The Kappa-15LFA should also be placed in a larger enclosure if you do not want to use an EQ.
The frequency response shown in the data sheet for this driver also doesn't look like it would be advisable to drive it up to 1.6 kHz (although I wouldn't separate that high anyway, see above).
Looks like the LFA and Deltalite do the same thing.
not much below 100 Hz in huge boxes.
Eminence not so great.
Data sheets show half space measurements with no bass.
So in real life in full space, with full space losses they have absolutely no bass.
The graph clearly shows 40 Hz being down almost - 15 dB in half space.
Assume 6 dB more in full space so -21 dB = nothing will ever happen
-3 dB considered actual bandwidth. pretty much 80 Hz is what it does with no losses.
Real life, more losses.
Hence rule of thumb for any driver and the tale the impedance tells.
If Fs is 40 Hz dont expect much 2x above that. 80 Hz
Simply amazing -3 dB is basically 80 Hz.
Fs will rise in any box, so assuming a 20 Hz rise to 60 Hz, nothing much below 120 Hz.
15 " cone depending on slight variables to Sd will become directional around 1000 Hz
Crossover frequency has been and will always be 800 Hz or lower.
By the way the box and horn shown in the photo are rather well done.
Look rather nice and great craftsmanship.
not much below 100 Hz in huge boxes.
Eminence not so great.
Data sheets show half space measurements with no bass.
So in real life in full space, with full space losses they have absolutely no bass.
The graph clearly shows 40 Hz being down almost - 15 dB in half space.
Assume 6 dB more in full space so -21 dB = nothing will ever happen
-3 dB considered actual bandwidth. pretty much 80 Hz is what it does with no losses.
Real life, more losses.
Hence rule of thumb for any driver and the tale the impedance tells.
If Fs is 40 Hz dont expect much 2x above that. 80 Hz
Simply amazing -3 dB is basically 80 Hz.
Fs will rise in any box, so assuming a 20 Hz rise to 60 Hz, nothing much below 120 Hz.
15 " cone depending on slight variables to Sd will become directional around 1000 Hz
Crossover frequency has been and will always be 800 Hz or lower.
By the way the box and horn shown in the photo are rather well done.
Look rather nice and great craftsmanship.
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Shakuto, the SB 15W400 you are interested in looks like a decent choice in your volume, but tuning will want to be higher than 45Hz to get reasonably flat.
These higher tunings may warrant a separate subwoofer to fill in the lower octaves, it really depends on your preferences & listening habits.
The 40Hz tuning you are after might work if you plan to have the box closer to or maybe against a wall.
These higher tunings may warrant a separate subwoofer to fill in the lower octaves, it really depends on your preferences & listening habits.
The 40Hz tuning you are after might work if you plan to have the box closer to or maybe against a wall.
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15W400 has Qts of .33 so highly highly unlikely a actual alignment is tuned high.
The smoother roll off of low Qts drivers or powerful motors, does not mean to tune high.
Live audio drivers will always be a assisted alignment for bass in hifi applications.
Tuning high is just destroying transient response, and port efficiency is so useless.
It never will be a solution for response accuracy. Not the purpose of transfer function.
It is a theoretical filter to make the suspension happy, not to EQ
EQ is done with EQ
The smoother roll off of low Qts drivers or powerful motors, does not mean to tune high.
Live audio drivers will always be a assisted alignment for bass in hifi applications.
Tuning high is just destroying transient response, and port efficiency is so useless.
It never will be a solution for response accuracy. Not the purpose of transfer function.
It is a theoretical filter to make the suspension happy, not to EQ
EQ is done with EQ
Correct, standard tunings for 15W400 are not "high", they are 44-52Hz in 67-69L, the flattest of which is highest tuning in largest volume.
None of these boxes will dig deep.
EB tunings are significantly bigger than the OP's box, would need EQ to be flat & will have worse transients.
These designs are more suited for Pro applications where efficiency is the priority.
Going sealed in the OP's volume & using a sub (or subs) below would be more of a hifi solution.
None of these boxes will dig deep.
EB tunings are significantly bigger than the OP's box, would need EQ to be flat & will have worse transients.
These designs are more suited for Pro applications where efficiency is the priority.
Going sealed in the OP's volume & using a sub (or subs) below would be more of a hifi solution.
The frequency responses printed in data sheets are not at all suitable for assessing the bass capability of a driver. For this kind of thing you usually use the TSP and throw them into a simulation programme, for example.
With the Eminence Kappa-15LFA, for example, it is perfectly possible to reproduce 40 Hz adequately (f3), it only needs a larger cabinet than 87 litres (Vb about 120 litres @ 40 Hz fb).
The same applies to the Deltalite II 2515, although its housing would have to be even larger if no EQ is to be used (>200 litres).
Therefore, in my opinion this here.....:
....is not correct either.
If the TSPs on the first post are correct then one could use a B6 tuning in a box around 120 liters. This would ask for a highpass (usually connected between preamp and poweramp) with a Q of 2 and a pole frequency around 33 Hz. fb would also need to be around 33 hz and fc would also be around that.
Regards
Charles
Regards
Charles
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Why not just leave open holes? This woofer models well to me in an 87 liter box with a single 7cm port with 2cm port length. Two 7cm by 2cm ports appears to give a bit of a bass peak.
Have you let the driver break in for a few hours? Pro drivers have relatively stiff suspensions and often have minimal bass when new.
In my experience, it is difficult to measure bass. Just give it listen with some familiar music (preferably acoustic) and see if you like the sound.
Based on Eminence's graphs, this driver should probably sound pretty smooth in the midrange also, I wouldn't give up on it easily...
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Yes, I’ve already accepted that I won’t be able to tune it lower than 45. Let it be that way. Maybe someday I’ll build new cabinets or start a completely new project. This will be a good lesson for me.
Briefly tested in WinISD: 87 Vb with a port of 7 cm diameter and 2 cm length results in an fb of 43 Hz. In this case, tuning is of virtually no use, f3 is over 60 Hz with the Deltalite II 2515 screwed in. No, the cabinet is clearly too small especially for this driver.
And another thing: I normally aim for an area of 1/3 SD for the cross-sectional area of a port, i.e. around 260 cm² for a 15-inch driver. I do this to avoid port noise at higher volumes. However, a 7 cm port only has a cross-sectional area of 38.5 cm².... 😳
Or to put it another way: in my opinion, the flow velocity in the port should not exceed 20 m/s. If Xmax of the Deltalite II 2515 is utilised with such a small port in this housing, then this value is well over 70 m/s..... 😳😳
You can be sure of some nasty noises.
You can quickly simulate all this with programmes like WinISD, I have no idea why this is apparently not done so often. It's actually not that difficult and takes just a few minutes.
Yes, it's not as easy, but it's also not as complicated as you might think. I can think of two options for the hobby user: groundplane measurements on a large outdoor area and combined and bafflestep-corrected near-field measurements (as near as possible) that are cleverly combined with each other. 🙂
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However, this only works if any BR ports are closed. The volume must be CB.
In addition, the volume must be well-defined, so damping material would probably be counterproductive.
Why not simulate with the manufacturer's TSP first, at least for an approximation?