From here: http://www.diyaudio.com/forums/multi-way/216074-ideas-avant-garde-trio-clone.html
I have been working on a 3 way front loaded horn setup, It is all designed and sent off to the CNC shop to be machined. While that is being done, I thought I may as well build some subs to keep up.
I have no preference for any type of enclosure, all I need is it to be fairly efficient, with usability from at least 30hz to 100hz, with a maximum output of about 130-135db across this range without reaching mechanical limits.
There are some limitations. I don't want to spend more than about $1000 in drivers, being in Australia, this makes things a bit difficult. There are local dealers for Eminence, Celestion, B & C and 18 Sound. if a pro sound driver in the US is about $300, it will be about $500 here. The only half decent looking 18 inch driver I can get from 18 Sound is the 18LW2400, however I have found it doesn't model very well in either or Josh Ricci's designs and Xoc1's design doesn't extend low enough.
Alternatively I can get 4 12 inch Peerless XLS or XXLS [830500 or 835017] or 6 of the 10s locally for that price.
I have been looking at tapped horns, as a horn loaded sub would go well with the rest of the system, however I cannot find a design that will give me the bandwidth I desire, using a pair of drivers that are readily available to me here.
Any ideas, links to threads,etc will be much appreciated.
Ryan
I have been working on a 3 way front loaded horn setup, It is all designed and sent off to the CNC shop to be machined. While that is being done, I thought I may as well build some subs to keep up.
I have no preference for any type of enclosure, all I need is it to be fairly efficient, with usability from at least 30hz to 100hz, with a maximum output of about 130-135db across this range without reaching mechanical limits.
There are some limitations. I don't want to spend more than about $1000 in drivers, being in Australia, this makes things a bit difficult. There are local dealers for Eminence, Celestion, B & C and 18 Sound. if a pro sound driver in the US is about $300, it will be about $500 here. The only half decent looking 18 inch driver I can get from 18 Sound is the 18LW2400, however I have found it doesn't model very well in either or Josh Ricci's designs and Xoc1's design doesn't extend low enough.
Alternatively I can get 4 12 inch Peerless XLS or XXLS [830500 or 835017] or 6 of the 10s locally for that price.
I have been looking at tapped horns, as a horn loaded sub would go well with the rest of the system, however I cannot find a design that will give me the bandwidth I desire, using a pair of drivers that are readily available to me here.
Any ideas, links to threads,etc will be much appreciated.
Ryan
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Hi More10,
I can probably stretch the budget a little bit to be able to purchase 4 of the 15W700, those sims look about perfect for what I am after, I shall email the company and hopefully get a reply back Monday.
And djn, I have spent a bit of time on William's site, it is what made me suggest the possibility of using the Peerless drivers, thank you.
I can probably stretch the budget a little bit to be able to purchase 4 of the 15W700, those sims look about perfect for what I am after, I shall email the company and hopefully get a reply back Monday.
And djn, I have spent a bit of time on William's site, it is what made me suggest the possibility of using the Peerless drivers, thank you.
Hi Djim,
Any reason as to why the 15W700 doesn't suit? I had a quick model of it last night and it didn't look that bad, however it was very late last night (early morning) and I only had a brief look.
If you have any other ideas for suggestions of drivers and enclosures, that would be appreciated.
Thanks,
Ryan.
Any reason as to why the 15W700 doesn't suit? I had a quick model of it last night and it didn't look that bad, however it was very late last night (early morning) and I only had a brief look.
If you have any other ideas for suggestions of drivers and enclosures, that would be appreciated.
Thanks,
Ryan.
Hi ryzaa,
First of all, there is nothing wrong with the design of more10.
But... 🙂.... there are a few things to consider when you want to compare its model. There seems to be a 5Hz difference in low corner between model and measurement but in favour of the model. The sim is modelled in 0.5 Pi (?) while his measurements seem to be done in 1Pi and within the so called 'horn bubble'.
The models which you compared (Cox1-TH18 and Josh Ricci's design) are modelled in 2 Pi and actual measurements show very similar results. In other words, if you compare more10’s design with other designs make sure you compare with a correct model and on equal base.
Driver may shine in sims but it doesn’t tell you anything about its physical capabilities, thermal compression losses and so on. The 15W700 is not built for low tuned horns and 18Sound marks it not for nothing as a "compact reflex driver". If you look at the Thiele-Small parameters it also shows it is not designed for low tuned horns. The first 18Sound that could qualify for more10’s design is something like the new 15W930.
It looks like there is a Neodymium alternative available in your country for about $279, the Ande AN-15C Neodymium driver. Although Ande drivers have a good reputation the published Xmax looks more like a Xvar🙁.
There might be cheaper alternatives depending on the use for your bass bins (PA, indoors/outdoors, hifi?) and how you are going to drive them (what amp, active ect). So a little more info about their task would be welcome...🙂
First of all, there is nothing wrong with the design of more10.
But... 🙂.... there are a few things to consider when you want to compare its model. There seems to be a 5Hz difference in low corner between model and measurement but in favour of the model. The sim is modelled in 0.5 Pi (?) while his measurements seem to be done in 1Pi and within the so called 'horn bubble'.
The models which you compared (Cox1-TH18 and Josh Ricci's design) are modelled in 2 Pi and actual measurements show very similar results. In other words, if you compare more10’s design with other designs make sure you compare with a correct model and on equal base.
Driver may shine in sims but it doesn’t tell you anything about its physical capabilities, thermal compression losses and so on. The 15W700 is not built for low tuned horns and 18Sound marks it not for nothing as a "compact reflex driver". If you look at the Thiele-Small parameters it also shows it is not designed for low tuned horns. The first 18Sound that could qualify for more10’s design is something like the new 15W930.
It looks like there is a Neodymium alternative available in your country for about $279, the Ande AN-15C Neodymium driver. Although Ande drivers have a good reputation the published Xmax looks more like a Xvar🙁.
There might be cheaper alternatives depending on the use for your bass bins (PA, indoors/outdoors, hifi?) and how you are going to drive them (what amp, active ect). So a little more info about their task would be welcome...🙂
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The simulation is done in 2 pi, as the measurement.
Simulation of 15W930 in 2pi. I wouldn't put that driver in my box
An externally hosted image should be here but it was not working when we last tested it.
Simulation of 15W930 in 2pi. I wouldn't put that driver in my box
These will be active, off a couple 500wrms amps. They will be first used outdoors, but will primarily be used indoors, with the occasional venture out. A lot of the music they will be playing does extend into the low 20's.
When I simulated the 15W700, I was doing it into 2pi, as I know these will be used outdoors a bit.
Unfortunately the 15W930 retails for about $600 here, without shipping and the like. Whatever design I end up going with, another local guy may consider doing also, who needs it for fairly similar uses. That being the case, we may combine shipping and the like to try and save a little bit more.
Thanks for the help and suggestion,
Ryan.
When I simulated the 15W700, I was doing it into 2pi, as I know these will be used outdoors a bit.
Unfortunately the 15W930 retails for about $600 here, without shipping and the like. Whatever design I end up going with, another local guy may consider doing also, who needs it for fairly similar uses. That being the case, we may combine shipping and the like to try and save a little bit more.
Thanks for the help and suggestion,
Ryan.
Hi ryzaa,
Okay, so basically you want two or four PA subs with extended low frequency range, a total output of > 130dB and driven by two 500 Watt amps. They are going to be used for in-and-outdoor events and the drivers have a limited budget of $1000 total. A few questions;
1. Is the 500 watt amp power rated at 8 Ohm or 4 Ohm?
2. Is there a size/weight limit for the enclosures?
3. What is the crossover frequency?
If a driver sims very well in a certain PA horn design, it is not a guarantee it actually is a good PA horn driver. If you don’t know how to recognise them, check first the manufacturer’s website and see what they recommend. Secondly, check the web and see if any Pro PA manufacturer uses the same driver for a similar bass horn task.
About the loss-factors, sims don’t suffer from it but in reality all our cabs do. What that means is that when you have a sensitivity of 100dB from 1w/1m, the theoretical modelled output with 500 watts is 127dB. In reality however, the output can be significant lower. The losses are completely transferred into heat, so called Thermal compression. That is what most drivers kills in PA cabs.
An old rule of thumb for horns is that the weaker the motor force (BL) the higher the losses at high levels (that also counts for tapped horns). It’s therefore important to realise that sims/models and low level measurements only show what happens at low signals while PA bass horns need to have the best performance at high levels. In other words, judging PA designs purely on sims or low level measurements can be very misleading!
Okay, so basically you want two or four PA subs with extended low frequency range, a total output of > 130dB and driven by two 500 Watt amps. They are going to be used for in-and-outdoor events and the drivers have a limited budget of $1000 total. A few questions;
1. Is the 500 watt amp power rated at 8 Ohm or 4 Ohm?
2. Is there a size/weight limit for the enclosures?
3. What is the crossover frequency?
If a driver sims very well in a certain PA horn design, it is not a guarantee it actually is a good PA horn driver. If you don’t know how to recognise them, check first the manufacturer’s website and see what they recommend. Secondly, check the web and see if any Pro PA manufacturer uses the same driver for a similar bass horn task.
About the loss-factors, sims don’t suffer from it but in reality all our cabs do. What that means is that when you have a sensitivity of 100dB from 1w/1m, the theoretical modelled output with 500 watts is 127dB. In reality however, the output can be significant lower. The losses are completely transferred into heat, so called Thermal compression. That is what most drivers kills in PA cabs.
An old rule of thumb for horns is that the weaker the motor force (BL) the higher the losses at high levels (that also counts for tapped horns). It’s therefore important to realise that sims/models and low level measurements only show what happens at low signals while PA bass horns need to have the best performance at high levels. In other words, judging PA designs purely on sims or low level measurements can be very misleading!
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Hi ryzaa,
Post #1: "...usability from at least 30hz to 100hz, with a maximum output of about 130-135db across this range..."
Post #10: "...will be first used outdoors, but will primarily be used indoors...A lot of the music they will be playing does extend into the low 20's."
I may not be apparent, but the "low 20s" is a whole different kettle of fish than 30Hz, a FLH that can reach that low will be huge, so will a TH. Maybe give bjorno's T-TQWT a look, using dual Ande LB1560 drivers: JDs Sound and Lighting. Ande LB1560 15" 600W 8 ohm driver / speaker . If you build two of those you'll have some money left over for the wood and stuff after buying the drivers. They'll still be big and heavy, but at least they'll be portable 🙂.
Regards,
Post #1: "...usability from at least 30hz to 100hz, with a maximum output of about 130-135db across this range..."
Post #10: "...will be first used outdoors, but will primarily be used indoors...A lot of the music they will be playing does extend into the low 20's."
I may not be apparent, but the "low 20s" is a whole different kettle of fish than 30Hz, a FLH that can reach that low will be huge, so will a TH. Maybe give bjorno's T-TQWT a look, using dual Ande LB1560 drivers: JDs Sound and Lighting. Ande LB1560 15" 600W 8 ohm driver / speaker . If you build two of those you'll have some money left over for the wood and stuff after buying the drivers. They'll still be big and heavy, but at least they'll be portable 🙂.
Regards,
Attachments
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Comparing 15W700 with 15W930 4 boxes in 2 pi driven by 1000W. 15W700 in black, 15w930 in grey.
I guess both will work.
From 15W700 spec:
From 15W930:
There is a 0,4 dB difference in power compression at -3 dB (half power ~ 250 W). What will 0,4 dB difference do in the real world?
An externally hosted image should be here but it was not working when we last tested it.
I guess both will work.
From 15W700 spec:
From 15W930:
There is a 0,4 dB difference in power compression at -3 dB (half power ~ 250 W). What will 0,4 dB difference do in the real world?
Hi more10,
The Power compression figures published by manufacturers need to seen in the context of their measurement. These figures from 18Sound are not taken from horns and that makes a big difference.
To be more exact, these are based on an output measurement from a pink noise signal with a crest factor (6dB), from 50-500Hz, over a time period of 5 minutes, in a reflex enclosure of 125 Litres, tuned at 50Hz. After that measurement the output is compared with the theoretical calculated output. The difference between them is the published power compression figure. In other words, these are power compression figures from a specific load, a reflex box with a specific tuning just to give you an indication. The same driver will show very different results in a basshorn or Tapped Horn.
Maybe it’s better to use the EBP (Fs divided by Qes). An EBP value around 100 is considered optimal for basreflex enclosures and an EBP above 120 for horn drivers. The lower the tuning frequency of a basshorn the higher EPB is needed.
The EBP indicates that the higher the Fs, the better. For horns in general this is correct but it is different for low tuned basshorns. This may sound like a contradiction but a low Fs is usually a sign of a higher moving mass (Mms) that is needed to give the cone enough strength/stiffness. A higher mass can be compensated by a stronger motor force (BL).
The EBP also shows the importance of a low Qes (Electrical Suspension). More specific, a value between 0.2 and 0.3 for horns in general. The lower the tuning of a basshorn, the lower Qes is needed. A low Qes means the driver has a lot of motor force to move the cone. A high Qes is a sign of weak motor force that results in more power compression losses and maybe even more important a sooner loss of control over the excursion!
High Xmax is needed to generate enough sound pressure for high output levels but also needs a more advanced suspension to prevent mechanical suspension losses. The mechanical suspension losses can be found in the Qms value (Mechanical Suspension). The higher the Qms value, the lower the mechanical losses of the suspension.
But this still doesn’t explain why a heavier moving mass is preferred in low tuned basshorns while EBP shows the opposite. At high pressure levels the capacitive resistance (the lower the frequency the higher the resistance) of the air load in a loudspeaker enclosure can become high enough to prevent a relative lightweight cone and/or relative weak motor, from moving linear. Instead, the energy is transferred into heat and/or uncontrolled peaks in excursion (nonlinear movement). Both effects cause thermal and dynamic power compression or worse, the loss of control over the excursion. Also lightweight cones will tend to deform which increases the nonlinear behaviour. To prevent deformation of the cone it needs to be reinforced (with carbon fibres for instance). Reinforcing a cone automatically leads to more moving mass which results in a lower Fs. The heavier mass can be compensated by an even stronger motor force. There is one minor downside as result of a heavier moving mass, a slightly lower sensitivity figure. Of course, the disadvantage of a slightly lower sensitivity figure doesn’t weight against the advantage of a stronger cone that moves more linear.
Decennia’s ago RCF decided to qualify this kind of drivers as so called 'Extended Low Frequency Transducer'. More conventional drivers were qualified as 'Low Frequency Transducers'. Today 18Sound also uses the same qualification for their drivers.
15W700 = Low Frequency Transducer
15W930 = Extended Low Frequency Transducer
15W700.................... 15W930..................... 2226H
Fs = 38 Hz.................. Fs = 33 Hz................... Fs = 40 Hz
Qms = 3.8...................Qms = 8.78 ................. Qms = 5.0
Qes = 0.33..................Qes = 0.23................... Qes = 0.33
BL = 18.4....................BL = 22.1..................... BL = 19.2
EBP = 115.................. EBP = 143.................... EBP = 121
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Hello
I don't understand how Troel gets such a big rectangular vent on the Loudpeakers 3
I can't find it on winisd in 125 liters
I just use winisd and try to determine the site of rectangular port for 15w700 in 125 liters F3=40hz
Sebas, check the dimensions in the plans, I'm pretty sure that the net internal volume is rather lower than 125L, maybe around 95-100 after allowing for the drivers, bracing, port etc.
Also, I'm pretty sure it'll be tuned lower than 40Hz - try to match the shape of the roloff in Troels' graph and i think you'll end up with a tuning nearer 30Hz.
He did say in the write up that he got an in-room f3 of around 30Hz with EQ, and if that involved boosting anything down low then excursion would be excessive with a higher tuning.
Both of those factors result in needing a longer port, so I don't think his stated port length is unreasonable.
Also, I'm pretty sure it'll be tuned lower than 40Hz - try to match the shape of the roloff in Troels' graph and i think you'll end up with a tuning nearer 30Hz.
He did say in the write up that he got an in-room f3 of around 30Hz with EQ, and if that involved boosting anything down low then excursion would be excessive with a higher tuning.
Both of those factors result in needing a longer port, so I don't think his stated port length is unreasonable.