I modeled this driver in a rather simplistic program (WinISD) and it showed F3= 21Hz in a 4.4 ft^3 box @ 23.36 tuning, recomended. This seems more than a little optimistic for an eight-inch driver.
Can I really get that, or will I compromise a tremendous amount of power handling? This is a eight-inch driver; can I get that kind of LF extension and still play on up to the 5.5K listed? It'd make the dickens of a nice two way, bandwidth-wise, if this is actually possible, but perhaps lousy midrange (?) p'raps work better as a sub....
Any input greatly appreciated.
thanks,
-fortyquid
Can I really get that, or will I compromise a tremendous amount of power handling? This is a eight-inch driver; can I get that kind of LF extension and still play on up to the 5.5K listed? It'd make the dickens of a nice two way, bandwidth-wise, if this is actually possible, but perhaps lousy midrange (?) p'raps work better as a sub....
Any input greatly appreciated.
thanks,
-fortyquid
I just modelled it in Unibox. The LF response does look good.
123.4 litre enclosure (4.358 cuft)
Tuned to 21.93 Hz
f3=19.77 Hz
It will give 96db SPL (@10 watts input) within linear excursion (befoore room gain etc.)
It's got my interest.
123.4 litre enclosure (4.358 cuft)
Tuned to 21.93 Hz
f3=19.77 Hz
It will give 96db SPL (@10 watts input) within linear excursion (befoore room gain etc.)
It's got my interest.
Using the 'baffled' specs (the more accurate of the two of what's available), I get different values depending which program I use for a max flat alignment, but I prefer to err on the large side, so 4.89ft^3/21.04Hz Fb with a 12.8W max power handling in the ~28-35Hz BW, rising to peak rated power at ~73Hz, so it is too good to be true WRT its LF/sub applicability beyond PC/HT apps or typical TV listening levels.
For maximizing its potential, it looks really good down to 30Hz in a stuffed 2.5ft^3/35Hz Fb with a 'rumble' filter or other type of EQ to roll it off below 30Hz.
GM
For maximizing its potential, it looks really good down to 30Hz in a stuffed 2.5ft^3/35Hz Fb with a 'rumble' filter or other type of EQ to roll it off below 30Hz.
GM
Hi GM,
Do you mean because of its limited output SPL (limited by xmax), or did the 73Hz figure have something do with it?
Morning,
Both. Since the standard XO point in HT is 80-100Hz and below ~73Hz it's Xmax limited...... factor in its so-so efficiency/Pe and there's just not much linear dynamic headroom available.
For sims to be remotely meaningful, you must use a program that gives some idea of its displacement limited output.
GM
Both. Since the standard XO point in HT is 80-100Hz and below ~73Hz it's Xmax limited...... factor in its so-so efficiency/Pe and there's just not much linear dynamic headroom available.
For sims to be remotely meaningful, you must use a program that gives some idea of its displacement limited output.
GM
ELF
It looks as if a pair of them would make a killer ELF design in a 2cu.ft. enclosure with 6db boost @ 30Hz. 272W would give about 106Db @ 30Hz., f3- 25Hz
Comments?
It looks as if a pair of them would make a killer ELF design in a 2cu.ft. enclosure with 6db boost @ 30Hz. 272W would give about 106Db @ 30Hz., f3- 25Hz
Comments?
NOt even in a half-sized enclosure? I thought that this would increase the power handling significantly....? Isn't that the point of ELF allignment? That the driver can handle the extra watts necessary to make up for the EQ because the box is so much smaller creating a more resistive pneumatic "spring" to support the driver at high SPLs?
2 units in parallel closed box 2cuft:
f3: 44.5Hz
max excursion reached at 30Hz with 26 watts input
95.4db SPL @ 30Hz
2 units in parallel ported box 2cuft:
f3: 38.02Hz
excursion peak at 45Hz with 46 watts input
98.6db SPL @ 30Hz
2 units in parallel, compond, ported box 2cuft:
f3: 20.51Hz
excursion peak at 30Hz with 20 watts input
95.8db SPL @ 30Hz
As mentioned, you need to look at the excursion graphs together with the SPL level. Put WinISD aside and try Unibox.
I'm unsure as to how the phenomenon you mention works exactly, but I can see no way of achieving 106db SPL level with two of those drivers. GM will enlighten us both with a technical answer I'm sure.
Given that you want it to handle more power by reducing the box size and thus increase the stiffness, this would mean that although it handles more power, the cone doesn't move as much, and you need to move more air get a higher SPL at the end of the day.
You simply can't get past the cap on driver's excursion - xmax.
f3: 44.5Hz
max excursion reached at 30Hz with 26 watts input
95.4db SPL @ 30Hz
2 units in parallel ported box 2cuft:
f3: 38.02Hz
excursion peak at 45Hz with 46 watts input
98.6db SPL @ 30Hz
2 units in parallel, compond, ported box 2cuft:
f3: 20.51Hz
excursion peak at 30Hz with 20 watts input
95.8db SPL @ 30Hz
As mentioned, you need to look at the excursion graphs together with the SPL level. Put WinISD aside and try Unibox.
I'm unsure as to how the phenomenon you mention works exactly, but I can see no way of achieving 106db SPL level with two of those drivers. GM will enlighten us both with a technical answer I'm sure.
Given that you want it to handle more power by reducing the box size and thus increase the stiffness, this would mean that although it handles more power, the cone doesn't move as much, and you need to move more air get a higher SPL at the end of the day.
You simply can't get past the cap on driver's excursion - xmax.
So you're saying I can't just EQ the thing at the expense of some efficiency? I was under the impression that
1) one could EQ down (i.e., apply graduated attenuation to the upper frequencies) all one liked without hurting anything, and
2) one could increase the power handling throughout the BW of the driver by increasing the driver's pneumatic support at the cost of a somewhat steeper LF rolloff.
WinIsd (I havn't got Excel anything-but-a-reader, so I can't use UniBox or practically anything else, for that matter...) would have it that, when loaded in a sealed 1cu.ft. chamber, this driver will start a 12Db/Octave rolloff @ 50Hz or so producing 30Hz @ 100 Db when recieving 150W. Assuming the above I could input a 6Db boost (12Db/Octave Lp slope) @ 30Hz, cut the gain pot. 6Db and achieve an F3 of about 28Hz, 100Db, SPL. I'm not trying to annoy the neighbors, just looking for good extension. And I can adjust the sensitivity for more SPL at the expense of LF extension, handy for outdoor parties and whatnot......
Anybody know of another good simulator that doesn't require Excel?
Thanks for the help,
-fortyquid
1) one could EQ down (i.e., apply graduated attenuation to the upper frequencies) all one liked without hurting anything, and
2) one could increase the power handling throughout the BW of the driver by increasing the driver's pneumatic support at the cost of a somewhat steeper LF rolloff.
WinIsd (I havn't got Excel anything-but-a-reader, so I can't use UniBox or practically anything else, for that matter...) would have it that, when loaded in a sealed 1cu.ft. chamber, this driver will start a 12Db/Octave rolloff @ 50Hz or so producing 30Hz @ 100 Db when recieving 150W. Assuming the above I could input a 6Db boost (12Db/Octave Lp slope) @ 30Hz, cut the gain pot. 6Db and achieve an F3 of about 28Hz, 100Db, SPL. I'm not trying to annoy the neighbors, just looking for good extension. And I can adjust the sensitivity for more SPL at the expense of LF extension, handy for outdoor parties and whatnot......
Anybody know of another good simulator that doesn't require Excel?
Thanks for the help,
-fortyquid
>It looks as if a pair of them would make a killer ELF design in a 2cu.ft. enclosure with 6db boost @ 30Hz. 272W would give about 106Db @ 30Hz., f3- 25Hz
Comments?
====
Yeah, it's depressingly obvious that you're not heeding my advice.
====
>NOt even in a half-sized enclosure? I thought that this would increase the power handling significantly....?
> Isn't that the point of ELF allignment? That the driver can handle the extra watts necessary to make up for the EQ because the box is so much smaller creating a more resistive pneumatic "spring" to support the driver at high SPLs?
====
It is, but that doesn't necessarily mean it will play any louder. It just means it will take more power in a small cab to excurse 'x' amount than in a bigger cab. No one's gotten around Hoffman's Iron Law yet AFAIK.
====
>GM will enlighten us both with a technical answer I'm sure.
====
We don't seem to be 'getting through', so maybe JM's article will help: http://www.trueaudio.com/st_trade.htm
Small BP designs can 'compress' a driver to a much higher efficiency over a very narrow BW, but for it to work over a wide BW, a horn large enough for the BW must be attached, and for LF, they're huge.
====
>Anybody know of another good simulator that doesn't require Excel?
====
I often use a registered version of BoxPlot ($25) for quickie sims/comparisons. Here's the demo version:
http://www.speakerbuilding.com/software/ware/boxplot3.zip
It's 'crippled' of course, but here's what you get with the registered version:
-----
More Box types (Isobaric, Push-Pull, BandPass)
More box enclosure shapes (Tubular, slant, trapazoids)
2 and 3 way passive crossovers designs
More passive crossover types (1st thru 4th order)
Zobels, notch compensator and other passive networks
Active crossover networks and filters (1st through 4th Order)
Box measurement and tuning section
More driver librarys from popular manufacturers.
Text file import of driver data
Complete on-line help and tutorial on speaker building
Plus notification of upgrades and bug fixes as they are available.
Included in the on-line documentation is a mini tutorial on Loudspeaker
enclosure design, construction, and tuning.
-----
For serious designing, I use Lspcad, a very powerful/accurate and inexpensive program for what it can do: http://www.ijdata.com/
GM
Comments?
====
Yeah, it's depressingly obvious that you're not heeding my advice.
====
>NOt even in a half-sized enclosure? I thought that this would increase the power handling significantly....?
> Isn't that the point of ELF allignment? That the driver can handle the extra watts necessary to make up for the EQ because the box is so much smaller creating a more resistive pneumatic "spring" to support the driver at high SPLs?
====
It is, but that doesn't necessarily mean it will play any louder. It just means it will take more power in a small cab to excurse 'x' amount than in a bigger cab. No one's gotten around Hoffman's Iron Law yet AFAIK.
====
>GM will enlighten us both with a technical answer I'm sure.
====
We don't seem to be 'getting through', so maybe JM's article will help: http://www.trueaudio.com/st_trade.htm
Small BP designs can 'compress' a driver to a much higher efficiency over a very narrow BW, but for it to work over a wide BW, a horn large enough for the BW must be attached, and for LF, they're huge.
====
>Anybody know of another good simulator that doesn't require Excel?
====
I often use a registered version of BoxPlot ($25) for quickie sims/comparisons. Here's the demo version:
http://www.speakerbuilding.com/software/ware/boxplot3.zip
It's 'crippled' of course, but here's what you get with the registered version:
-----
More Box types (Isobaric, Push-Pull, BandPass)
More box enclosure shapes (Tubular, slant, trapazoids)
2 and 3 way passive crossovers designs
More passive crossover types (1st thru 4th order)
Zobels, notch compensator and other passive networks
Active crossover networks and filters (1st through 4th Order)
Box measurement and tuning section
More driver librarys from popular manufacturers.
Text file import of driver data
Complete on-line help and tutorial on speaker building
Plus notification of upgrades and bug fixes as they are available.
Included in the on-line documentation is a mini tutorial on Loudspeaker
enclosure design, construction, and tuning.
-----
For serious designing, I use Lspcad, a very powerful/accurate and inexpensive program for what it can do: http://www.ijdata.com/
GM
====
....it's depressingly obvious that you're not heeding my advice.
====
Well, thanks for the advice, but it's kind of big (the system). I'm wondering about ELF now; you had suggested a BR., and I was trying to use a smaller enclosure at the cost of some efficiency. I'm all of eighteen years old with about 18 months of experience limited to WinISD and one driver in four different box types (BR, TL, 6thOrderBP, and Sealed); please, I'm just trying to understand. Its hard to learn without asking questions.
====
It is, but that doesn't necessarily mean it will play any louder. It just means it will take more power in a small cab to excurse 'x' amount than in a bigger cab.
====
Are you saying that by decreasing enclosure size the efficiency will actually change over the whole BW or just cause a steeper LF roll-off? WinISD only shows a steeper roll-off, so that's all I know about. If it's just a steeper roll-off as shown by the SPL graph then (correct me?) I can EQ at the cost of efficiency; 6Db, if I want it flat to 30Hz, or less or more as I please.
http://65.104.178.66/bagendnew/what_is_elf.htm
or, if you have a few minuets
http://65.104.178.66/bagendnew/downloads/elfguide13w.pdf
Now this, of course, depends upon the accuracy of the WinISD SPL graph. It shows that the Peerless 831709 loaded in a sealed, 1cu.ft box will, if fed a 100W signal @ 20Hz, will play at 96Db. Implementing an active EQ I can apply graduated attenuation to the upper frequencies, thus producing a flat response to 20H.
====
No one's gotten around Hoffman's Iron Law yet AFAIK.
====
I haven't, as I understand it. I have payed dearly for my extension in efficiency, right?
Did I do this right?
Or is it like this:
The SPL graph is more like a PE graph. If a driver exhibits a LF rolloff, it represents a corrolative reduction in power handling; a 6Db drop in SPL, by the graph, means a quartering of PE. So, assuming the above signal/frequency/driver/allignment as above, I can only send the driver 8W, which will actually only go to 80Db, as the efficiency at this frequency is 71Hz Db/W.
Very much indebted to you,
-fortyquid
....it's depressingly obvious that you're not heeding my advice.
====
Well, thanks for the advice, but it's kind of big (the system). I'm wondering about ELF now; you had suggested a BR., and I was trying to use a smaller enclosure at the cost of some efficiency. I'm all of eighteen years old with about 18 months of experience limited to WinISD and one driver in four different box types (BR, TL, 6thOrderBP, and Sealed); please, I'm just trying to understand. Its hard to learn without asking questions.
====
It is, but that doesn't necessarily mean it will play any louder. It just means it will take more power in a small cab to excurse 'x' amount than in a bigger cab.
====
Are you saying that by decreasing enclosure size the efficiency will actually change over the whole BW or just cause a steeper LF roll-off? WinISD only shows a steeper roll-off, so that's all I know about. If it's just a steeper roll-off as shown by the SPL graph then (correct me?) I can EQ at the cost of efficiency; 6Db, if I want it flat to 30Hz, or less or more as I please.
http://65.104.178.66/bagendnew/what_is_elf.htm
or, if you have a few minuets
http://65.104.178.66/bagendnew/downloads/elfguide13w.pdf
Now this, of course, depends upon the accuracy of the WinISD SPL graph. It shows that the Peerless 831709 loaded in a sealed, 1cu.ft box will, if fed a 100W signal @ 20Hz, will play at 96Db. Implementing an active EQ I can apply graduated attenuation to the upper frequencies, thus producing a flat response to 20H.
====
No one's gotten around Hoffman's Iron Law yet AFAIK.
====
I haven't, as I understand it. I have payed dearly for my extension in efficiency, right?
Did I do this right?
Or is it like this:
The SPL graph is more like a PE graph. If a driver exhibits a LF rolloff, it represents a corrolative reduction in power handling; a 6Db drop in SPL, by the graph, means a quartering of PE. So, assuming the above signal/frequency/driver/allignment as above, I can only send the driver 8W, which will actually only go to 80Db, as the efficiency at this frequency is 71Hz Db/W.
Very much indebted to you,
-fortyquid
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