I am not. Even if I was, I can see how changing the law can create big waves in society. Noone likes to see god bleed. I am sorry.
It was not the topic to discuss, it was not for you primarily. That is okay (except for ruined topic). At least we had fair run. We tried. The disagreement is good and healthy. Do not feel that bad about it. Never give up. 💪
Err, no, U. But that is okay. I sincerely without any trolling would give you a cookie, to calm down. Sheesh, this is just a chat. If you make such claims, it is normal to expect resistance and asking for evidence.
There may be more driving force, but it's likely to be necessary to include the damping in the system's equations of motion. In the end, one listens to the SPL frequency response of the system. If the bass is attenuated relative to the midband, the system will be perceived as not having much bass, will it not? Using amplifier power to shape the low-frequency response is not particularly new, as a few people have studied the topic of filter-assisted low-frequency alignments over the past few decades.
What? Filter-assisted low-frequency alignments aren't reasonably well understood? I'm not sure that's entirely correct. Take a look at the following figure, which comes from A. N. Thiele's paper, "Loudspeakers in Vented Boxes: Part 1", Journal of the Audio Engineering Society, Volume 19, Issue 5, pp. 382–392, May 1971 (Reprinted from Proceedings of the IRE Australia, Volume 22, pp. 487–508, August 1961). What you are describing is using an auxiliary filter to boost the low-frequency output of a woofer in its enclosure. Doesn't this concept look familiar to you?
Thiele also noted that the expression for efficiency (Equation 15 in the referenced paper) contains three parts:
1) a constant part containing physical constants,
2) a constant part containing speaker parameters,
3) a part |E(jω)|² which varies with frequency.
A small correction is needed, based on prior published work in the available audio literature: EQing has for many decades been a normal process of getting the needed frequency response. See for details: Thiele, A. N. (1971). Loudspeakers in Vented Boxes: Part 1. Journal of the Audio Engineering Society, Volume 19, Issue 5, pp. 382–392. In his paper, Thiele noted:
"The choice of alignment will depend largely on what can be done with the amplifier circuits. ... If a more sophisticated design of input filtering is possible as described in Sections V and XII, alignments 15-17 can be used to obtain good acoustic output from small boxes at the expense of higher electrical power output from the amplifier, while alignments no. 20-25 are the most suitable if a fair sized box is available and only moderate lift is required from the amplifier, although in all the fifth- and sixth-order cases, the power required from the amplifier and the excursion demanded of the speaker decrease rapidly below cutoff."
It is perfectly okay that something gives you wrong idea, because it shows you wrong or unsuitable data. The point is in understanding why it is not good piece of data, and why it is wrong idea. So what happens here is that you are putting two different drivers, in two differently sized boxes, with two different tuning frequencies with two different power inputs feeding these, and wondering about the outcome, that does not come in line with the claim, that more force on the coil means more SPL. That´s why you get the wrong data.
You need to put it in the same box, same tuning, and feed it the same real power. Then the outcome will be very different. WinISD alone cannot do that for you. It can only provide you some datapoints, with which you can create such graph, as I did.
If you can, please set the same circumstances, I will plot the outcome, and we can discuss why is that, where it comes from, and such.
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Regarding electrical damping, it is not a loss, it is an impedance. And indeed, we do include that in the impedance and phase data sets. That´s why damped system need more voltage, to overcome the impedance. From that angle of view, more voltage does not mean excessive power. It means proper, reference, same power as with undamped system.
Regarding mechanical damping, now we´re talking, and you are right. Yet we can momentarily skip the underlying factors, we can hop fast forward, compare outcomes, and see if it is worth to continue. And it seems it is. The mechanical damping is not that bad, and strong motor can overcome that with authority, more so at low frequencies.
Yes, that will happen. But it is just perception, not the absolute numbers. It is the core of all this. If the driver provides more bass, and extremely more mid bass, it doesn´t mean it does not produce bass. It does, it does it better still, and so we reap it. For sake of usability, we either EQ the bass up, or the midbass down. Still, we end up with more efficient and powerful system.
It is not exactly power. It is more of voltage. The amplifier not able to put out like 140-160VRMS will not do that at full power for such speaker. As it will not be able to provide the power into the high impedance driver.
No. Speaker power (mean force) is clearly not understood.
That is where it led to, but that is not what I am describing.
Yeah, that is little far into the offtopic.
No, not really. The context is different. In their timeframe, the EQ came with the cost of more power. For high force driver, EQ does not come with the same cost. It is absolutely necessary part, to get about "any power" to the speaker to play. That´s where the misunderstanding is. The term "at expense of higher electrical power output from the amplifier" is not applicable here. As the system took less power in the begining. So we are equalizing it literally. Not boosting up. Equalizing for fair comparison. No expense on top of some arbitrary chosen base. By EQing, we are rising it to the same base. To the same power draw.
//I greatly encourage people to study stepper motors and stepper drivers. What does it take to feed the motor, so it is capable of any usable accelerations and speed and power. These motors are marked in ballpark of 2-6V of working voltage, yet these are fed by 48V or more volts. There are more reasons for such difference, as high frequency, yet the topic is very related.
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I did that also, but neither are suited for my box. At 75 liter I get a 3db boost from 40-60Hz with the Seas A26RE4, leading to a quite boomy sound that can be heard in the video I posted with the red horn. It is great at lower SPL because the way nervous system interprets bass at low listening levels. Not so great at high listening levels. I am not used to so much low bass so I got a bit seasick. I will slap on an extra magnet and see if that helps the Seas with increased flux. Or just use the W26FX002 which fits perfectly in a 75L box with a low tune which results in a 1dB bass boost for my low level listening sessions.
The B&C needs a smaller 37 liter box with higher tune at 48Hz to achieve a flat response. Otherwise, if you try to squeeze out more bass in a bigger box, you get a dip below 200Hz which is not ideal. I saw the same thing in Faital Pro 15PR400.
At least according to Winisd.
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Perfectly understandable. The situation takes much more management to get certain outcome for the ear. I am with you on that. But it has not much to do with efficiency of a driver. It can be inefficient and boomy, efficient and boomy, inefficient and not boomy, efficient and not boomy.
I get your point, yet it does not relate to mine at all.
I would not call it a need of a driver, but for your need for flat response, indeed that is the setup.
That is a wrong need altogether. You are not supposed to need this from a driver, you are supposed to need it from the SYSTEM. And so you tune the driver according to your different needs, and you equalize the frequency response afterwards for your needs. Those needs are not mutually exclusive. It is just that they need to be managed separately. They truly do. The driver is constructed in such way. It will not be happy in 37l box for various reasons, it is unsuitable to do that to the speaker. The simulator choses to do unsuitable stuff, for sake of flat response, that is also not needed at speaker level.
So either your system requirements are:
- midbass only in a smaller box with flat response (which is not an unworthy goal)
Or…
- EQ bass boost below 200Hz in a larger box.
Did I miss something?
Can you provide the following frequency response diagrams for your system and the amplifier that was used?
1) The frequency response of the complete system.
2) The frequency response of the EQ that is implemented in the system.
3) The frequency response of the woofer mounted in the enclosure.
4) The impedance response of the woofer mounted in the enclosure.
Not sure I understand the following, but I will try to respond.
Bass according to my needs. No flat response needed at speaker level. The flat response will be set by EQing at system level.
In general, it will take more power to get that for high SPL application, it is inevitable. But it will take LESS power than with weaker driver. The high SPL density can only be achieved with a driver that has strong (Newtons) motor. A weak driver cannot do that at all. Again, flat response on a speaker level is not a goal to follow. A driver, with strong motor, big coil, big power input and big displacement volume is not a midbass. It is unfortunate people look at it that way, because it is very sensitive at midbass. It seems I still didn´t do good job in explaining the problematics. We might try to compare some ad absurdum case of very shitty driver, with very strong driver. How about that?
I se no firm connection between box size. Think of it as a speaker without motor first. The speaker has some properties. Cone area, displacement and such.
Why should strength of the motor dictate anything? As long as the displacement volume is capable of creating wanted SPL, and the coil will not burn, you can put any motor on it. The point is that with strong motor, it takes least watts. Again, wrong worldview. If a high Qes weak driver gives you flat response, and low Qes strong driver gives you lower output, but the physical cone, surround, spider and such are the same, it does not make sense why the strong driver should not give you at least the same amount of bass, unless you restrict it with voltage. That is unnecessary restiction.
It seems we still did not understand each other. It feels like everything is missed and misunderstood, and I have no idea what else to do about it.
For sake of arguing the same data, we can perfectly simulate this with WinISD. and Excel sheet.
RCF LF21N551, 135l of box volume, 28Hz tuning. The goal is to get best 30-90Hz efficiency with underlying potential for maximum SPL.
As an icon to compare to, I recommend B&C 18IPAL though. That will do the most of it. RCF is kind of secondary what I could afford.
Pick any other driver, that you think is more suitable for such enclosure.
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For interest sake I ran the numbers on the Seas A26RE4, 15TBW100 and 18IPAL. Enclosure used was 100L sealed in all cases. If I had the time I'd like to run some different enclosure types and sizes. If a high BL driver were chosen that hit resonance at the same frequency in 100L as the Seas, it would have had an efficiency advantage across the band.
This graph shows calculated output with one watt of input power to the three drivers. Apart from the 30 and 40Hz datapoints, where the Seas is near resonance in this 100L enclosure, the two B&C drivers have a significant lead in efficiency. Through most of the bass range the high BL drivers require about one third the power for a given output.
And here is the 2.83V graph. The IPAL driver has a 6dB sensitivity advantage from its 2R coil, the other two drivers are 8R, nominal. The normalised graph at post #57 is very misleading because it uses the inherent sensitivity advantage of the 15TBW100 against it. The reality is that in the low bass, with the same voltage drive to both drivers the Seas driver has a 1dB advantage.
I encourage others in this thread to run the numbers on a few different drivers in different enclosures to see what results they achieve. If you do please share your results here so we can all learn.
This graph shows calculated output with one watt of input power to the three drivers. Apart from the 30 and 40Hz datapoints, where the Seas is near resonance in this 100L enclosure, the two B&C drivers have a significant lead in efficiency. Through most of the bass range the high BL drivers require about one third the power for a given output.
And here is the 2.83V graph. The IPAL driver has a 6dB sensitivity advantage from its 2R coil, the other two drivers are 8R, nominal. The normalised graph at post #57 is very misleading because it uses the inherent sensitivity advantage of the 15TBW100 against it. The reality is that in the low bass, with the same voltage drive to both drivers the Seas driver has a 1dB advantage.
I encourage others in this thread to run the numbers on a few different drivers in different enclosures to see what results they achieve. If you do please share your results here so we can all learn.
On diyAudio you are free to debate ideas. You are not free to insult forum members.
Actually, the OP missed the whole point about the loudspeaker efficiency. I will not discuss anything with him further, because it is a hopeless Sisyphus tusk - he doesn't have a clue about loudspeakers and physical laws governing them.
You are right about the correct way for analyzing the woofer efficiency – we have to calculate the graph of SPL(e) vs frequency with constant 1W absorbed by the woofer. To avoid confusion, let mark this “eficiency” graph as SPLe (for efficiency), in contrast to conventional SPLv (for constant 2.83V voltage input). That “eficiency” SPLe graph will follow (will look like) the graph of the woofer’s ‘Impedance vs Frequency’ measurement: where woofer impedance is high, SPLe will be higher (with the same 1W absorbed by the woofer) and conversely - where woofer impedance is low, SPLe will be lower (again, with the same 1W absorbed by the woofer).
Now, let’s analyze the simplest example – woofer in a closed box.
Example 1: Woofer in closed box has flat conventional ‘SPLv vs frequency’ graph above its cut-off frequency (-3dB) at F3=70Hz, measured with constant 2.83V. That means SPLv will be down 3dB at 70 Hz and down 12dB at 35Hz, because SPLv follows the 12dB/octave slope below F3.
Impedance vs Frequency graph will have impedance peak at about the same 70Hz. Therefore, SPLe vs frequency graph (calculated with constant 1W absorbed by the woofer) will look just like conventional ‘Impedance vs frequency’ graph - peaking at about 70Hz (SPLe70) and decreasing above and below 70 Hz. Logically, at 35Hz calculated SPLe (SPLe35) will be 9dB down (12dB-3dB=9dB) compared to SPLe70.
Let’s say we want to make a proper subwoofer from this wimpy loudspeaker, by boosting the signal at 35Hz by +9dB (8 times more Watts!!!) with DSP or IPALmod, so now we have flat frequency response from 35Hz upward. But what happens with the “green agenda: less heating-more SPL” proponed by OP? Absolutely nothing, because the DSP or IPAL equalization/correction simply inject more Watts into the loudspeaker, in order to flatten/extend the frequency response to lower frequencies. Because the woofer is the same, it is indisputable that the efficiency remains the same when using DSP or IPAL equalization/correction, only there are much more Watts injecting into the speaker and consequently - much more heating! In this example 8 times more Watts (+9dB) and 8 times more heating! There is no free lunch and there are no magical “green SPL deciBels from DSP/IPAL” from the Santa Claus bag!
Woofers in vented (bass-reflex) enclosures have one additional problem – we must not equalize/boost below the tuning frequency Fb!
Example 2: Woofer in a vented box has Impedance vs Frequency graph with one low-impedance valley at the tuning frequency Fb, and two impedance peaks above and below that valley. With conventional TS maximally flat alignment ‘SPLv vs frequency’ graph at Fb (marked SPLvb) will be -6dB down (compared to higher frequencies), measured with constant 2.83V. Therefore, SPLe vs Frequency graph (calculated with constant 1W absorbed by the woofer) will look just like ‘Impedance vs frequency’ graph’ – one valley around Fb and two peaks: one below Fb (at frequency F1) and one above Fb (at frequency F2). Therefore, SPLe vs frequency graph (calculated with constant 1W absorbed by the woofer) will look just like ‘Impedance vs frequency’ graph – one valley around Fb with low value of SPLeb and two peaks: one below Fb (SPLe1 - not interesting) and one above Fb (SPLe2 – potentially interesting). Logically, there is relation SPLeb = SPLe2 – 6dB. The problem with OP “Efficiency” graph from post #1 is that it doesn’t show any valley around tuning frequency Fb and peak at the second impedance peak – so his graph is wrong!
We can boost the signal at Fb by 6dB (4 times more Watts!!!) with DSP or IPALmod, so now we have flat frequency response from Fb upward. Again, because the woofer is the same, it is indisputable that the efficiency remains the same when using DSP or IPAL equalization/correction, only there are much more Watts injected into the speaker and consequently - much more heating! In this example 4 times more Watts (+6dB) and 4 times more heating!
But what will happen if we detune the enclosure to much lower Fb? Nothing good – then we must increase DSP/IPAL boost much more than 6dB, to obtain flat frequency response. Consequence – even more heat!
Again: woofer efficiency (the title of this thread!) is fixed by its design, IPAL and any other DSP/equalizer just injects more Watts into the woofer.
Don’t expect any joy from OP, sorry. He doesn't have a clue about loudspeakers.
Good news: high BL drivers have advantage. Bad news: high BL drivers don’t have advantage.
Moral of the story: it depends.
Below is the SPL vs frequency function for the same woofer in the same enclosure, but with three different BL values: red graph is low BL, dash-dot graph is medium BL, and dashed graph is high BL. As we can see, high BL model has highest SPL above 200Hz, but it is the weakest in the bass – below 70Hz it is beaten by both models with lower BL. Medium BL has the most extended bass below 40Hz, also has the highest SPL below 40Hz. Low BL has very narrow usable bandwidth, but is capable of the highest SPL between 40Hz and 50Hz.
But can we use the same high BL model and change its spider with softer one, to decrease the Fs (and increase the Vas), and use much bigger enclosure, to make much lower F3, maybe lower than F3 of the medium BL driver? Sure, but again we are hitting the wall of the Hoffman’s Iron Law: efficiency, low bass extension, enclosure volume – pick two only! Sorry...
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Yes, If you picked one 30Hz ported, it would show very interesting and somewhat unexpected outcome.
It seems this was not heard at all.
Welp, that is apparent power, right? Did you take into consideration real power? The one that goes into heat? Strong motor drivers have another notch there, on top of all this.
If we could use real power, I sure can do that, as I did in the first post.
The graph will follow the impedance curve the less, the more stiff suspension we have.
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@cowanaudio:
I am plotting with you. Could we please align our reference graph of A26RE4 in a 100l box?
My graph shows something little different. Pick 40Hz datapoint. I have impedance of 43,87 Ohm, Voltage of 6,6265V and SPL of 93,758dB. You have 95dB in your graph, and so we are not synced somehow. Any idea where could it come from?
Here is TS parameters I took:
http://www.seas.no/index.php?option...cle&id=90:h1411-08-a26re4&catid=44&Itemid=461
And here is the graph, incorporating real power, on top of apparent power, which is significant to the topic.
What simulator do you use?
I am plotting with you. Could we please align our reference graph of A26RE4 in a 100l box?
My graph shows something little different. Pick 40Hz datapoint. I have impedance of 43,87 Ohm, Voltage of 6,6265V and SPL of 93,758dB. You have 95dB in your graph, and so we are not synced somehow. Any idea where could it come from?
Here is TS parameters I took:
http://www.seas.no/index.php?option...cle&id=90:h1411-08-a26re4&catid=44&Itemid=461
And here is the graph, incorporating real power, on top of apparent power, which is significant to the topic.
What simulator do you use?
Yes, I wil continue presenting my data to show who is right and who is not, but you are not welcome for hostile behavior and name calling.
The idea originated from me.
With stiffer suspension, that is less of the case.
Yeah, you lost the reference. Will not work that way. A flat frequency response speaker will not have flat efficiency response. All wrong. At least I recommend bringing a real case.
It works given the proper real circumstances. We well dig that hopefully with cowanaudio.
You set wrong input data. There will be equalization and more heat, but less than with weak speaker.
One thing is that you can, and the second thing is that you simply can tune the box lower, to avoid this issue.
Yes, this is absolutely wrong, such thing is false, and does not happen. That is my opening picture in first post. The port does not increase efficiency in such way, surprisingly! Do your homework before calling people names.
That is the data, and it is right. I see how YOU have a problem finding that.
No, wrong. Cowanaudio already showed you graph with higher efficiency of PA drivers.
It is confirmed again, that he who is is right on the forum or social media is in serious trouble. Because he being right means, that others are not, and they will eat him alive. 🤣
The ignorance is sweet.
No sorry, this means you didn't get even the Hoffman's Iron Law. You are spamming my thread, spewing misinformation and being hostile. Good job.
As it turns out Hornresponse will directly plot system efficiency. Here is the Seas driver (grey) Vs the Ipal (Black):
I did do it. But just with WinISD, which simulates differently.
Still, I tried with Hornresp, and it shows me different data than yours. I do not get 95dB at 40Hz.
With 40Hz, I get 2,8V, 7,8152Ohm and 92,6591dB. We have something different.
Yes, I know that Hornresp shows efficiency, but it is only based on apparent power, not real power. And so it is still insufficient for my case.
Here is my plotting with WinISD:
As expected, the IPAL is crushing it.
Still, I tried with Hornresp, and it shows me different data than yours. I do not get 95dB at 40Hz.
With 40Hz, I get 2,8V, 7,8152Ohm and 92,6591dB. We have something different.
Yes, I know that Hornresp shows efficiency, but it is only based on apparent power, not real power. And so it is still insufficient for my case.
Here is my plotting with WinISD:
As expected, the IPAL is crushing it.