I read that sealed Qtc .5 was the best transient response, many articles say this is the best for classical music, bass clarity.
I once had Eton 11-580 in a commercial ported speaker and I liked the bass sound, very detailed. But I read that sealed Qtc 0.5 is best for music, and ported has not as good transient response as sealed. A couple previous attempts at designing ported bass speakers were not encouraging. I used formulas and bass design apps and the results did not sound as good as commercial ported speakers, more like disco speakers with overbearing punchy bass, and not good detail. Drivers were DeltaLite2512 and TD12H. o I didn't have confidence that free web software can design good sounding musical vented speaker so I decided on sealed.
I saw a good deal on the Etons so I bought them for a 3 way. I built big sealed boxes for them Qtc .5 (3cu ft.) from what I read, EbP is 74 and between 50 and 100 could work sealed or vented.
Now I play them and the sound is not great. It is boomy and loose, not tight and clear, as I expected. Does not sound like good transient response.
Then I read some more. The Etons are Qts .30, that might be too low for sealed?
My question is why does the low Q speaker sound bad in sealed Qtc .5? I was under the illusion that any speaker would have best transient response, best damped, maximum clarity, with Qtc .5. But I am not hearing that.
I am using active crossover and electronic EQ to flatten the FR. I am using low source impedance SS amplifier with low resistance wires direct connected to the speaker, so it is not a electrical damping issue.
My crossover is 150Hz to the 6.5" sealed mid. Other commercial speakers, reflex, dipole, sealed did not have this problem in my room, so it is not room modes.
I experimented with stuffing. Started with 2" pink FG on 3 interior surfaces, boomy. I added 2.5 pounds of polyfill, packed completely full rather tightly. This seemed to reduce the boominess, but it sounded so terrible I couldn't tell much. I removed half of the stuffing, fluffed it up, still doesn't sound natural, it's stuffy and dead. I removed half again, only half the box volume filled with very fluffed up polyfill. that sounds better. The boom still persists, although it is lessened a bit, I think.
Do I need to make a smaller sealed box? Madisound suggests 0.7 cu ft (20 liters) for sealed, but says vented is better. Or should I just forget about sealed box for this driver, and convert the box to vented? I want ultimate clarity for solo piano, tenor vocals, etc. I don't listen too loud and I have enough amp power for EQ.
How do I get the maximum LF clarity from this driver?
Thanks!!
Rich
I once had Eton 11-580 in a commercial ported speaker and I liked the bass sound, very detailed. But I read that sealed Qtc 0.5 is best for music, and ported has not as good transient response as sealed. A couple previous attempts at designing ported bass speakers were not encouraging. I used formulas and bass design apps and the results did not sound as good as commercial ported speakers, more like disco speakers with overbearing punchy bass, and not good detail. Drivers were DeltaLite2512 and TD12H. o I didn't have confidence that free web software can design good sounding musical vented speaker so I decided on sealed.
I saw a good deal on the Etons so I bought them for a 3 way. I built big sealed boxes for them Qtc .5 (3cu ft.) from what I read, EbP is 74 and between 50 and 100 could work sealed or vented.
Now I play them and the sound is not great. It is boomy and loose, not tight and clear, as I expected. Does not sound like good transient response.
Then I read some more. The Etons are Qts .30, that might be too low for sealed?
My question is why does the low Q speaker sound bad in sealed Qtc .5? I was under the illusion that any speaker would have best transient response, best damped, maximum clarity, with Qtc .5. But I am not hearing that.
I am using active crossover and electronic EQ to flatten the FR. I am using low source impedance SS amplifier with low resistance wires direct connected to the speaker, so it is not a electrical damping issue.
My crossover is 150Hz to the 6.5" sealed mid. Other commercial speakers, reflex, dipole, sealed did not have this problem in my room, so it is not room modes.
I experimented with stuffing. Started with 2" pink FG on 3 interior surfaces, boomy. I added 2.5 pounds of polyfill, packed completely full rather tightly. This seemed to reduce the boominess, but it sounded so terrible I couldn't tell much. I removed half of the stuffing, fluffed it up, still doesn't sound natural, it's stuffy and dead. I removed half again, only half the box volume filled with very fluffed up polyfill. that sounds better. The boom still persists, although it is lessened a bit, I think.
Do I need to make a smaller sealed box? Madisound suggests 0.7 cu ft (20 liters) for sealed, but says vented is better. Or should I just forget about sealed box for this driver, and convert the box to vented? I want ultimate clarity for solo piano, tenor vocals, etc. I don't listen too loud and I have enough amp power for EQ.
How do I get the maximum LF clarity from this driver?
Thanks!!
Rich
I have Omnimic, WT3 and SPL meter. What parameter can I measure which will quantify what I am hearing?
The box is made of inner 3/4" MDF with outer layer of 3/4" hardwood ply, with Green glue layer between, and lots of corner and cross bracing beams, but not window bracing. I can feel only slight vibration when the speaker is playing loudly, knock test is pretty quiet.
The box is made of inner 3/4" MDF with outer layer of 3/4" hardwood ply, with Green glue layer between, and lots of corner and cross bracing beams, but not window bracing. I can feel only slight vibration when the speaker is playing loudly, knock test is pretty quiet.
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Whatever theory of Qtc=0,5 says, it's crap.
I don't find thin sounding (fast transient = pressure not high enough)
speakers pleasing, never have and never will.
For optimal results you should measure TS parameters yourself,
work with them in a box simulation program to see how low
you would like to have it and what box size is acceptable.
My philosophy has always been to use the maximum a driver
can offer. In the end this means bigger boxes with F3/F6/F10
as low as possible.
Deltalite of yours has nothing to do in sealed boxes, according to
manufacturers parameters.
I don't find thin sounding (fast transient = pressure not high enough)
speakers pleasing, never have and never will.
For optimal results you should measure TS parameters yourself,
work with them in a box simulation program to see how low
you would like to have it and what box size is acceptable.
My philosophy has always been to use the maximum a driver
can offer. In the end this means bigger boxes with F3/F6/F10
as low as possible.
Deltalite of yours has nothing to do in sealed boxes, according to
manufacturers parameters.
If you are using EQ to flatten (boost) the response then you are undoing the advantage of the low Q. It's probably this that is causing the boomy sound. I reckon you are having to EQ quite a bit because if you don't the bass is really thin and shallow? Well that's the problem with sealed low Q boxes, early roll off.
Don't believe all you read on the internet, as you have found yourself there are great sounding ported speakers out there. And low Q sealed isn't all it's cracked up to be.
Fortunately as you have made oversized sealed boxes, there may be some scope for adding a port and getting a response without EQ that is more to your taste. Post up the driver specs and box volume and see what people can come up with.
Don't believe all you read on the internet, as you have found yourself there are great sounding ported speakers out there. And low Q sealed isn't all it's cracked up to be.
Fortunately as you have made oversized sealed boxes, there may be some scope for adding a port and getting a response without EQ that is more to your taste. Post up the driver specs and box volume and see what people can come up with.
The room itself is the dominant factor in the bass response of your speaker. Peaks and dips there will be orders of magnitude greater than the peaks and dips of your speaker, no matter what the configuration.
So how does your speaker sound outdoor, where room effects are zero?
Maybe give us some measurements of your speaker.
Measure really close to the woofer and measure at the listening position. What are the differences?
So how does your speaker sound outdoor, where room effects are zero?
Maybe give us some measurements of your speaker.
Measure really close to the woofer and measure at the listening position. What are the differences?
Hi Rich and happy new year.
There are loads of general rubish rules out there that don't apply to the real world. One thing is whatever Qts/Qtc to use. We can simply not speak of bass reproduction without including the room into the equation. A proper designed BR may very well be preferred over sealed one for your application, while for others it may be the opposite.
What you have made is a pretty predictable cabinet design for measurement and for optimizing towards your final design. You know the net cabinet volume and you know the driver parameters. Since I do not have a clue what your in-room response is, it comes in convenient that you are able to measure the response.
I take for granted that you are not using any DSP, but plain passive crossover design, maybe with separate amp for the bass. If however you are using DSP, tuning the response would be obvious.
My suggestion would be to measure the bass frequency response in sweet spot and by e.g. four-six other points around sweet spot within a range of +/- two feet from sweet spot. Then you can average the measured responses to get an image of how the bass is perceived in the listening position.
Complete by doing a separate near-field measurement with the mic as close as possible to he dust cap.
Based on your known design and now, your known responses, it would be easier to give you hint on how to proceed revising your bass system.
Cheers
Edit: I also presume that you have positioned your woofer to the best location
There are loads of general rubish rules out there that don't apply to the real world. One thing is whatever Qts/Qtc to use. We can simply not speak of bass reproduction without including the room into the equation. A proper designed BR may very well be preferred over sealed one for your application, while for others it may be the opposite.
What you have made is a pretty predictable cabinet design for measurement and for optimizing towards your final design. You know the net cabinet volume and you know the driver parameters. Since I do not have a clue what your in-room response is, it comes in convenient that you are able to measure the response.
I take for granted that you are not using any DSP, but plain passive crossover design, maybe with separate amp for the bass. If however you are using DSP, tuning the response would be obvious.
My suggestion would be to measure the bass frequency response in sweet spot and by e.g. four-six other points around sweet spot within a range of +/- two feet from sweet spot. Then you can average the measured responses to get an image of how the bass is perceived in the listening position.
Complete by doing a separate near-field measurement with the mic as close as possible to he dust cap.
Based on your known design and now, your known responses, it would be easier to give you hint on how to proceed revising your bass system.
Cheers
Edit: I also presume that you have positioned your woofer to the best location
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I started modifying a big PA speaker a few years ago and during my researching, a few Members that I trusted advised aiming for a Q quite a bit lower than the normal Butterworth type response.
It was suggested going as low as Q=0.5 ( Bessel is just a little bit above 0.5).
I tuned my B950 to have a roll off curve that resembled a Q of around 0.55, before the vented loading then made it tumble towards the 3pole roll-off inherent to the vented design.
Listening to it is a pleasure. No bass hump. Goes very deep. No exaggeration of voice. Reproduces film sound effects well.
No regrets.
I'm going to look at modifying my Leopards to match the same roll-off, as I repair each one. (surrounds torn due to excessive PA duty).
It was suggested going as low as Q=0.5 ( Bessel is just a little bit above 0.5).
I tuned my B950 to have a roll off curve that resembled a Q of around 0.55, before the vented loading then made it tumble towards the 3pole roll-off inherent to the vented design.
Listening to it is a pleasure. No bass hump. Goes very deep. No exaggeration of voice. Reproduces film sound effects well.
No regrets.
I'm going to look at modifying my Leopards to match the same roll-off, as I repair each one. (surrounds torn due to excessive PA duty).
AndewT; First of all I am glad you hit the nail and are satisfied with your system.
But your experience really can't be used as a general design guide, nor fasit to Richidoo without knowing his environment (not to be rude).
Just to illustrate; In my current setup I use sealed cabinets with almost exact the same Q as yours. With some limitations the 4 pcs. 18" woofers is carefully located by measurements to achieve the most even response with as few peaks and dips as possible at listening position. Still the uncorrected system shows a 16dB linear falling response from 125z to 22Hz. Below 22Hz the response raises. If I would implement a 6dB boost at 20Hz linear rising from e.g. 150Hz, it would imply a 22dB boost to achieve the target. Close to the backwall however the compensation needed is limited to 6-8dB. In my case I would be better off with huge BR tuned ruler flat to the sub octaves.
Fortunately I was aware of this room issue prior to making the cabs.
Like CLS mentioned, he gave up and went OB. He does not say that this is the medicine to cure all pain, but it might seem like dipole/cardiode sometime can be easier to integrate. This is also the case in my living room. I've tested a small U-baffel with great results. Therefore I will also switch to a cabinet free system. But it very soon becomes expensive when sacrificing on capacity is not an option.
But your experience really can't be used as a general design guide, nor fasit to Richidoo without knowing his environment (not to be rude).
Just to illustrate; In my current setup I use sealed cabinets with almost exact the same Q as yours. With some limitations the 4 pcs. 18" woofers is carefully located by measurements to achieve the most even response with as few peaks and dips as possible at listening position. Still the uncorrected system shows a 16dB linear falling response from 125z to 22Hz. Below 22Hz the response raises. If I would implement a 6dB boost at 20Hz linear rising from e.g. 150Hz, it would imply a 22dB boost to achieve the target. Close to the backwall however the compensation needed is limited to 6-8dB. In my case I would be better off with huge BR tuned ruler flat to the sub octaves.
Fortunately I was aware of this room issue prior to making the cabs.
Like CLS mentioned, he gave up and went OB. He does not say that this is the medicine to cure all pain, but it might seem like dipole/cardiode sometime can be easier to integrate. This is also the case in my living room. I've tested a small U-baffel with great results. Therefore I will also switch to a cabinet free system. But it very soon becomes expensive when sacrificing on capacity is not an option.
I think the standard thinking regarding sound quality vs. woofer Q is vastly overstated.
At KEF we had a precision equalizer that could take any second order system (closed box woofer) and dial in a correction to its particulars Fs and Q and replace them with any desired Fs and Q. This was a precursor to the KEF Kube and is often referred to now as the Linkwitz transform.
I started with an assumption that bass character would change greatly as a given Q was varied. You know, "boomy" when Q is high and "tight" when Q is low. I think I varied over the range of Q of .5 to Q of 1.5 to 2. Certainly over that range it sounded more like a simple bass control. Instruments or parts of instruments in the vicinity of fs went up and down in level as Q was varied. Beyond that there was no great change in bass character.
Anyone who is voicing an opinion based on building a system of a given Q and then placing it arbitrarily in their room is "generalizing from the particular". Bass level changes with Q but the character change, at least over a modest range of Q, isn't great and can be swamped by room acoustics.
David S,
At KEF we had a precision equalizer that could take any second order system (closed box woofer) and dial in a correction to its particulars Fs and Q and replace them with any desired Fs and Q. This was a precursor to the KEF Kube and is often referred to now as the Linkwitz transform.
I started with an assumption that bass character would change greatly as a given Q was varied. You know, "boomy" when Q is high and "tight" when Q is low. I think I varied over the range of Q of .5 to Q of 1.5 to 2. Certainly over that range it sounded more like a simple bass control. Instruments or parts of instruments in the vicinity of fs went up and down in level as Q was varied. Beyond that there was no great change in bass character.
Anyone who is voicing an opinion based on building a system of a given Q and then placing it arbitrarily in their room is "generalizing from the particular". Bass level changes with Q but the character change, at least over a modest range of Q, isn't great and can be swamped by room acoustics.
David S,
I'll start by seconding what Dave said above. The room dominates, period. If you want to be able to get even bass, I suggest that you build multiple subs (e.g. four or more) and experiment with placement. Even better (if you only have one listening location) is to put one sub as close to your listening location as possible, meaning under your chair or directly behind the back of your chair - this puts you in the nearfield and the direct response of the sub now dominates over the room response. Then you can focus on designing the subwoofer itself.
On a related topic to Q of speaker, a Q=0.5 speaker is on paper best in terms of transient response, etc. The problem I find is that it is difficult to find a driver that, unequalized, provides a low enough Fc when Qtc is 0.5. As a result, bass is "thin" because the response rolls off early.
Thanks for all the thoughtful response! It is nice to know help is available.
richieboy00 - yes I am using boost, but only about +3dB of baffle step correction low shelf filter at 400Hz. That would be needed in any speaker, so I guess it is not considered boost, per se. I am satisfied with the LF extension of the speaker, just lack of detail is the problem, and how that colors the tone.
Tattoo - I will do some indoor measurements today. I am willing to listen to the speaker outdoors, but it is difficult so i will save that for last resort, since i know other speakers that are not my own design do sound excellent in my room, but they have all been vented, commercial designs. And also Quads sounded VG. Measurements have always shown no significant problems in the room.
Tytte71 - Thanks and HNY to you too! I am using DSP and I can tune the response to whatever I want, but that will not change the transient response? I do have good FR I want now, I have plenty of bass to match midrange. Measurements coming.
CLS - I have built OB speakers before, but again I chose the wrong bass driver for them. Actually I chose the "correct" high Q drivers for OB per internet advice...
but I ended up in same boat as now, poor transient response from too high Q, no bass detail. These were dual AE Dipole12s per side under a Feastrex D5nf. No amount of EQ could help it, both drivers were inappropriate for the design. I learned a lot from that one! I still have that dipole frame, and intend to use it again, but next time either with servo drivers or lower Q drivers with boost.
AndrewT - I hope to find a sound I can enjoy as you have. especially non-exagerrated voices. Hopefully I can do kinda like you have, that is convert my large box sealed to ported with good results. It seems like my driver is intended for large ported box, so my detour into large sealed box may be salvageable.
ScottL - The box internal dimension is 12w x 24h x 18d" = 3cu ft = 85 liter minus bracing and driver volume. Construction is two 3/4 layers, MDF inside, hardwood ply outside, with 1/16" layer of GreenGlue damping goo in between the layers with 100% coverage. The bracing is mostly 3/4" x 1" strips of hardwood ply placed in corner bracing, so that maximum unbraced span is 4" or less. Also a few cross braces of same material from side to side panels. In theory the corner bracing should work well, but I'm not sure it does. I am concerned that box vibration is the problem. But it seems like it is sturdy enough. Knock test is only slightly resonant and damps quickly. I will post some pictures of the bracing. The drivers are mounted to the box using a weather stripping rubber gasket and rubber very small rubber grommets in the screw holes. No direct contact with the box. I will post a picture.
Tytte71 - Dipole is an option, as mentioned above. But other box speakers, like Legacy Focus 2020 with prodigious bass (+6dB EQ) sounded cleaner with 3 bass drivers and ported tuning in the same room position. Also Usher Be20 with 2 of this same bass driver in ported alignment in same room position sounded much cleaner. No acoustic room mode issues with either of these speakers.
Thanks all,
Rich
richieboy00 - yes I am using boost, but only about +3dB of baffle step correction low shelf filter at 400Hz. That would be needed in any speaker, so I guess it is not considered boost, per se. I am satisfied with the LF extension of the speaker, just lack of detail is the problem, and how that colors the tone.
Tattoo - I will do some indoor measurements today. I am willing to listen to the speaker outdoors, but it is difficult so i will save that for last resort, since i know other speakers that are not my own design do sound excellent in my room, but they have all been vented, commercial designs. And also Quads sounded VG. Measurements have always shown no significant problems in the room.
Tytte71 - Thanks and HNY to you too! I am using DSP and I can tune the response to whatever I want, but that will not change the transient response? I do have good FR I want now, I have plenty of bass to match midrange. Measurements coming.
CLS - I have built OB speakers before, but again I chose the wrong bass driver for them. Actually I chose the "correct" high Q drivers for OB per internet advice...
but I ended up in same boat as now, poor transient response from too high Q, no bass detail. These were dual AE Dipole12s per side under a Feastrex D5nf. No amount of EQ could help it, both drivers were inappropriate for the design. I learned a lot from that one! I still have that dipole frame, and intend to use it again, but next time either with servo drivers or lower Q drivers with boost.AndrewT - I hope to find a sound I can enjoy as you have. especially non-exagerrated voices. Hopefully I can do kinda like you have, that is convert my large box sealed to ported with good results. It seems like my driver is intended for large ported box, so my detour into large sealed box may be salvageable.
ScottL - The box internal dimension is 12w x 24h x 18d" = 3cu ft = 85 liter minus bracing and driver volume. Construction is two 3/4 layers, MDF inside, hardwood ply outside, with 1/16" layer of GreenGlue damping goo in between the layers with 100% coverage. The bracing is mostly 3/4" x 1" strips of hardwood ply placed in corner bracing, so that maximum unbraced span is 4" or less. Also a few cross braces of same material from side to side panels. In theory the corner bracing should work well, but I'm not sure it does. I am concerned that box vibration is the problem. But it seems like it is sturdy enough. Knock test is only slightly resonant and damps quickly. I will post some pictures of the bracing. The drivers are mounted to the box using a weather stripping rubber gasket and rubber very small rubber grommets in the screw holes. No direct contact with the box. I will post a picture.
Tytte71 - Dipole is an option, as mentioned above. But other box speakers, like Legacy Focus 2020 with prodigious bass (+6dB EQ) sounded cleaner with 3 bass drivers and ported tuning in the same room position. Also Usher Be20 with 2 of this same bass driver in ported alignment in same room position sounded much cleaner. No acoustic room mode issues with either of these speakers.
Thanks all,
Rich
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Using DSP changes the picture. I do not believe you have done anything wrong with the cabinet alignment. At least I would not hesitate to replicate it. It even looks very nice and rigid 
You might have a capacity issue though. Your woofers can deliver each ~92,5dB@30Hz anechoic with ~12W in before reaching xmax. With proper music material you are limited to ~72dB mean SPL before getting into compression/non-linear issues. In this context it could be an idea to switch to BR as you would gain some 6dB and increase power handling with a few Watt. The woofer impulse response can be made very nice. Group Delay problems will be barely audible as the tuning can be made in the 20Hz area. And anyway, the room will most probably be the dominant factor.
You say that measurements have shown no significant problems in the room. If this is correct, and I hardly believe you, then you're remaining work is IMO limited to calibrating and tuning the response properly.
I would still recommend doing the measurement I mentioned earlier. In addition It would be nice to see GroupDelay and CSD measurement for identifying any areas, if any, to study.
A FR measurement showing the complete speaker can also reveal some issues.
For our info; can you show a dimensional sketch (hxwxl) of your room with distances between speakers, speakers to side/front walls and distance to listening position?
You might have a capacity issue though. Your woofers can deliver each ~92,5dB@30Hz anechoic with ~12W in before reaching xmax. With proper music material you are limited to ~72dB mean SPL before getting into compression/non-linear issues. In this context it could be an idea to switch to BR as you would gain some 6dB and increase power handling with a few Watt. The woofer impulse response can be made very nice. Group Delay problems will be barely audible as the tuning can be made in the 20Hz area. And anyway, the room will most probably be the dominant factor.
You say that measurements have shown no significant problems in the room. If this is correct, and I hardly believe you
, then you're remaining work is IMO limited to calibrating and tuning the response properly.I would still recommend doing the measurement I mentioned earlier. In addition It would be nice to see GroupDelay and CSD measurement for identifying any areas, if any, to study.
A FR measurement showing the complete speaker can also reveal some issues.
For our info; can you show a dimensional sketch (hxwxl) of your room with distances between speakers, speakers to side/front walls and distance to listening position?
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Thanks Charlie and dave for your comments since I last posted.
Tytte71, you are keeping me busy today! I just got this OmniMic measuring system so this is forcing me to learn to use it, but I am 
I see your point about power handling. This is not a dance thumper speaker. The closer I get to Xmax will increase distortion and limit feeling of dynamics. Since this is only a 11" I was intending to eventually add multiple subs below localization freq. I believe along with CharlieLaub that ideal sub placement is very close to listening position. Then the sub volume can be set very low to reduce distortion, increase dynamic range, reduce room mode issues. But that is 50Hz and below, so somebody needs to play mid bass. My Satori 6.5 can play very low, but the dynamics and tone quality cry for help. It sounds best crossing with the Eton at 150 in my room. If I can clean up the Eton sound I might take it even little higher. That is one of the reasons I chose it, it can play much higher cleanly than other large woofers I've tried. In Usher is crosses 2nd order at 640Hz! And I could hear no flaw in my hardest midrange test tracks, but my ears have improved since then. It is a good all around mid bass driver when used properly.
This Eton's low Qts .30 and low Fs 23Hz allow box tuning in mid twenties. This is what Usher Be10 does, using this driver.
Graphs taken from hifi-world review here.
Link to driver specsheet containing TS parameters.
Attached is listening position average 4 sweeps taken at center (LP), up 2 feet, left 2 feet, right 2 feet. Full range speaker. It is active amp, and the levels are only set by ear, so ignore the full range FR downslope. I am constantly adjusting bass volume to compensate for the boominess.
Also attached FR with mic 1/2" from the dustcap, only the woofer is playing. $64,000 question: Why is it not flat?
The woofer is centered 20" above the floor. Distance to listening position is 123", ear height is 41", so the floor bounce cancellation is 540Hz. I designed the box so it could be inverted to put woofer closer to the floor to reduce floor cancellation if needed. But it seems to not be a problem according to the measurements?
Of course my room is not perfect acoustics, there are always some minor bumps in FR. But it is very large, 26 x 42 x 9. It is stick/drywall/vinyl siding on a 5 foot tall dirt crawlspace so low bass just goes right through the walls to the outside. On these sweeps I am seeing worse FR than previous measurements with other speakers, iirc.
I will try to find the floor plan. I'm not sure I can do GD measurement with Omnimic. I will check if it can do it. What is CSD?
Tytte71, you are keeping me busy today!
I just got this OmniMic measuring system so this is forcing me to learn to use it, but I am I see your point about power handling. This is not a dance thumper speaker. The closer I get to Xmax will increase distortion and limit feeling of dynamics. Since this is only a 11" I was intending to eventually add multiple subs below localization freq. I believe along with CharlieLaub that ideal sub placement is very close to listening position. Then the sub volume can be set very low to reduce distortion, increase dynamic range, reduce room mode issues. But that is 50Hz and below, so somebody needs to play mid bass. My Satori 6.5 can play very low, but the dynamics and tone quality cry for help. It sounds best crossing with the Eton at 150 in my room. If I can clean up the Eton sound I might take it even little higher. That is one of the reasons I chose it, it can play much higher cleanly than other large woofers I've tried. In Usher is crosses 2nd order at 640Hz! And I could hear no flaw in my hardest midrange test tracks, but my ears have improved since then.
It is a good all around mid bass driver when used properly.This Eton's low Qts .30 and low Fs 23Hz allow box tuning in mid twenties. This is what Usher Be10 does, using this driver.
Graphs taken from hifi-world review here.
Link to driver specsheet containing TS parameters.
Attached is listening position average 4 sweeps taken at center (LP), up 2 feet, left 2 feet, right 2 feet. Full range speaker. It is active amp, and the levels are only set by ear, so ignore the full range FR downslope. I am constantly adjusting bass volume to compensate for the boominess.
Also attached FR with mic 1/2" from the dustcap, only the woofer is playing.
$64,000 question: Why is it not flat?The woofer is centered 20" above the floor. Distance to listening position is 123", ear height is 41", so the floor bounce cancellation is 540Hz. I designed the box so it could be inverted to put woofer closer to the floor to reduce floor cancellation if needed. But it seems to not be a problem according to the measurements?
Of course my room is not perfect acoustics, there are always some minor bumps in FR. But it is very large, 26 x 42 x 9. It is stick/drywall/vinyl siding on a 5 foot tall dirt crawlspace so low bass just goes right through the walls to the outside. On these sweeps I am seeing worse FR than previous measurements with other speakers, iirc.
I will try to find the floor plan. I'm not sure I can do GD measurement with Omnimic. I will check if it can do it. What is CSD?
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Attached floorplan. Basically one big space with large doorways connecting all areas. It is mostly hard surfaces everywhere except the immediate listening area, so I have added a thin folding sound deadening wall and door between listening area and kitchen. It is only 2" OC703, so it does not affect bass very much. The tray ceiling in the listening area has 4" binary amplitude diffusion covering most of it, along with large binary amplitude diffusor on front wall between speakers. No specific bass traps. I have tried but the room usually sounds better without them.
I'm just happy I can contribute positively to your health by letting you run back and forth in your living room
I honestly believe you can achieve a pretty nice result with your system as is. It will cost you a few calories but it is money cheap.
Your 64000USD question: Could the near field roll-off be due to a LP-filter being active? ehhh... crap, you changed the measurement picture while I was writing - robbing me for modest 64 grands
Near field measurement look pretty good.
Should have asked you earlier but I have taken for granted that you use stereo bass?
Looking at the total system power response and assuming stereo bass (one channel measured) you have some EQ-ing and level matching to do. Changing speaker- and listening position can even out the response (relatively broad band dips at ~55 and ~85 and the peak at ~48Hz). But there is more going on looking at 300 Hz down. Are you 100% sure that XO is set at 150Hz?
The most difficult part here is remote controlling you and based on your feedback, trying to imagine how things sounds
Here is how I would go forward:
1. Isolate the woofers, run them mono with no filter from 10 Hz to at least 1 octave above crossover frequency and take measurements.
2. Try relocate the woofers/speakers and/or listening position while re-measuring until the most even bass response i achieved. Within your wife's acceptable furnituring code off course.
3. EQ the woofers. Gentle attenuation of peaks (widest possible Q and minimum gain). Be very careful trying to amplify dips...avoid as far as possible. Simply don't overdo it just to achieve ruler flat response.
4. Make sure that the woofers are time aligned with the mid/tweeter system
5. Level match to the rest of the speakers.
6. Set XO
7. Remeasure and if satisfied with the measuring result, use your time with music material and your ears to fine tune EQ's, XO and levels.
A simple approach to get closer to a good response with slam. It is some time consuming but suddenly worth the effort.
CSD is Cumulative Spectral Decay (Waterfall)
Regarding the room, my intention was to do a simple simulation. But the room geometry is too complex to get a meaningless result with the REW room simulator.
I honestly believe you can achieve a pretty nice result with your system as is. It will cost you a few calories but it is money cheap.
Your 64000USD question: Could the near field roll-off be due to a LP-filter being active? ehhh... crap, you changed the measurement picture while I was writing - robbing me for modest 64 grands
Near field measurement look pretty good.
Should have asked you earlier but I have taken for granted that you use stereo bass?
Looking at the total system power response and assuming stereo bass (one channel measured) you have some EQ-ing and level matching to do. Changing speaker- and listening position can even out the response (relatively broad band dips at ~55 and ~85 and the peak at ~48Hz). But there is more going on looking at 300 Hz down. Are you 100% sure that XO is set at 150Hz?
The most difficult part here is remote controlling you and based on your feedback, trying to imagine how things sounds
Here is how I would go forward:
1. Isolate the woofers, run them mono with no filter from 10 Hz to at least 1 octave above crossover frequency and take measurements.
2. Try relocate the woofers/speakers and/or listening position while re-measuring until the most even bass response i achieved. Within your wife's acceptable furnituring code off course.
3. EQ the woofers. Gentle attenuation of peaks (widest possible Q and minimum gain). Be very careful trying to amplify dips...avoid as far as possible. Simply don't overdo it just to achieve ruler flat response.
4. Make sure that the woofers are time aligned with the mid/tweeter system
5. Level match to the rest of the speakers.
6. Set XO
7. Remeasure and if satisfied with the measuring result, use your time with music material and your ears to fine tune EQ's, XO and levels.
A simple approach to get closer to a good response with slam. It is some time consuming but suddenly worth the effort.
CSD is Cumulative Spectral Decay (Waterfall)
Regarding the room, my intention was to do a simple simulation. But the room geometry is too complex to get a meaningless result with the REW room simulator.
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Thanks for the help Tytte71.
Sorry, I thought the woofer sweep with LP was useless so I deleted it.
Yes, stereo bass cabinets. Pic attached. Kairos are on top.
The room measurements I posted so far are taken with both speakers playing, measured from listening position. I will post left and right separate in a moment.
Yes, positive that 150Hz low pass is normally in effect for mid and bass drivers. I use JRiver DSP for crossover filters. The deleted plot of woofer closeup with LP filter applied did show the crossover at 150Hz. I'll post it again.
I have done speaker positioning in the past by ear. I can use omnimic to help do that now. I have not fine tuned the speaker position yet.
I'll try your suggestions. Thanks!
Rich
Sorry, I thought the woofer sweep with LP was useless so I deleted it.
Yes, stereo bass cabinets. Pic attached. Kairos are on top.
The room measurements I posted so far are taken with both speakers playing, measured from listening position. I will post left and right separate in a moment.
Yes, positive that 150Hz low pass is normally in effect for mid and bass drivers. I use JRiver DSP for crossover filters. The deleted plot of woofer closeup with LP filter applied did show the crossover at 150Hz. I'll post it again.
I have done speaker positioning in the past by ear. I can use omnimic to help do that now. I have not fine tuned the speaker position yet.
I'll try your suggestions. Thanks!
Rich
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