Hi Patrick Bateman,
Thanks, GM's modeling obove should convince you further.
Yes the author of that small horn I modeled had in mind corner loading so I used it to.
Pi loading will reveal increasing ripple towards horn cutoff at about 4dB maximum since the horn is somewhat trunkated for that loading, applies to both drivers.
Other parameters such as BL plays on the other hand a major role if horn is trunkated for a given loading, ripple will vary.
Can we agree that regarding horn loading, drivers fs alone is not of significance?
Patrick Bateman said:
Thanks, GM's modeling obove should convince you further.
Yes the author of that small horn I modeled had in mind corner loading so I used it to.
Pi loading will reveal increasing ripple towards horn cutoff at about 4dB maximum since the horn is somewhat trunkated for that loading, applies to both drivers.
Other parameters such as BL plays on the other hand a major role if horn is trunkated for a given loading, ripple will vary.
Can we agree that regarding horn loading, drivers fs alone is not of significance?
Patrick Bateman said:
I'd say that if you had spare attic space above a room you could easily cut a huge hole in the ceiling and have 12 BP's in your house. AndrewT's doing it with a horn so why not?
Patrick Bateman said:
Danley has also recommended EQ'ing the lab in a home environment down to the 15 - 20Hz mark. It's all about the application. I'm still looking for a solution to give me some proper output in the ~10Hz region which I think will be too low for 2 labhorns. Tom D reckoned I'd be ok using 4 of them and EQ'ing flat to 10Hz.
4 labhorns in the home.
At 20Hz 12 shivas is showing around 85 - 90 dB for 1W in winISD, with a group of 4 labhorns showing around 93dB at the mouth. I can't find a plot of 6 labhorns to give a proper answer. I'd guess another few dB with another couple of cabs. I've read that the horns cutoff gradually rolls off, so still has some gain below Fl.
Cheers,
Rob.
"It's only natural to blame the box. Have you ever considered that the box you're sitting in is the problem, and not the box the speaker is in?
When you took the speaker out of the box, you changed the directivity of the speaker. It went from a monopole to a dipole. And guess what Rob's horn and your dipole both had in common? That's right, controlled directivity."
My observations were not based on listening, but on watching the driver. Playing the same piece of music with something like 100 hz material, the driver went from overdamped when mounted in the box to reproducing the music with significantly improved accuracy. I went back and forth between the two and the differences were startling. This expains the much greater transparency and accuracy one notices with open baffle speakers. After this observation, I was sold on speakers "without backs." Incidently, when that subwoofer was functioning correctly (it had a servo), the bass quality was outstanding......
Other than the cancellation issue, open baffle bass seems stupid to me. You are fighting to reproduce the low frequencies due to the cancellation. I will try infinite baffle bass and I anticipate staying with it unless the room nodes are really, really bad. But the NaO webpage was the first data I have seen concerning open baffle bass, and I did not see any differences in terms of room nodes from that data when comparing it to sealed subwoofer frequency sweeps.
I remember that the IB guy (Thomas) said that he tried open baffle bass comparing it to IB bass and found very little difference, except for the ability to reproduce the lowest frequencies. People on that site all the time claim that IB bass is the best that they have heard, and I imagine that they have heard horn bass. Many people say that Dr. Edgar's horn sub is the best bass that they have heard. I have heard his horn subwoofer several times, and in all three cases, it was certainly not the best I have heard - it is just OK. Perhaps if people tweak their Edgar horn subs the bass would be a lot better. Finally, Horns subs are NOT directional. They act like monopoles just like sealed subs.
Retsel
When you took the speaker out of the box, you changed the directivity of the speaker. It went from a monopole to a dipole. And guess what Rob's horn and your dipole both had in common? That's right, controlled directivity."
My observations were not based on listening, but on watching the driver. Playing the same piece of music with something like 100 hz material, the driver went from overdamped when mounted in the box to reproducing the music with significantly improved accuracy. I went back and forth between the two and the differences were startling. This expains the much greater transparency and accuracy one notices with open baffle speakers. After this observation, I was sold on speakers "without backs." Incidently, when that subwoofer was functioning correctly (it had a servo), the bass quality was outstanding......
Other than the cancellation issue, open baffle bass seems stupid to me. You are fighting to reproduce the low frequencies due to the cancellation. I will try infinite baffle bass and I anticipate staying with it unless the room nodes are really, really bad. But the NaO webpage was the first data I have seen concerning open baffle bass, and I did not see any differences in terms of room nodes from that data when comparing it to sealed subwoofer frequency sweeps.
I remember that the IB guy (Thomas) said that he tried open baffle bass comparing it to IB bass and found very little difference, except for the ability to reproduce the lowest frequencies. People on that site all the time claim that IB bass is the best that they have heard, and I imagine that they have heard horn bass. Many people say that Dr. Edgar's horn sub is the best bass that they have heard. I have heard his horn subwoofer several times, and in all three cases, it was certainly not the best I have heard - it is just OK. Perhaps if people tweak their Edgar horn subs the bass would be a lot better. Finally, Horns subs are NOT directional. They act like monopoles just like sealed subs.
Retsel
Patrick Bateman said:
I don't understand how you would rate a drivers accuracy by watching it. Can you elaborate?
Do you care about the power response? If so, then Linkwitz, Geddes, Kreskov make a lot more sense. If you care about what the room is doing to your music, it's a admirable solution.[/quote]
Au Contraire. Once the mouth sizes start getting huge, horn subs have controlled directivity. For example, a lab sub becomes directional at 314hz. That may sound very high, until you consider that's less than one octave above it's passband. A dipole is far more directional, of course.
:: PB ::
RobWells said:
Rob,
How wild would it be to build a LabSub with a modern low-distortion driver? Even Danley has discussed having Eminence add copper to the motor.
Did you know that there's a 12" out there with parameters similar to the lab sub, but it has a shorting ring? On top of that, it seems to have something like XBL in the motor. On top of THAT, it's *cheaper* than the Lab12.
It goes without saying that it would be an attractive alternative to the LAB12.
Here are the params, if you're curious.
Maximum thermal powerhandling: 1000 watts with typical music
Mechanical powerhandling depends on box and program material.
Single 4 ohm voice coil
QTS: .354
FS: 25hz
VAS: 41.7 L
RE: 3.6 Ohm
BL: 22
SPL: 84.3 dbwm
Le: 1.3mh
Xmax: 23mm 1 way (71% bl, 25% cms)
Xmech: 64mm peak to peak
Weight: 37 lbs
Cutout diameter: 28cm
Mounting depth: 16cm
Driver volume: .15 cft
Price: $130
Re: if you look...
Oh I agree with Tom, definitely. Adding copper to the motor raises the cost. And for prosound use, few people will notice the improvement. On top of that, it has *extremely* low distortion in the passband.
But what Rob is doing is different. He's the kind of guy that can hear the distortion. And don't you think that 10db of EQ will increase the distortion a great deal?
If the driver wasn't $130, I wouldn't suggest it. It's a steal!
:: PB ::
moray james said:
Oh I agree with Tom, definitely. Adding copper to the motor raises the cost. And for prosound use, few people will notice the improvement. On top of that, it has *extremely* low distortion in the passband.
But what Rob is doing is different. He's the kind of guy that can hear the distortion. And don't you think that 10db of EQ will increase the distortion a great deal?
If the driver wasn't $130, I wouldn't suggest it. It's a steal!
:: PB ::
Ok post the url....
I find this style of jerking the carrot very frustrating. If you want to post it do so if you need something other from the forum get help . You seem to make a habit of this sort of thing. You might try asking yourself what it is you think tat you gain by doing this. Moray James.
I find this style of jerking the carrot very frustrating. If you want to post it do so if you need something other from the forum get help . You seem to make a habit of this sort of thing. You might try asking yourself what it is you think tat you gain by doing this. Moray James.
Re: Re: if you look...
Make sure you add import duty / VAT / and shipping to the UK to the price. Makes it very impractical to buy drivers from the US.
I'm pretty much satisfied with what I have for now - will need a bigger room to really 'go to town' on my subs.
btw, I use my labs crossed 4th order at 80Hz, so they are not really directional apart from their 'corner loadedness'
Any pointers on a series tuned sub with a passband in the 5Hz- 25Hz region? That would be interesting.
Cheers,
Rob.
Patrick Bateman said:
Make sure you add import duty / VAT / and shipping to the UK to the price. Makes it very impractical to buy drivers from the US.
I'm pretty much satisfied with what I have for now - will need a bigger room to really 'go to town' on my subs.
btw, I use my labs crossed 4th order at 80Hz, so they are not really directional apart from their 'corner loadedness'
Any pointers on a series tuned sub with a passband in the 5Hz- 25Hz region? That would be interesting.
Cheers,
Rob.
Re: Ok post the url....
Is it safe to say we both have an interest in Danley's work? I've seen your posts on his forum, and I'm sure you've seen my Unity project. Besides John Sheerin, I'd say I have the best-documented Unity project on the 'net now.
So if that's the case, what's up with the personal attacks?
Aren't we all after the same thing here?
:: PB ::
moray james said:
Is it safe to say we both have an interest in Danley's work? I've seen your posts on his forum, and I'm sure you've seen my Unity project. Besides John Sheerin, I'd say I have the best-documented Unity project on the 'net now.
So if that's the case, what's up with the personal attacks?
Aren't we all after the same thing here?
:: PB ::
No the tempests are sitting around doing nothing right now. I can 'throw together' a vented or 6th order BP to get 'in the teens'. As I've already stated its the area below 10Hz that I'm interested in. Thats why I initially stated that I felt sealed alignments always model best for 'ultra low bass'
I said before I'd build the box over Christmas if you gave me the specs of a series tuned BP for the tempests. Looks like Christmas is over now... I have managed to cut the panels for 2 labhorns in the last few days so at least I got something done.
What would you do with a tempest in a series tuned BP in the 5Hz - 25Hz region ?
C'mon - throw us a carrot
Rob.
I said before I'd build the box over Christmas if you gave me the specs of a series tuned BP for the tempests. Looks like Christmas is over now... I have managed to cut the panels for 2 labhorns in the last few days so at least I got something done.
What would you do with a tempest in a series tuned BP in the 5Hz - 25Hz region ?
C'mon - throw us a carrot
Rob.
That's right you said it...
you can take it as a personal attack if you want, ban me from your buddy list. I guess that it reads better if you spin it that way. You are still doing the same thing. Keep your carrot you need it more than me. If you cannot see what you are doing that's too bad. I don't like the game and I don't want to play.
you can take it as a personal attack if you want, ban me from your buddy list. I guess that it reads better if you spin it that way. You are still doing the same thing. Keep your carrot you need it more than me. If you cannot see what you are doing that's too bad. I don't like the game and I don't want to play.
RobWells,
Post#373:
I think I may have the same goal as you, to extend the sub range to below 10 Hz and for that purpose use a dedicated single infra speaker.
This extension does not eliminate the need for preferably several subs placed for maximum room performance and also to maintain the important lateral cues covering from about 80 Hz down to the lowest room modal frequency at almost tactical levels for HT use.
Loudspeaker and listener positions for optimal low-frequency spatial reproduction in listening rooms. http://world.std.com/~griesngr/asa05.pdf, a must read and to take into consideration when seriously placing conventional subs for optimal result.
I have found that all other trials of explanations/approaches or instructions found at the Internet how to place subs or speakers covering the modal region are less useful in comparison with what Griesinger’s is stating, his insights in this matter is unsurpassed and I recommend all DIY’rs to read the paper more than once and contemplate and to discuss the content, maybe at this forum.
I made some experiments just before Christmas after finishing building a net 328 L closed sub with AURA NS18-992-4A for a friend of mine.
I measured with this speaker a useful –3 dB point for infra extension of my room close to 8 Hz at my listening position after equalizing the speaker and levelling out the room modals to about 80 Hz to as flat FR as possible.
With room gain included/+18 dB at 8 Hz I found that below 10 Hz my room is only capable to accommodate a maximum 90 dB SPL from an infra speaker before noise and rattling sounds from the ceiling and walls appeared very annoying.
The useful infra region for my listening room is thus the frequency bandwidth from the lowest room modal frequency (in my case; about 26 Hz) and lower and when including my room gain, there is no need for me to reach lower than f – 3 dB 8 Hz/ 90 dB SPL.
I started looking for low distortion drivers and less expensive than the $ 882 Aura driver and found two possible candidates that I simulated in a DBR enclosure to be used only in the infra region.
Placed standing straight up or laying down hidden anywhere in the HT listening room, I think this infra speaker will perform well and for most bass enthusiasts as expected. See the plots.
I’ve also modelled a ‘Giant’ box with the Aura driver for larger rooms.
See the plot.
Happy New Year!
b
1(4)
Post#373:
Hi,
I think I may have the same goal as you, to extend the sub range to below 10 Hz and for that purpose use a dedicated single infra speaker.
This extension does not eliminate the need for preferably several subs placed for maximum room performance and also to maintain the important lateral cues covering from about 80 Hz down to the lowest room modal frequency at almost tactical levels for HT use.
Loudspeaker and listener positions for optimal low-frequency spatial reproduction in listening rooms. http://world.std.com/~griesngr/asa05.pdf, a must read and to take into consideration when seriously placing conventional subs for optimal result.
I have found that all other trials of explanations/approaches or instructions found at the Internet how to place subs or speakers covering the modal region are less useful in comparison with what Griesinger’s is stating, his insights in this matter is unsurpassed and I recommend all DIY’rs to read the paper more than once and contemplate and to discuss the content, maybe at this forum.
I made some experiments just before Christmas after finishing building a net 328 L closed sub with AURA NS18-992-4A for a friend of mine.
I measured with this speaker a useful –3 dB point for infra extension of my room close to 8 Hz at my listening position after equalizing the speaker and levelling out the room modals to about 80 Hz to as flat FR as possible.
With room gain included/+18 dB at 8 Hz I found that below 10 Hz my room is only capable to accommodate a maximum 90 dB SPL from an infra speaker before noise and rattling sounds from the ceiling and walls appeared very annoying.
The useful infra region for my listening room is thus the frequency bandwidth from the lowest room modal frequency (in my case; about 26 Hz) and lower and when including my room gain, there is no need for me to reach lower than f – 3 dB 8 Hz/ 90 dB SPL.
I started looking for low distortion drivers and less expensive than the $ 882 Aura driver and found two possible candidates that I simulated in a DBR enclosure to be used only in the infra region.
Placed standing straight up or laying down hidden anywhere in the HT listening room, I think this infra speaker will perform well and for most bass enthusiasts as expected. See the plots.
I’ve also modelled a ‘Giant’ box with the Aura driver for larger rooms.
See the plot.
Happy New Year!
b
1(4)
Attachments
Happy New Year!
Get rid of the comma at the end: http://world.std.com/~griesngr/asa05.pdf
Better yet, go to the main site and you can keep yourself busy for the next year or so: http://world.std.com/~griesngr/
GM
Get rid of the comma at the end: http://world.std.com/~griesngr/asa05.pdf
Better yet, go to the main site and you can keep yourself busy for the next year or so: http://world.std.com/~griesngr/
GM
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