I'm looking to build a compact and lightweight speaker for bass guitar and electronic drums. I'm looking for 110dB at 40Hz at 1m in 4pi space. It may be a 2 or 3 way design.
At the moment, I've modelled NE265W-04 in a 30L box tuned to 33Hz in winisd. This is giving me 108dB at 40Hz at 23.6V (150W) in winisd so 102dB in 4pi. It's a 10 inch speaker and weighs 5 lbs.
I'd like to keep the box volume about that size. And I want to keep the weight of the driver down. And the power manageable. And I need a 4 ohm speaker. And 8dB more output without throwing 8dB more power at it.
Wishful thinking or can I do any better?
Is there a way to search for drivers that will work in that size box and predict the output at 40Hz without modelling? Just something to get in the ball park so I don't have model each and every speaker? Ideally a quick glance at the ts parameters should tell me if it's suitable.
I did try sorting based on peak excursion times cone area. But that doesn't tell the whole story.
At the moment, I've modelled NE265W-04 in a 30L box tuned to 33Hz in winisd. This is giving me 108dB at 40Hz at 23.6V (150W) in winisd so 102dB in 4pi. It's a 10 inch speaker and weighs 5 lbs.
I'd like to keep the box volume about that size. And I want to keep the weight of the driver down. And the power manageable. And I need a 4 ohm speaker. And 8dB more output without throwing 8dB more power at it.
Wishful thinking or can I do any better?
Is there a way to search for drivers that will work in that size box and predict the output at 40Hz without modelling? Just something to get in the ball park so I don't have model each and every speaker? Ideally a quick glance at the ts parameters should tell me if it's suitable.
I did try sorting based on peak excursion times cone area. But that doesn't tell the whole story.
Well, assuming vented, then based on the attached chart you're limited to ~0.2 % eff. = ~105 dB/W/m/40 Hz, so looks like only another ~3 dB available.
Attachments
I'm trying to understand what you wrote:
I think there's a mistake there or I don't understand what's going on. Did you mean to say 105 dB/m/40 Hz?
The chart tickles 0.2% efficiency and the table in the link says 85dB.
The NE265W-04 plus box is modelling at 86dB at 40Hz at 1W. Which is close to 85 dB.
If I double the efficiency to 0.4% the sensitivity only increases by 3dB. Not unexpected, but that's more than double the box volume.
So I gess this is saying I can't do better in this size box? The only way to more SPL is more power or more speaker sensitivity at 40Hz?
Do you know what ts parameters affect speaker sensitivity at 40Hz?
That chart is really really helpful. Thanks for posting it.
Do other configurations (transmission lines, horns, etc) have a similar chart somewhere?
I think there's a mistake there or I don't understand what's going on. Did you mean to say 105 dB/m/40 Hz?
The chart tickles 0.2% efficiency and the table in the link says 85dB.
The NE265W-04 plus box is modelling at 86dB at 40Hz at 1W. Which is close to 85 dB.
If I double the efficiency to 0.4% the sensitivity only increases by 3dB. Not unexpected, but that's more than double the box volume.
So I gess this is saying I can't do better in this size box? The only way to more SPL is more power or more speaker sensitivity at 40Hz?
Do you know what ts parameters affect speaker sensitivity at 40Hz?
That chart is really really helpful. Thanks for posting it.
Do other configurations (transmission lines, horns, etc) have a similar chart somewhere?
I think it's wishful thinking. My 100+ liter TH has enough trouble getting that much output at 40 Hz. You might be able to get it using one of those high-Xmax drivers and a lot of power in a passive radiator alignment, but how long is that driver going to last when driven that hard...
Yes, typo, s/b 20% and so used to listing W/m that I didn't notice this typo either.
That's been my experience. 🙁
T/S math
You're welcome! Their 'over the top' quantity/quality of calculators would have taken up a lot of bookcase space where I worked.
Not that I'm aware of, or if I ever did, don't remember. 🙁
I did some playing with winisd.
30 L tuned to 33 Hz. If I double the box size a peak appears where there was none. The peak is at the tuning frequency and boosted 33Hz by 4dB. 40Hz only got 2.1dB.
30 L tuned to 40Hz. If I double the box size a peak appears where there was none. The peak is at 42Hz. 40Hz was boosted by 3.8dB.
So I'm wondering what the efficiency chart really says.
I'm not looking for a peak in the response, but I am looking for more dB and I don't expect to get it from the box.
The NE265W-04 sports 77dB at 40Hz according to the datasheet. If I start with more sensitivity at 40Hz then I should be able to hit my target with less power.
Is there an easy way to find out driver sensitivity at 40Hz? I found http://www.loudspeakerdatabase.com which helps by showing response curves and providing winisd files.
I came across the Dayton Audio UM8-22 8" which is a subwoofer. It has 82dB of sensitivity at 40Hz. It's 4 ohm too. Weight is 11.45 lbs.
When I load it into winisd and choose a vented C4 alignment, it gives me a box that is 73L and tuned to 22Hz. For the same power input I get almost 3dB less spl at 40Hz than the NE265W-04 in it's 30L box. Of course, UM8-22 is putting the NE265W-04 to shame at 20Hz as it should.
If I put the UM8-22 into a 30L box tuned for 33Hz, there wide bump in the response that brings it equal to the NE265W-04.
This seems counterintuitive to me. But it also tells me that there is a speaker design that is optimal for my desired enclosure volume.
How do I find it?
30 L tuned to 33 Hz. If I double the box size a peak appears where there was none. The peak is at the tuning frequency and boosted 33Hz by 4dB. 40Hz only got 2.1dB.
30 L tuned to 40Hz. If I double the box size a peak appears where there was none. The peak is at 42Hz. 40Hz was boosted by 3.8dB.
So I'm wondering what the efficiency chart really says.
I'm not looking for a peak in the response, but I am looking for more dB and I don't expect to get it from the box.
The NE265W-04 sports 77dB at 40Hz according to the datasheet. If I start with more sensitivity at 40Hz then I should be able to hit my target with less power.
Is there an easy way to find out driver sensitivity at 40Hz? I found http://www.loudspeakerdatabase.com which helps by showing response curves and providing winisd files.
I came across the Dayton Audio UM8-22 8" which is a subwoofer. It has 82dB of sensitivity at 40Hz. It's 4 ohm too. Weight is 11.45 lbs.
When I load it into winisd and choose a vented C4 alignment, it gives me a box that is 73L and tuned to 22Hz. For the same power input I get almost 3dB less spl at 40Hz than the NE265W-04 in it's 30L box. Of course, UM8-22 is putting the NE265W-04 to shame at 20Hz as it should.
If I put the UM8-22 into a 30L box tuned for 33Hz, there wide bump in the response that brings it equal to the NE265W-04.
This seems counterintuitive to me. But it also tells me that there is a speaker design that is optimal for my desired enclosure volume.
How do I find it?
Is there any particular reason that you chose the NE265W-04?
Also, I think with a relatively small ported box you will not actually reach the design goals under full power due to port compression and other pesky losses.
Also, I think with a relatively small ported box you will not actually reach the design goals under full power due to port compression and other pesky losses.
I just did some messing around on Hornresp. Yes, it's possible to get 110dB@40Hz in 4pi.
A pair of good 12" PA subwoofers, mounted isobaric, with PRs, will get you there. The one I simulated managed about 115dB@40Hz, and more like 113dB above 50Hz.
There's a catch, though: 500w per driver.
Chris
A pair of good 12" PA subwoofers, mounted isobaric, with PRs, will get you there. The one I simulated managed about 115dB@40Hz, and more like 113dB above 50Hz.
There's a catch, though: 500w per driver.
Chris
I started this particular journey with a target of 100dB 2pi at 40Hz. After modelling a lot of drivers in various boxes I found the HDS-P830875 got there with the least power. Well more like 98 dB. The driver is capable of 75W, but excursion is limiting overall performance.
I built this into a box and evaluated it. It's not loud enough at 40Hz.
When I started looking for a driver, I was just looking at cone area and excursion. I decided that in this box, if I ignore the obvious limits of the HDS-P830875 and find how much excursion it takes to get to 116 dB I could figure out the volume of air the driver needs to push. Based on that criteria and weight of the driver, I landed on NE265W-04.
And there's something seemingly magic about the HDS-P830875 and the NE265W-04 because out of all the drivers I played with they're making 40Hz with the least power in this box.
This may be true. I haven't even started looking at the what the required port volume is doing.
Thanks for that.
The best I've modelled so far is a Dayton UM8-22. In a 30L box tuned to 33Hz, it's doing 110dB 2pi at 40Hz at 300W.
4 of them should get to 116dB. That's 1200W total.
Yours comes in at 1000W. Seems like the trend here is that a lot of power is needed. This isn't surprising.
I'll throw another data point out there. There's a commercial design, the Alesis Strike 12. No real specs, but it says max spl is 128dB and -10dB is at 46Hz. With a gracious amount of salt, it could be doing 110dB at 40Hz. Probably not 4pi. Rear plate says 600W.
While the net volume might be 30 litres, I'll bet that the box that you'll have to build to hold that arrangement is going to be considerably larger than 30 litres...
Need to be mindful that as the peaking increases, so goes VC heat rise which equates to lowering efficiency with increasing heat rise, i.e. 'robbing Peter to pay Paul'.
It's worth noting that 115dB in 4pi = 121dB in 2pi, per the simulations.
Given that, 100W will get you 111dB@40Hz in 2pi, and the drivers will be having an easy time.
Brian's point about getting it all in 30L still stands. I used 30L as the box volume.
Chris
I appreciate the responses so far and I understand that it can be done with 30L of space in the box, but the box will be larger than 30L. The question has been about 30L of space in the box. I don't know for sure, but I'm guessing the isobaric solution requires more than 100L total.
Given my self imposed "portability constraints" 110dB in 4pi space is not gonna happen. I am intending this box to portable without a forklift. I already have a 15" bass cab that is "portable", but for all intents and purposes stays where it is. And I have no idea what spl it produces. It's loud.
So I'm still left with a question:
Is there another combination of speaker and tuning frequency that will produce more than 108dB 2pi with 150W in a 30L box?
Is there a theoretical limit that says one way or the other?
Just realising that the theoretical limit for overall sensivitiy in a 30L box at 40Hz has already been established.
So that is 85dB per W per m. Is that a 2pi or 4pi number?
The NE265W-04 in a 30L box tuned to 33Hz is modelling at 86dB at 40Hz at 1W (2pi).
Two of these drivers in the same box is worse at 40Hz no matter how I tune it, but the maximum at 40Hz 1W never goes above 85. Is that due to the 30L box volume?
This can't be entirely true because different speakers pivot about a slightly different number as I change the tuning. Though it seems to be +/- 1dB.
Chris's isobaric example is 91dB per W per m (2pi). It gains extra efficiency through the isobaric configuration?
So that is 85dB per W per m. Is that a 2pi or 4pi number?
The NE265W-04 in a 30L box tuned to 33Hz is modelling at 86dB at 40Hz at 1W (2pi).
Two of these drivers in the same box is worse at 40Hz no matter how I tune it, but the maximum at 40Hz 1W never goes above 85. Is that due to the 30L box volume?
This can't be entirely true because different speakers pivot about a slightly different number as I change the tuning. Though it seems to be +/- 1dB.
Chris's isobaric example is 91dB per W per m (2pi). It gains extra efficiency through the isobaric configuration?
Hofmann's Iron Law in full effect here - as you're finding, by changing driver complement/tuning you can find a small amount of wiggle room but not a lot.
I guess that means the 85dB/W/m is 2pi. Good to know.
I should correct the statement about 4 Dayton UM8-22 in a 30L box. They do not make any more dB at 40Hz with four in the same 30L box.
That makes Chris's isobaric simulation quite spectacular.
I should correct the statement about 4 Dayton UM8-22 in a 30L box. They do not make any more dB at 40Hz with four in the same 30L box.
That makes Chris's isobaric simulation quite spectacular.
You might find that a non-isobaric 12" will also do the job, but it'll need to be a very good driver to do it. The Beyma 12SW1300Nd springs to mind, but others are available.
If you can tell us a bit more about the 15" you've been using, that'll give us a good reference. A high-end 12" might well beat it.
Chris
If you can tell us a bit more about the 15" you've been using, that'll give us a good reference. A high-end 12" might well beat it.
Chris
That Beyma 12SW1300Nd is a nice speaker, but at 1200W it's running into excursion issues. Playing with the tuning and lowering the power I can get to 116dB at 40Hz. 1050W and 37Hz tune. 30L box.
For fun, a 6" vent is required that's 22m/s. 182.4 cm^2 port area, 121.7 cm port length, that's 22L of port. Plus 4L for the driver. Driver weighs 17.6 lb. 1st port resonance at 141Hz.
So we're up to 56L.
Now 56L might not be so bad. The driver weight is worse. Ultimately though I'd have to add another enclosure and woofer. So it's only going to get bigger and heavier.
Compared to NE265W-04 which is 106 dB at 100W at 40Hz in a 30L box tuned to 33Hz. Requires a 3.1" round vent for 22m/s. That 48.7 cm^2 of port area, 38.83cm port length and 1.8L of vent. They don't list driver displacement so I'll fudge it at 2L. Driver weighs 5lbs. 1st port resonance at 442Hz.
Combined total is 34L.
My goal was to get as much 40Hz as possible out of something portable. Mostly because the ones commercially available aren't forthcoming in their specs (at least in the music world).
And no, I don't know much about the 15". I didn't build it. Also haven't measured it.
I think I'm going to have to give up on 116dB and live with 106dB. At least it's in the ballpark of what I think an acoustic kick drum puts out.
I learned a great deal from this thread, thanks everyone for your input.
For fun, a 6" vent is required that's 22m/s. 182.4 cm^2 port area, 121.7 cm port length, that's 22L of port. Plus 4L for the driver. Driver weighs 17.6 lb. 1st port resonance at 141Hz.
So we're up to 56L.
Now 56L might not be so bad. The driver weight is worse. Ultimately though I'd have to add another enclosure and woofer. So it's only going to get bigger and heavier.
Compared to NE265W-04 which is 106 dB at 100W at 40Hz in a 30L box tuned to 33Hz. Requires a 3.1" round vent for 22m/s. That 48.7 cm^2 of port area, 38.83cm port length and 1.8L of vent. They don't list driver displacement so I'll fudge it at 2L. Driver weighs 5lbs. 1st port resonance at 442Hz.
Combined total is 34L.
My goal was to get as much 40Hz as possible out of something portable. Mostly because the ones commercially available aren't forthcoming in their specs (at least in the music world).
And no, I don't know much about the 15". I didn't build it. Also haven't measured it.
I think I'm going to have to give up on 116dB and live with 106dB. At least it's in the ballpark of what I think an acoustic kick drum puts out.
I learned a great deal from this thread, thanks everyone for your input.