Best design for little PA sub with Wavecor SW310WA01

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#3
I wouldn't suggest these drivers for pa use, the fs is to low, and qts borderline to high for horn or tapped horn. Power handeling and sensitivity are too low for sealed to be loud enough, and vas and fs are too low for ported in pa use.

Their best use would be as sealed or ported bass drivers in tower speakers for home audio with a low tuning.

A good design starts with a driver well suited for the task, finding the perfect driver is more than half of the job of designing a speaker. You can force them into a different role, and I understand why you want to. They are what you have, and a pa sub is what you need, however I don't think that you would satisfied with the results in the long term.

Can I ask what type of music, or instuments they will be used for?
 
#4
I'll second that. The parameters are not ideal, but I understand you already have them in your posession.

Give us an idea of exactly how big you are willing to live with for the boxes. Either in total volume or dimension constraints and we'll have something to work with. "Not too big" can mean a lot of different things to different people, and size strongly dictates what designs will work and which ones won't.
 
#6
Size matters

Hi

Well I was thinking something like 60 to 70 liters for each box. 4 boxes.

I know that they are not ideally suited for PA.

But I allready have them, bought for a different project.

It is a little bit hard for me to understand to understand why they do not work for what I want. If you want to play loud in at 35 hz you need to move air. No PA woofer moves this much air. And maybe a 12 PA woofer can handle more power, but these wavecor run out of Xmax before they reach their power limit.

Is it because there Xdamage is lower than a PA woofer or their suspension is too linear and they will bottom out without warning or why?

They will play with a top with a Monacor 10/250PRO 10" and a Monacor MDH152 mid/high compressor/horn

I will run them with this amp, wich has DSP https://www.thomann.de/dk/samson_sxd5000.htm?ref=search_rslt_samson+5000_307430_0

Best regard

uwe
 
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#7
Those drivers are designed to play low, PA drivers are designed to be loud. If you want loud speakers (see what I did there?) it's sometimes easier to make them efficient. Making some 12" drivers with an Fs of 40 Hz and a Qts of 0.3 will make them +6 dB more efficient, not at 35 Hz but most energy is generally found at 63 Hz and there they'll fair better.

A single 12" like that versus one of your 12" drivers would need 4 times less power to reach a certain SPL. Now if you could give those drivers four times as much power, it could even out but those drivers don't handle a lot of power. Many PA-drivers don't have a lot of Xmax but do have a large coil, so they handle more power.

Having said that, I think 4 of your drivers are a good match for the tops that you've got. They would probably lack at higher volumes for regular PA tops but for your setup you're good to go. I'd probably go for 60 - 100 litre tuned to 30 - 35 Hz.
 
#9
Hi heinz1964,

Rademakers is correct: "...Those drivers are designed to play low, PA drivers are designed to be loud...". They'll go to 20Hz pretty easily. 🙂

I did a quick simulation in Hornresp using Vrc(internal net volume)=100L w/ a 6"I.D. duct x 20"long. That results is a SPL curve w/ a low peak which can be easily tamed w/ a second order HP filter, the other effect of the HP filter is that it controls excursion, so you can crank up the overall power a bit, and still stay below Xmax and have a low enough port particle velocity.

You can play around w/ the volume/duct/filter values, and see what kind of a response might look promising. I'll attach the Hornresp Export and some graphs.

Regards,
 

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#10
heinz1964 said:
Hi

What about Xmax. At low frequencies it has to be Xmax that is the limiting factor. Unless you don't care about distortion.

Best regards

Uwe
Click to expand...

Displacement, not xmax. That is why multiple larger cones 15-18 are most common pa bass drivers, they have as much or more displacement as smaller drivers with larger xmax, without the loss of sensitivity that comes with higher xmax. When you get to the higher power drivers around 1000w or so you are pushing a large paper cone with 11 or so mm of travel. Generally distortion takes a back seat to volume in PA systems. PA is all about getting as much spl out of the almost always limited amount of power you have at hand, without sounding horrid.

Your saving grace in this situation is that you have four of the drivers, your four 12" drivers will have only a little bit less cone area than a single 18" driver.

You can make a nice sounding subwoofer for sure with them, with less distortion than a typical pa sub, however it won't be the most bang for your wattage dollar, and your bandwidth will extend lower than you need it to. In box design you can extract more sensitivity by reducing bandwidth, however shifting that range around leads to peaky or chaotic response.

A lower tuned sub however can be useful and a dramatic sonic improvement for a few instuments, namely piano, keyboard and synth.
 
#11
heinz1964 said:
Hi

What about Xmax. At low frequencies it has to be Xmax that is the limiting factor. Unless you don't care about distortion.

Best regards

Uwe
Click to expand...

Xmax is needed to go low. 12" PA subs will often stop at 50Hz, or maybe higher. At those frequencies, thermal power handling is more important than mechanical.

As a correction to the above post, a typical 12" driver has an Sd of around 520 cm^2, and an 18" around 1100cm^2. 2x12" is pretty much equal to 1x 18", so a group of four of these woofers ought to keep up with a 2x18" cab at the bottom end (where displacement rules), but will probably lose higher up, where the sensitivity and power handling of the 2x18" will win out.

Chris
 
#12
I'd definitely go for 6th order bandpass. I've attached my design. I inflated your enclosure size by a bit, but I think that'll give you the best results. It gets a bit port chuffy, but only at the extreme ends of the bandwidth at full power and using the filters like I've shown should mostly eliminate it. Xmax and Pmax are both maximized.

First pic is a group of 4 at full power. It'll theoretically hit 130db in-band, which to me qualifies as some real PA bass. I'm guessing a group of 4 will give a JBL SRX728s at full power a run for its money if not beat it, especially at the lower end of the band.
 

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#13
chris661 said:
Xmax is needed to go low. 12" PA subs will often stop at 50Hz, or maybe higher. At those frequencies, thermal power handling is more important than mechanical.

As a correction to the above post, a typical 12" driver has an Sd of around 520 cm^2, and an 18" around 1100cm^2. 2x12" is pretty much equal to 1x 18", so a group of four of these woofers ought to keep up with a 2x18" cab at the bottom end (where displacement rules), but will probably lose higher up, where the sensitivity and power handling of the 2x18" will win out.

Chris
Click to expand...

Your right to correct me, I check on parts express as a quick sd reference, I think that I clicked on the wrong driver. I should spotted that.
 
#14
6. order

Hi guys

Thanks a lot for the help.

6. order is that a band pass subwoofer. You can not see the woofer but there is a volume and a tube/port on each side of the woofer with different tuning?

As for amp power, it is not as expensive anymore as when I was a young man and with only pocketmoney to spent 😀 (in 1984 2x180 watt was like 3000$, Rodec Discomax)

I will have a closer look at that 6. order and see how the increased volume will look dimension wise. I will use them for a mobile disco. And the cars in Denmark a smaller and way more expensive🙁.

Best regards

Uwe
 
#16
zettairyouiki said:
I think I managed to shrink it to the 70L you requested without making too many sacrifices. The port velocity isn't as much of a problem as I thought for some reason. Unfiltered response with 4 speakers shown.
Click to expand...

You can probably save a bit more volume by making this a series-tuned 6th order system. But 130dB out of 4 70L boxes? Hmm..

I managed to come up with a FLH design for this driver that hits about 95~100dB in its passband, but it requires a 200L net box...
 
#18
6th order BP is a good way of getting the top-end efficiency up. Has anyone tried a slot-loaded ported box instead? - it'd shrink one of the chambers, though the bump in sensitivity might end up >100Hz.
Worth a try, though.

When it comes to making the cabinet, I'd try to make sure that one of the ports is pointing directly at the magnet of the driver. That should help thermal power handling (which is what they're short of).

Chris
 
#19
Cooling

Hi Chris

Yes I thougth that having the air moving around the magnet would help cool the voicecoil a little.

I am not familiar with hornresponse, where do I see the volume of the two chambers and the dimensions of the tubes?

Best regards

Uwe
 
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