Would that also apply to the port location?
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Sigberg Audio Saranna (fullrange, cardioid active floorstander) development thread
- Thread starter sigbergaudio
- Start date
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- Thread Starter
- #382
The port doesn't really contribute meaningfully to the response above 60hz (it is tuned to 28hz in the current prototype), so it will not matter too much where the port is. Wavelength at 60hz is almost 6 meters, and at the peak of the port output the wavelength is 12 meters. So the response of the port likely won't change much if you move it 34cm (rear vs front).
So in the end the placement of the port is more a visual thing.
OP
- Thread Starter
- #383
Test in a second room. Not as huge a difference as the first room, but still more energy from ~100hz and up. Green is with the bass drivers facing backwards towards the wall.
OP
- Thread Starter
- #384
Saranna is still not stabilized on the drawing board, will likely do another prototype soon. This version is 2cm more narrow (24 vs 26cm wide baffle). I am also contemplating darker wood. This is moving in a somewhat different direction than the initial version, more discreet and elegant. At least until you look at the back. Will probably also skip the open baffle approach to the top chamber.
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- Thread Starter
- #385
Next prototype will likely also introduce a tilt (similar to both SBS.1 and Manta) to reduce diffraction in the coax. Probably 4-5 degrees. Will introduce a plinth/base with adjustable feet to the next prototype so it's easy to experiment with the tilt. Not sure yet if the production model will have that or a fixed, tilted base.
On-axis with no vertical tilt vs 15 degrees off-axis with 4 degrees vertical tilt:
On-axis with no vertical tilt vs 15 degrees off-axis with 4 degrees vertical tilt:
Just for sure, the curves in red and green, which is which condition?
OP
- Thread Starter
- #387
Red is on-axis with no tilt.
Thank you, same as I thought about it!
To be correct, diffraction of the coax is not reduced but the effect of coax diffraction on the 15 degree off-axis frequency response...
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- Thread Starter
- #390
By tilting the coax vertically, there will be less diffraction in the horizontal plane, which is more important than the vertical. So the response will be better both at the reference angle (~15 degrees) but also overall.
OP
- Thread Starter
- #391
Quick update, started on the new prototype, aim to finish this week or next. The finish will still be rough as the previous one, but am looking into alternatives for darker wood veneer for the production speaker.
New dimensions:
250x1070x340mm. So just 10mm more narrow than before.
The bass drivers will be moved to the rear as indicated earlier. Also done some adjustments to cardioid port placement and the coax chamber is no longer open in the back. The coax is 10mm closer to the top, and the cabinet will be tilting backwards (done with platform/feet at the bottom). The internal workings of the bassport also had to change due to the new driver placement, and the outer port diameter has been adjusted slightly.
New dimensions:
250x1070x340mm. So just 10mm more narrow than before.
The bass drivers will be moved to the rear as indicated earlier. Also done some adjustments to cardioid port placement and the coax chamber is no longer open in the back. The coax is 10mm closer to the top, and the cabinet will be tilting backwards (done with platform/feet at the bottom). The internal workings of the bassport also had to change due to the new driver placement, and the outer port diameter has been adjusted slightly.
OP
- Thread Starter
- #392
Disassembled and impatiently awaiting a new enclosure. 
OP
- Thread Starter
- #393
Protoype up and running, not much else to report until a bit into next week probably.
OP
- Thread Starter
- #394
It's been a lot of focus on the visuals lately, but now that the new prototype is up and running, there's so many changes I essentially have to tune it from scratch. That gives us the opportunity to dive into the more technical stuff again.
Today I've done some nearfield measurements of the bass drivers and port. Since there is one common and relatively large chamber for the two bass drivers, the full height of this chamber is relatively long, giving us a resonance not too far from the operating band of the bass drivers. The current crossover is at 140hz, while the resonance is at 230hz. With a combination of cabinet dampening, DSP and the fact that the crossover is quite a bit further down, this resonance is handled pretty well.
Further, we have a port resonance from the bass reflex port, but this is all the way up around 430hz, so it is in practice completely supressed.
The thin green line is nearfield port response, the thick green line is the average of the nearfield output of the port, and each of the two bass drivers.
Today I've done some nearfield measurements of the bass drivers and port. Since there is one common and relatively large chamber for the two bass drivers, the full height of this chamber is relatively long, giving us a resonance not too far from the operating band of the bass drivers. The current crossover is at 140hz, while the resonance is at 230hz. With a combination of cabinet dampening, DSP and the fact that the crossover is quite a bit further down, this resonance is handled pretty well.
Further, we have a port resonance from the bass reflex port, but this is all the way up around 430hz, so it is in practice completely supressed.
The thin green line is nearfield port response, the thick green line is the average of the nearfield output of the port, and each of the two bass drivers.
OP
- Thread Starter
- #395
Left and right channel from the MLP in my main listening room. Rear facing drivers crossed over at 200hz currently. No smoothing, two EQ points below 90hz on each channel.
Average left/right:
Average left/right:
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- Thread Starter
- #396
Controlled directivity and even spread is pretty fascinating. Here is a measurement @15deg from 40cm (orange) overlaid an average of L+R measured at the listening position..
Since this measurement was taken 6-800hz was lifted a bit and the tweeter has increased gain with 1dB.
Since this measurement was taken 6-800hz was lifted a bit and the tweeter has increased gain with 1dB.
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- Thread Starter
- #397
-6dB at 16.5hz in this room. Not sure I can release this speaker, who are going to buy our subwoofers?
OP
- Thread Starter
- #398
And did moving the drivers help with SBIR / cancellations? I'll go with yes, at least in this room that typically has issues around 100-300hz.
Listening position, purple is the previous prototype.
Listening position, purple is the previous prototype.
OP
- Thread Starter
- #399
Manta with two 10D (red) vs current Saranna prototype in the same room. Interestingly I have not actively or intentionally compared them when tuning Saranna.
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- Thread Starter
- #400
What does the barrage of measurements from yesterday tell us?
First of all, remember that this is a development thread, and we just iterated on the cabinet with some pretty significant changes. This means none of the measurements are representative of the final product. There have already been a number of changes based on listening sessions yesterday and today.
Second, many of the measurements are in-room and from a single room (tests will be expanded to additional room in due time), so they are not necessarily representative of what will happen in any given room.
All that being said, we see a response that are well extended in the sub bass, and we also see midbass behaviour that is very promising. In this room the midbass response and energy level (not capacity) is comparable to that of Manta with dual subwoofers.
The overall tonality is also very similar to Manta, which in my book is a very good thing.
What we cannot see from the measurements is how it sounds, and the painstaking exercise of ensuring it sounds good across every genre and track I can think of starts (again) now. It sounds very promising so far. Initially a bit too tidy and restrained yesterday, but it has loosened up after some adjustments. The midbass level has also been dialed back a bit to ensure it doesn't sound bloated on tracks that are busy in this frequency range.
The focus of the redesign was the bass and midbass, but listening through tracks now brings the midrange and tweeter into focus as well. Overall it is very smooth and pleasant to listen to, I'm tempted to say almost "buttery", to use a bit of hifi magazine flower language. The compression driver in this coax is a very positive experience.
More to follow!
First of all, remember that this is a development thread, and we just iterated on the cabinet with some pretty significant changes. This means none of the measurements are representative of the final product. There have already been a number of changes based on listening sessions yesterday and today.
Second, many of the measurements are in-room and from a single room (tests will be expanded to additional room in due time), so they are not necessarily representative of what will happen in any given room.
All that being said, we see a response that are well extended in the sub bass, and we also see midbass behaviour that is very promising. In this room the midbass response and energy level (not capacity) is comparable to that of Manta with dual subwoofers.
The overall tonality is also very similar to Manta, which in my book is a very good thing.
What we cannot see from the measurements is how it sounds, and the painstaking exercise of ensuring it sounds good across every genre and track I can think of starts (again) now. It sounds very promising so far. Initially a bit too tidy and restrained yesterday, but it has loosened up after some adjustments. The midbass level has also been dialed back a bit to ensure it doesn't sound bloated on tracks that are busy in this frequency range.
The focus of the redesign was the bass and midbass, but listening through tracks now brings the midrange and tweeter into focus as well. Overall it is very smooth and pleasant to listen to, I'm tempted to say almost "buttery", to use a bit of hifi magazine flower language.
The compression driver in this coax is a very positive experience. More to follow!
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