bit more lumpy than Acourate's is because the Acourate measurement was taken without moving the mic after performing the initial sweeps for input. These REW plots were taken on another date.

 

[Sokel]

I zoom in on the first graph I notice there are separate thumbnails on the left for the measurements of the subs. For the OP to clarify.

I saw them too but they look a lot similar as the full range.
And I hope it's without subs though,because otherwise the correction we see would need a self like this:

 

[Tangband]

I don't think applying -20db correction from 400 to 4000Hz is a good idea.
The drop of SNR alone in the dsp unit plus the advice of Dr Toole not to touch anything above transition unless we have anechoic data and even then with a very light hand makes it somehow....

I think it would be far better to put a nice big resistor at the mid and be done with it.

Well, one cant correct anything above 300 Hz with the measurement microphone on the listening position . Toole and Amirm is absolutely correct about this. You CAN correct individual drivers above 300 Hz , but this takes nearfield measurements on only one speaker/ driver at a time.

We dont have any data how the OP has done his dsp crossovers - has he done the nessessary nearfield measurements on and off axis on each driver , are the drivers playing in phase for every crossoverpoint or is he just using schoolbook dsp crossovers in the electrical domain ?

If we dont have more facts on this, this thread is not gonna help OP.

 

[sigbergaudio]

All right, this is the UNCORRECTED response of the entire speaker. Bear in mind this is a 3 way active speaker with 2 subwoofers, i.e. 4 channels per side. The reason it looks so lumpy with huge discrepancies between the drivers is because there is no levelling, no room correction, nothing. If you want individual driver measurements, I can provide those as well. Just ask

View attachment 333295

And this is the waterfall that you requested. Again, uncorrected.

View attachment 333296

And here it is with all corrections. Note that all the huge dips seen in the Acourate plot are missing. This is probably because with Acourate, I apply a FDW (freq dependent window) only to smooth it, I don't know how to replicate REW's 1/12 smoothing in Acourate. The reason the bass is a tiny bit more lumpy than Acourate's is because the Acourate measurement was taken without moving the mic after performing the initial sweeps for input. These REW plots were taken on another date.

View attachment 333297

Can you share the 20-200hz version (unsmoothed) of this too? You have a couple of dips below 100hz that you shouldn't really have with four subs, do you have alternative placement options? Also, 100-200hz is like 7dB lower than 20-100hz. Without knowing your room or setup I suspect you're lacking energy from 80-300hz-ish:

Side note (after looking at the before-graph): Sorry if I missed this earlier in the thread, but are these DIY speakers? Are you both tuning the speakers and calibrating to the room as one operation?

 

[Geert]

But the corrected response looks alright, doesn't it?

Yes. But before I go into that I would like to make sure our understanding of the graphs is correct (does the first one include the subs).

 

[Keith_W]

You seem to have some REW measurements based on one of the screenshots. Could you show 20-200hz unsmoothed and 20-20,000hz with 1/6 or 1/12th smoothing of your current response?

Y-axis 45-105dB

You could also consider taking measurements at both head and stomach height and averaging these, sometimes they're quite different in the bass range.

Your wish is my command! This is 20-200Hz unsmoothed.

20-20kHz with 1/12 smoothing has already been posted. Sorry I missed your earlier reply, this thread seems to have generated a lot of interest from a lot of big guns on ASR for some reason. I am really grateful for that, thanks guys!

This confuses me; what is the actual smoothing on the corrected measurement?

Uncorrected response is 1/12 smoothing.

Corrected response ?

All the REW responses have 1/12 smoothing unless indicated otherwise.

@Geert all the full range measurements have subs included. It is not possible to remove the subs and still get a decent measurement. As I indicated earlier, the speakers have been modified with a replacement woofer that is linear between 50-800Hz with very little bass output below 50Hz. This was a deliberate decision, because I knew that I would be removing all sub frequencies from the main speaker.

So it is clearer what we are talking about, this is a sketch of the listening room:

At the bottom of the pic you can see a staircase and a narrow corridor leading to the dining room. At the back of the room you can see a large sliding door leading to the backyard. The listening sofa is positioned 1.5m away from the rear sliding door. The subwoofers were positioned by placing one sub at the MLP and doing sweeps around the room. I selected the positions with the fewest nulls. The main speakers were positioned by ear, where they produced the best stereo image, that's where they went.

All the drivers have individual driver correction (you can see that in the crossover that I posted earlier). Each driver has a reversed all pass filter convolved into the correction to flatten the phase angle. All drivers are time aligned with respect to the tweeter: horns 0.0208ms, woofers 0.312ms, and subs 1.875ms using Acourate's time alignment procedure. Then overall room correction is applied with target curve applied full range. I am aware of the debate of correcting up to Schroder only or full range @Tangband, in fact I used to only correct up to Schroder but I now do it full range. It sounds better, in fact the clarity of the system is pretty astonishing. Veils were lifted, night and day, wife could hear difference from the kitchen, etc. I am not joking, the difference all these corrections make can really be heard from the kitchen!

There is absolutely nothing wrong with the system from 200Hz up, apart from perhaps the polar response but there is nothing I can do about that. Even the bass is pretty good, there are no audible peaks and dips, it sounds tight, and I am almost happy with it. What I would like is more impact and slam, and @ppataki's suggestion of the Pultec EQ has gone a long way towards solving it. It is a few hours now since I started tuning, and I have improved the result audibly. It is still not quite where I would like it, at the moment I CAN get impact and some physicality, but my impression is that it is too low in the freq range, and tuning it higher results in bloated, muddy bass. There is a sweet spot somewhere, and I am going to find it. This post was made while I am in the middle of tuning, so back to tuning I go. I will report if I achieve a satisfactory result.

 

[ppataki]

@ppataki's suggestion of the Pultec EQ has gone a long way towards solving it. It is a few hours now since I started tuning, and I have improved the result audibly. It is still not quite where I would like it, at the moment I CAN get impact and some physicality, but my impression is that it is too low in the freq range, and tuning it higher results in bloated, muddy bass. There is a sweet spot somewhere, and I am going to find it. This post was made while I am in the middle of tuning, so back to tuning I go. I will report if I achieve a satisfactory result.

I am happy that it helped! (it helped me too hence I suggested)
In case you can't find the sweet spot with Pultec EQ, you can also dive into the resonant low shelf topic I mentioned earlier, just one filter to start with - it will give you much wider room to maneuver