It is better to treat the room acoustically. Basstraps in the corners is a good start. And some absorption panels.
The inherrent problem is such that DSP does not help enough. Adding/cutting 3dB does not necessarily yield 3dB change in the measurement, and in other places of the room, it goes out of whack even more. So yeah, room treatment gets the utmost priority. Reflect, break, disperse, absorb. Employ all these tools to get it better.
In home audio, the run for maximum efficiency is not necessary indeed. You are more than fine with the Seas for normal listening levels.
In home audio, the run for maximum efficiency is not necessary indeed. You are more than fine with the Seas for normal listening levels.
There is another way to manage the bass at home, by adding multiple sources. These will average out the response dominated by room and relieve the mains from having to play to 20Hz improving midrange. Only pros audio quality wise, except now one has few more boxes to hide (can be small though), a DSP and few more amplifiers.
https://www.diyaudio.com/community/threads/multiple-small-subs-geddes-approach.134568/
https://www.diyaudio.com/community/threads/multiple-small-subs-geddes-approach.134568/
I was actually refering to this statement, not about the room "When playing at low listening levels, which I often do, I prefer a scooped graph, not the opposite. Same was the case for the 15PR400 in the same cabinet. To get more bass out of these large 15" PA woofers, I could have built a gigantic 170L cabinet, but 75L was already quite large. But they would never be scooped like these two Seas drivers."
I agree the room acoustic should be fixed before using dsp as a bandaid.
I agree the room acoustic should be fixed before using dsp as a bandaid.
Oh, in that case I think it is better to let the woofer have an abundance of bass that can later be tamed, rather than trying to add bass from nothing with EQ by lowering everything else. Hence 80's scoop mids. Dimebag would have been proud.
@brig001
@cowanaudio
I am happy to announce that we have the solution. David McBean for one reason or another knew what he is doing ahead of the time, and kindof implemented my desired function in the Hornresp, so we can reap the fruits of further analysis together.
For Max power tool, he uses the formula including CosFi on the power, and displays the output based on real heating power of the driver.
Therefore there is nothing easier, than just input 1Watt of maximum power, and compare results as well!
Here is 18IPAL versus Seas A26RE4 in 100l box tuned at ~25Hz:
It can be seen, that 18IPAL, despite having such disadvantages as much stiffer suspension and heavier cone, and higher damping with insanely low Qes, outputs more SPL per 1Watt of real power than Seas, even in bass region.
As mentioned, the massive coil of the 18IPAL will help with progressing the lead with more input power. At the point where the efficiency seems the same, very little power flows in both drivers. It doesn´t matter much, if 10Watts or 20Watts of power flows into the voice coil, because the coil can handle that without much thermal compression. But at 25Hz and ~100Hz with lowest impedance, hundreds of watts will flow, and the difference in heat strain and thus power compression and linearity will be massive.
And based on these findings I proudly stand my ground, and am super happy, that I do not have to input the data into excel table anymore.
Big thanks to Cowanaudio, VelocipedeAcoustics and David McBean!
//Also I would like to note that the SPLefficiency does not copy impedance curve nearly as much as user Sonce claimed. There is hint of it, but quite futile.
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I still would not use the 18 inch driver. Seas 10 inch sound so much better in the lower midrange with its lighter cone. And if more magnet strength is needed there is always the W26FX002.
By all means, do as you wish. This was purely efficiency topic. I would benchmark that claim of yours still, asking for data or proof, but it indeed is irrelevant here. The reason for this topic is very different.
I would like to know if such stiff suspension is really necessary, or something more can be done to the pro drivers, to linearize and ease up on the stiffnes, to get even more efficiency.
I would like to know if such stiff suspension is really necessary, or something more can be done to the pro drivers, to linearize and ease up on the stiffnes, to get even more efficiency.
Then you will like my next project. 15 inch, 3 inch VC, BL 26.4 T*m, wooden cone, 60 gram Mms, foam surround and super light thread spider.
That sounds wicked, and very interesting. Keen on the wooden sound of the cone flex. I mean both really and jokingly too. Not many people have the balls to do that and see how it goes. 💪
It's encouraging seeing essentially the same results four different ways. Perhaps Hofmann's Iron Law should be renamed Hofmann's Iron Guideline 🤔
The law works pretty well. It's just that it is just one element in the equation of the outcome.
See, we used the most efficient driver we could come up with, and it is somehow bound to produce this much SPL in that particular box. It does not mean that lesser drivers cannot play less in the enclosure. It is super logical, that you will get less and less SPL and efficiency as you put lesser and lesser drivers in the box. Noone expects a 3" woofer with Xmax of 3mm play as much, do we?
It's all very simple common sense, and very, VERY basic physics. No High school math, no magic. That's why it is most shocking this is somehow controversial. The same way as I described in max two sentences, that the driver that pushes the speaker cone with more Newtons surprisingly gives more SPL.
Why would it break Hoffman's iron law in any way...
Now what I and many other users do with this, is that they can pack enough SPL in their car or truck of restricted space. That means less trucks, less truck drivers, less rigging crew and other expenses for given SPL. So the higher price is returned by such savings. I put four of such beasts into medium sized european car, and serve 250 people venue. That was not possible before.
Next step is Powersoft M-Force. They went HAM on this approach.
Haha, I was only joking. I've been squeezing as much bass as possible out of every liter of volume both professionally and as a hobby for more than 30 years. I've got a pretty good idea how it works 😉
Of course hi-fi 10" driver will sound much better in the lower midrange than pro 18" woofer. 👍
On the other hand, comparing efficiencies of pro 18" woofer and hi-fi 10" woofer doesn't make sense (of course 18" will be much more efficient!). Comparing measurements of one 18" woofer to another 18" woofer should be much more meaningful.
I am glad HornResp Efficiency/1W (Acoustical Power) plot proved my analysis that efficiency SPL will show valley at tuning frequency, together with peak around the frequency of the second impedance peak - which is especially visible with the Seas 10" driver (grey curve). Efficiency SPL peak at the first impedance peak is very low, because the whole Efficiency/1W graph is shaped by the SPL vs frequency graph (not shown) which is measured with constant 2.83V - at frequency of the first impedance peak there is very low SPL. That is another way to show why we must not equalize vented box lower than tuning frequency.
What is the practical implication of this graph? Look at the 13dB (approx) difference between the valley at 25Hz (where impedance minimum is) and the peak at 46Hz (where second impedance peak is) for Seas 10" (grey curve). The real-world SPL measured with 2.83V (not shown) is flat at 46Hz and above, and only 6dB down at 30Hz. If we try to equalize this (to make perfectly flat frequency response), we must apply +6dB boost at 25Hz - but that is four times more power! In a view of 13dB difference in efficiency, we can conclude: We can not use the higher efficiency of the driver in the vicinity of the 46Hz to help to increase the SPL at 25Hz, so the DSP/IPAL equalization (which OP raved about) can not help in any meaningful way to be "more efficiency green", "low Watt/heath - high SPL", "save the Earth" and so on...
I am at the verge og hijacking this thread, but I will continue my low efficiency crusade, undiminished and proud.
Both the Seas 10" A26RE4 and Seas W26FX002 were confirmed a bit too boomy for my taste:
My ears are still ringing, so something had to be done. I epoxied some leftover tubes and voila!
I don't get to test it just yet, it is night time, but I sure am hopeful. Unless I made a huge mistake somewhere.
The W26FX002 looks great in sims with the new long tubes, so I will measure those first.
Both the Seas 10" A26RE4 and Seas W26FX002 were confirmed a bit too boomy for my taste:
My ears are still ringing, so something had to be done. I epoxied some leftover tubes and voila!
I don't get to test it just yet, it is night time, but I sure am hopeful. Unless I made a huge mistake somewhere.
The W26FX002 looks great in sims with the new long tubes, so I will measure those first.
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