Sigberg Audio Manta Cardioid active speakers: Full measurements (Spinorama)

[sigbergaudio]

@sigbergaudio what was the reason for not using digital crossovers in your designs? (you could EQ the on-axis easily too)

All my designs have digital crossovers. The whole point of the last few posts is that EQing on-axis would be a bad idea, because it messes up off-axis response / total energy level in-room.

 

[thewas]

The whole point of the last few posts is that EQing on-axis would be a bad idea, because it messes up off-axis response / total energy level in-room.

Equalising on-axis though is not what Harman research recommends but getting loudspeakers with smooth directivity where having or equalising to a smooth/flat on-axis leads also to a smooth of-axis and sound power. To quote Floyd Toole:

"It is essential to note that this is the room curve that would result from subjectively highly-rated loudspeakers. It is predictable from comprehensive anechoic data (the "early reflections curve in a spinorama). If you measure such a curve in your room, you can take credit for selecting excellent loudspeakers. If not, it is likely that your loudspeakers have frequency response or directivity irregularities. Equalization can address frequency response issues, but cannot fix directivity issues. Consider getting better loudspeakers. Equalizing flawed loudspeakers to match this room curve does not guarantee anything in terms of sound quality."

 

[sigbergaudio]

Equalising on-axis though is not what Harman research recommends but getting loudspeakers with smooth directivity where having or equalising to a smooth/flat on-axis leads also to a smooth of-axis and sound power. To quote Floyd Toole:

"It is essential to note that this is the room curve that would result from subjectively highly-rated loudspeakers. It is predictable from comprehensive anechoic data (the "early reflections curve in a spinorama). If you measure such a curve in your room, you can take credit for selecting excellent loudspeakers. If not, it is likely that your loudspeakers have frequency response or directivity irregularities. Equalization can address frequency response issues, but cannot fix directivity issues. Consider getting better loudspeakers. Equalizing flawed loudspeakers to match this room curve does not guarantee anything in terms of sound quality."

There is no need to quote Toole to me. I don't know what to tell you beyond the fact that these speakers provide a balanced in-room response without EQ (as I have also shown in earlier posts).

I am not claiming the speakers are perfect, I am claiming the preference score is imperfect as an absolute tool to evaluate loudspeaker performance. Our own SBS.1 measures better than Manta according to preference score, but they don't sound better.

 

[kma100]

I think we apply too much weight to the preference score. I view it as a general guide with a large margin of error.

 

[thewas]

There is no need to quote Toole to me. I don't know what to tell you beyond the fact that these speakers provide a balanced in-room response without EQ (as I have also shown in earlier posts).

It would be interesting to compare directly the plots of their in-room response with the PIR or ERC (which are very similar), usually the are very similar above 500 Hz.

I am not claiming the speakers are perfect, I am claiming the preference score is imperfect as an absolute tool to evaluate loudspeaker performance. Our own SBS.1 measures better than Manta according to preference score, but they don't sound better.

Above I didn't refer to your loudspeaker, just the supposed contradiction of equalising the on-axis response.

By the way even for your mentioned comparison I don't see a contradiction to the Harman research and score as we know that the bass has one of the biggest effects in loudspeaker preference, meaning that a loudspeaker, setup, placement and/or EQ which will lead to a smooth and deep bass will be preferred (even to an anechoical linear bass loudspeaker which at the LP has significant peaks or dips).

An interesting comparison would be of both loudspeakers equalised to the same bass response and of course under the usual necessary premises for such (blinded, same level, same/close position etc).

 

[sigbergaudio]

It would be interesting to compare directly the plots of their in-room response with the PIR or ERC (which are very similar), usually the are very similar above 500 Hz.

I posted three different rooms with Mantas in two different posts earlier in the thread, reposting below for convenience. Note that the two at the bottom is apparently only from 500hz and up, I guess I wanted to emphasize this area since the discussion was around the 1-2khz phenomena.

 

[thewas]

Where these single measurements or averages or MMM?
The full REW files are always helpful to analyse such as now not even the legends with the smoothing factors are visible.

 

[sigbergaudio]

Where these single measurements or averages or MMM?
The full REW files are always helpful to analyse such as now not even the legends with the smoothing factors are visible.

If I remember correctly these are averages of single left/right measurements at listening position. Smoothing looks like 1/12.

 

[sigbergaudio]

If I remember correctly these are averages of single left/right measurements at listening position. Smoothing looks like 1/12.

 

[hex168]

I've never understood paying anything beyond cursory attention to on-axis response. It is on a single line and covers zero area.

 

[Blockader]

All my designs have digital crossovers. The whole point of the last few posts is that EQing on-axis would be a bad idea, because it messes up off-axis response / total energy level in-room.

I am not asking this in an antagonistic way: How can EQ'ing the on-axis response mess up the off-axis response for speakers that have controlled directivity? You've read Toole; you know that on-axis sound is perceptually dominant to reflections. What good are accurate reflections if the on-axis sound is wonky? The received information which is dominant over reflections is wonky.

 

[sigbergaudio]

I am not asking this in an antagonistic way: How can EQ'ing the on-axis response mess up the off-axis response for speakers that have controlled directivity? You've read Toole; you know that on-axis sound is perceptually dominant to reflections. What good are accurate reflections if the on-axis sound is wonky? The received information which is dominant over reflections is wonky.

Define wonky. First of all, on-axis is not the listening response, the speaker is designed for limited to zero toe-in.

This is 10 degrees:

The most significant deviation is between 1-2khz, where the dip is around 1.5dB. This is an intended compromise because the speaker is hot off-axis in this area.

While direct sound is predominant, reflections do matter. The speaker has been tuned to balance the two in the best way possible. I can assure you lifting this dip further will not make the speaker sound better.

The total difference between the highest area around 150-200hz (again intentional to give enough energy in this area in-room) and the dip at ~1250hz results in a response of +/-2.15dB.

I would not call it wonky, but I am certainly biased.

 

[goat76]

If this loudspeaker is intended for zero toe-in, wouldn't the response at 30 degrees be the most interesting measurement to look at?

 

[sigbergaudio]

If this loudspeaker is intended for zero toe-in, wouldn't the response at 30 degrees be the most interesting measurement to look at?

I recommend 0-10 degrees toe-in. But that is certainly available, below is 20 and 30.

20 degrees:

30 degrees:

 

[ernestcarl]

Another somewhat interesting find with the Manta and spinorama, is how good the score is with EQ. It looks like the preference score engine basically disagrees with how the speaker is tuned, more than that the inherent qualities are problematic. With EQ it jumps from 6.8 to 8.3 (compared to with just sub).

View attachment 349527


View attachment 349528


The engine suggests lowering the midbass and removing the dip at 1500hz to get the score up to 8.3. Both of these are in my opinion wrong decisions with regards to what sounds most natural in-room, and taking into account the overall dispersion characteristics.

So at least in my opinion, the frequency response giving a 6.8 score sounds better than the one giving 8.3. Something to ponder.

I agree with you that the auto-EQ suggestions to improve the score does not necessarily make a speaker sound better — at least to my ears in my room. I remember when I tried using the EQ suggested for the Fluid FX50 coax (and if I remember correctly) filters by Maiky and Pierre didn’t quite work for me. The one used by Amir himself was actually good, but I didn’t like the additional HF shelving… Focusing on boosting only the preference score does not guarantee good subjective listening results.

 

[mj30250]

I agree with you that the auto-EQ suggestions to improve the score does not necessarily make a speaker sound better — at least to my ears in my room. I remember when I tried using the EQ suggested for the Fluid FX50 coax (and if I remember correctly) filters by Maiky and Pierre didn’t quite work for me. The one used by Amir himself was actually good, but I didn’t like the additional HF shelving… Focusing on boosting only the preference score does not guarantee good subjective listening results.

Personally, whenever I've attempted to EQ above Schroeder something inevitably sounds "off". I'm not sure if it's just some sort of expectation bias or reverse-placebo, but I almost always end up reversing it. The only time I've felt it has worked well (subjectively) is after using MA-1 w/ my Neumann monitors, which applies a full-range correction that you can't defeat beyond going in and setting your own individual filters.

 

[ernestcarl]

Personally, whenever I've attempted to EQ above Schroeder something inevitably sounds "off". I'm not sure if it's just some sort of expectation bias or reverse-placebo, but I almost always end up reversing it. The only time I've felt it has worked well (subjectively) is after using MA-1 w/ my Neumann monitors, which applies a full-range correction that you can't defeat beyond going in and setting your own individual filters.

Well, I only do manual adjustments so it’s easy to make changes if there’s something I really find off about the loaded EQ. When doing quick AB comparisons I try to isolate individual filters (if broad enough) or specific sections (e.g. low-mids and mid-HF xo).

 

[lewdish]

Does the cardioid design improve imaging, it does look like directivity is pretty concentrated. Also wondering but why does it look like it dies off pre-maturely after 12k?

 

[Blockader]

Also wondering but why does it look like it dies off pre-maturely after 12k?

Because the tweeter begins to beam at frequencies above 12 kHz, its power response diminishes significantly at higher frequencies. This results in a noticeable roll-off in the in-room response.
Ideally, the designer should do some modifications to the waveguide or add an acoustic lens to create additional diffractions above 12 kHz and widen the tweeter's beam. Easier said than done.

 

[sigbergaudio]

Does the cardioid design improve imaging, it does look like directivity is pretty concentrated. Also wondering but why does it look like it dies off pre-maturely after 12k?

Does the cardioid design improve imaging:
This is a somewhat difficult question, since I guess imaging is a somewhat difficult concept. I think the imaging characteristics is primarily due to the coaxial driver, but the cardioid configuration increases the feeling of the soundstage being large and immersive.

Premature drop off:
It doesn't die off as such, but the dispersion narrows. The effect of that will vary with the room. Below is one room where the slope is pretty even up to around 18khz where it falls off a bit more. In general it's pretty normal to see speakers drop off harder above 10khz in-room.

Here is the on-axis nearfield indoors, showing 0dB drop up to 17.5khz: