Help,
am currently building a pair of pa speakers. Can find lots of calculators for box volume but very little on customizing dimentions. The sites I have found have a preset ratio of width, height and depth that is more suitable to home hifi.
any suggested sites that contain information or calculators for customizing dimentions would be of great assistance.
thanks heaps
don c
am currently building a pair of pa speakers. Can find lots of calculators for box volume but very little on customizing dimentions. The sites I have found have a preset ratio of width, height and depth that is more suitable to home hifi.
any suggested sites that contain information or calculators for customizing dimentions would be of great assistance.
thanks heaps
don c
I don't excatly know what you consider more suitable for hifi/PA, but assuming you want to minimise colouration from the enclosure by reducing overlapping standing waves, you will want to use ratios of the irregular nature.
There are many irregular ratios that you can use to spread out the standing waves. A glance at the standing waves for an enclosure based on the above ratio shows that there are no similar frequencies being excited in more than one dimension. This is typically what you're looking for.
vikash
thanks that standing wave calculator was perfect. I imagine that the aim is to make sure that there are no matching frequencies(standing waves) from any cabinet side that could cause frequency cancelation.
I dont think its too far off the thread to get feed back on a box design for the following speaker-
paudio
hp-12w
12 inch
100 watt
Fs 48hz
Re 5.5Ohm
Qms 4.99
Qes 0.65
Qts 0.57
vas 99.77 litres
Xmas 2mm
No (1.67)
Im not sure what it is about this speaker's specifications but several different calculators have come up with recommended vented box sizes around 260 litres. Thats huge. I think I'm going to break my back carrying them.
The recommended vent sizes were also large at around 15cm diameter. I tried using a 6.5 cm vent diameter(I have a couple spare) but the length came up as a negative number.
Thanks
thanks that standing wave calculator was perfect. I imagine that the aim is to make sure that there are no matching frequencies(standing waves) from any cabinet side that could cause frequency cancelation.
I dont think its too far off the thread to get feed back on a box design for the following speaker-
paudio
hp-12w
12 inch
100 watt
Fs 48hz
Re 5.5Ohm
Qms 4.99
Qes 0.65
Qts 0.57
vas 99.77 litres
Xmas 2mm
No (1.67)
Im not sure what it is about this speaker's specifications but several different calculators have come up with recommended vented box sizes around 260 litres. Thats huge. I think I'm going to break my back carrying them.
The recommended vent sizes were also large at around 15cm diameter. I tried using a 6.5 cm vent diameter(I have a couple spare) but the length came up as a negative number.
Thanks
I think the standing waves sum together causing humps in the FR.
I did a quick model of this driver and it does appear to require a large enclosure. Unibox shows an optimum vented enclosure of 321 Litres for an F3 of 29Hz. However, you're also looking at a max of 97db and <90db at ~2W input before you've run out of xmax at f3.
Halving the enclosure volume results in only a slighly higher f3 (40Hz) with a 0.12 ripple. It seems the larger cabinet is not worth its weight.
I would reccomend using Unibox above all other (free) modellers.
Vikash unibox is great. Much more powerful than the other calculators that i was using. Still working out some parameters such as absorption Qa, Leakage Ql and port Qp. If you know of any sources or further discussions on the net with more detail on port air speed, cone excursion, speaker impedance and the other unibox graphs and what effect they have on design it would be great. I have played with Unibox for a while and got down to a 96 litre box with a f3 of 44hz(using Fb of 40). Thats a much lighter box than I started with.
GM thanks for your comments. I ran your figures on unibox and came up with an F3 of 58.61hz. This box would be ideal for a vocal PA and easy to lift. I will need the PA to go lower than this for backing music. This design might best match with a sub with a 60hz crossover for the kick drum and bass in the backing.
Im starting to warm to the golden ratio but Im use to PA speakers with a greater depth to side ratio than 0.6:1. I wonder if it affects the sound if the speakers are mounted on the narrow side(assuming there is enough room).
Thanks again
don c
GM thanks for your comments. I ran your figures on unibox and came up with an F3 of 58.61hz. This box would be ideal for a vocal PA and easy to lift. I will need the PA to go lower than this for backing music. This design might best match with a sub with a 60hz crossover for the kick drum and bass in the backing.
Im starting to warm to the golden ratio but Im use to PA speakers with a greater depth to side ratio than 0.6:1. I wonder if it affects the sound if the speakers are mounted on the narrow side(assuming there is enough room).
Thanks again
don c
>GM thanks for your comments. I ran your figures on unibox and came up with an F3 of 58.61hz. This box would be ideal for a vocal PA and easy to lift. I will need the PA to go lower than this for backing music. This design might best match with a sub with a 60hz crossover for the kick drum and bass in the backing.
====
You're welcome! This driver can't handle much SPL down low (let the excursion plot be your guide as to how low you can go), so yeah, a high power/excursion sub will be required if you need a lower F3.
====
>Im starting to warm to the golden ratio but Im use to PA speakers with a greater depth to side ratio than 0.6:1. I wonder if it affects the sound if the speakers are mounted on the narrow side(assuming there is enough room).
====
It raises the baffle step, but I assume you EQ the system with at least a 1/6 octave selectivity for each venue, so it's moot. FYI, there are many other suitable acoustic ratios. Design your cab, then use a room mode calculator to see how it fares, and adjust as required.
GM
====
You're welcome! This driver can't handle much SPL down low (let the excursion plot be your guide as to how low you can go), so yeah, a high power/excursion sub will be required if you need a lower F3.
====
>Im starting to warm to the golden ratio but Im use to PA speakers with a greater depth to side ratio than 0.6:1. I wonder if it affects the sound if the speakers are mounted on the narrow side(assuming there is enough room).
====
It raises the baffle step, but I assume you EQ the system with at least a 1/6 octave selectivity for each venue, so it's moot. FYI, there are many other suitable acoustic ratios. Design your cab, then use a room mode calculator to see how it fares, and adjust as required.
GM
Well I built one box 96L as a compomise with an 11cm diameter port and it sounds good in the middle but is completely lacking in any bottom end. It cuts of much higher than expected in the bottom end(above 100hz perhaps). Will be getting a graphic to check this latter on. It could be the speaker, my box or as you suggested GM, the published parameters that I did the calculations from.
I think I will put them into that smaller box you suggested GM and build a sub. Hey Ive got another speaker from the same company that I have been looking at E12-200s. Check out the specs below-
fs 59.7
Re 5.7
Qms 9.43
Qes 0.5
Qts 0.48
Vas 49.06
Xmax 3.5
all in metric
These seem much more suited to a small enclosure.
Any comments?
I think I will put them into that smaller box you suggested GM and build a sub. Hey Ive got another speaker from the same company that I have been looking at E12-200s. Check out the specs below-
fs 59.7
Re 5.7
Qms 9.43
Qes 0.5
Qts 0.48
Vas 49.06
Xmax 3.5
all in metric
These seem much more suited to a small enclosure.
Any comments?
>Well I built one box 96L as a compomise with an 11cm diameter port and it sounds good in the middle but is completely lacking in any bottom end. It cuts of much higher than expected in the bottom end(above 100hz perhaps). Will be getting a graphic to check this latter on. It could be the speaker, my box or as you suggested GM, the published parameters that I did the calculations from.
====
Hmm, it should have a ~40Hz F3 depending on how long the vent is. You are aware that the sim is half space and that any speaker will need 3-6dB of baffle step compensation, right? Of course make sure there's no leaks, it doesn't take much to kill the vent action.
====
>I think I will put them into that smaller box you suggested GM and build a sub.
====
I would if relatively low distortion is required.
====
>Hey Ive got another speaker from the same company that I have been looking at E12-200s.
>These seem much more suited to a small enclosure.
Any comments?
====
Yes, the cab's much smaller, but the tradeoff is less output below ~125Hz in a Pi Alignment. The E12 is marginally more efficient above this point though.
GM
====
Hmm, it should have a ~40Hz F3 depending on how long the vent is. You are aware that the sim is half space and that any speaker will need 3-6dB of baffle step compensation, right? Of course make sure there's no leaks, it doesn't take much to kill the vent action.
====
>I think I will put them into that smaller box you suggested GM and build a sub.
====
I would if relatively low distortion is required.
====
>Hey Ive got another speaker from the same company that I have been looking at E12-200s.
>These seem much more suited to a small enclosure.
Any comments?
====
Yes, the cab's much smaller, but the tradeoff is less output below ~125Hz in a Pi Alignment. The E12 is marginally more efficient above this point though.
GM
Vikash said:
Hi,
I am a relatively new DIY er and am working on my first Floorstander speaker design.
I am confised on the Dimension ration I have been seeing all around.
I tried out the calculator mentioned in your post. But I am unable to figure our how to interpret the results ..whether they are good or bad.
Kindly let me know how I can use this tool.
And in addition, I am posting my dimension results from the calculator below:
Could you let me know if the dimensions are ok? This is for a 8inch driver.
H= 1041mm W = 254mm D= 305mm
Results:
Height Width Depth
165 Hz 675 Hz 564 Hz_
329 Hz 1.35 KHz 1.13 KHz_
494 Hz 2.03 KHz 1.69 KHz_
659 Hz 2.70 KHz 2.26 KHz_
824 Hz 3.38 KHz 2.82 KHz_
988 Hz 4.05 KHz 3.38 KHz_
1.15 KHz 4.73 KHz 3.95 KHz_
1.32 KHz 5.40 KHz 4.51 KHz_
Thansk in advance for your help.
Regards,
Linoj.
Vikash said:
Hi,
I am a relatively new DIY er and am working on my first Floorstander speaker design.
I am confised on the Dimension ration I have been seeing all around.
I tried out the calculator mentioned in your post. But I am unable to figure our how to interpret the results ..whether they are good or bad.
Kindly let me know how I can use this tool.
And in addition, I am posting my dimension results from the calculator below:
Could you let me know if the dimensions are ok? This is for a 8inch driver.
H= 1041mm W = 254mm D= 305mm
Results:
Height Width Depth
165 Hz 675 Hz 564 Hz_
329 Hz 1.35 KHz 1.13 KHz_
494 Hz 2.03 KHz 1.69 KHz_
659 Hz 2.70 KHz 2.26 KHz_
824 Hz 3.38 KHz 2.82 KHz_
988 Hz 4.05 KHz 3.38 KHz_
1.15 KHz 4.73 KHz 3.95 KHz_
1.32 KHz 5.40 KHz 4.51 KHz_
Thansk in advance for your help.
Regards,
Linoj.
You want to make sure none of the numbers are the same (or close) and if they are, then it's better that the clashing modes are of a higer order.
i.e width mode 5 and depth mode 6 are similar, but higher modes are attenuated and in this instance it probably isn't something to worry about. Stuffing the enclosure appropriately will attenuate them further as well.
Your bracing strategy will also alter/break up standing waves, so I woudn't put too much weight on that calculator alone. You dimensions seem acceptble to me at the lower modes, which is what's important I think.
Thank you for validating...
Now I have a second question on the basic construction of the enclosure.
As posted earlier, my box dimensions are 42.5X11.5X13.5( HXWXD) inches
My doubt here is how the corners of the box should be joined. I read somewhere that the corners can be cut at 45 degree angle and pasted and Nailed.
The other joint was kind of inter tangled between the joining edges.COuld anyone tell me how the correct box corner joints shud be made.
And the next question if of more importance:
For the front and Back baffle, how should it be fixed. Should it be fixed such that it lies ON all four edges , or should it be fixed within the 4 edges
Now I have a second question on the basic construction of the enclosure.
As posted earlier, my box dimensions are 42.5X11.5X13.5( HXWXD) inches
My doubt here is how the corners of the box should be joined. I read somewhere that the corners can be cut at 45 degree angle and pasted and Nailed.
The other joint was kind of inter tangled between the joining edges.COuld anyone tell me how the correct box corner joints shud be made.
And the next question if of more importance:
For the front and Back baffle, how should it be fixed. Should it be fixed such that it lies ON all four edges , or should it be fixed within the 4 edges
GM said:
GM the vent diameter for this box is an odd size. Is their a vent calculator that I could use that could recalculate the length of the vent above for different diameters? eg for 8 or 10 cm pipes
GM said:
No I didnt realize. what does this mean?
I think I need to do some serious reading. Any good books that you would suggest to get me up to speed with this would be good. I find that many of the discussions in the forum are a level above my understanding at the moment.
thanks again
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