These are not drivers from a trading manufacturer but ones from a manufacturer that ceased trading a few years ago. Can someone correct me if I am wrong but I believe the arrangement is something like the chap from diysoundgroup has the relevant permissions to pay for a new batch to be run off by whoever has the tooling if and when he wants some more. I would strongly suggest contacting him to see if he has paid for a new batch to be run off. If he is still waiting to judge demand before forking out I would suggest looking at other drivers.
15 litres with 40 Hz tuning might be preferable but it is in the same ballpark. A concern is that the efficiency has dropped pretty low in order to get the low frequency extension in a reasonably sized box. This means an inefficient speaker, a powerful amplifier to play loud enough and a midrange and tweeter with sufficient power handling to keep up. One benefit is that the midrange would not need to be particularly efficient if a fair amount of baffle step correction is incorporated.
Ideally you probably want the amp to be able to deliver a bit more peak power than the power handling of the drivers. This keeps things clean at higher SPLs but at the risk of damage at parties. 400W woofer power handling with 30W midrange power handling is unbalanced. For music there is typically a few dB less power in the midrange passband compared to the woofer passband. So the midrange drivers power handling doesn't need to match that of the woofers. 50% is fine, 25% probably OK but 10% is too low and will become what limits the power handling of the overall speaker.
So, here goes -
40l tall bass reflex approx h1000mm x w230mm x d300mm, 18 or 22mdf with 28 or 40mm butchers block baffle.
Twin anarchy 708 6.5” woofers - power is 100w rms, 200w max, spl 85db each > 4ohm in parallel to 88db, Xmax +/- 12.5mm (back up TB W6-1339 but has less extension into higher frequencies)
Morel EM1308 2” done mid or MDM55 - power is 200w, spl 88db
Neo cd3.0 ribbon tweeter - power is 17w rms, 40w max, 93db - is this a concern, fall back is either sb26adc metal dome (power is 120w rms, 90db) or 21 or 29rdc ring domes.
Crossovers around 400hz and 4000hz +/-15%.
Hypex 3 way amps come in two sizes
FA123 is 125w x 2 plus 100w tweeter into 4ohms
FA253 is 250w x 2 plus 100w tweeter into 4 ohms
I guess the FA123 would be ok but the FA253 for the extra £100 each may give a bit of headroom.
Will try and trace the various measurements and try and model.
Many thanks for everyone’s help on this, I am clearer as to the direction of travel rather than going in ever decreasing circles up my own backside.
40l tall bass reflex approx h1000mm x w230mm x d300mm, 18 or 22mdf with 28 or 40mm butchers block baffle.
Twin anarchy 708 6.5” woofers - power is 100w rms, 200w max, spl 85db each > 4ohm in parallel to 88db, Xmax +/- 12.5mm (back up TB W6-1339 but has less extension into higher frequencies)
Morel EM1308 2” done mid or MDM55 - power is 200w, spl 88db
Neo cd3.0 ribbon tweeter - power is 17w rms, 40w max, 93db - is this a concern, fall back is either sb26adc metal dome (power is 120w rms, 90db) or 21 or 29rdc ring domes.
Crossovers around 400hz and 4000hz +/-15%.
Hypex 3 way amps come in two sizes
FA123 is 125w x 2 plus 100w tweeter into 4ohms
FA253 is 250w x 2 plus 100w tweeter into 4 ohms
I guess the FA123 would be ok but the FA253 for the extra £100 each may give a bit of headroom.
Will try and trace the various measurements and try and model.
Many thanks for everyone’s help on this, I am clearer as to the direction of travel rather than going in ever decreasing circles up my own backside.
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A narrow baffle with a transition between uniform radiation to forward beaming at a fairly high frequency. How much baffle step correction do you intend to start with and how are you going to implement it?
Your woofers and amp will give a maximum peak SPL of around 110 dB which in a smallish room that booms should be loud enough. In a medium sized room that doesn't boom due to effective control of the room modes this wouldn't be quite loud enough for clean standard listening levels.
Small ribbons need to be crossed at 4-6 kHz in order to keep distortion low at standard listening levels. There isn't much energy in music at these frequencies so the low power handling tends not to be an issue. So long as you avoid things like clipping amplifiers and loud white noise you should be fine.
Do you know if you like/prefer the characteristic sound of ribbons to dome tweeters? If not it may be wiser to start with a good dome rather than a cheap ribbon. Here is a bit of discussion with supporting measurements.
400 Hz crossover frequency is too low for a 2" driver. 600-800 Hz is a more a realistic value if you are to avoid distortion at standard listening levels. If you want to crossover at this sort of frequency opt for a 4" midrange.
4000 Hz crossover frequency is in the right ballpark for a ribbon or 3/4" dome but a 1" dome could be crossed lower. Would you rather listen to a small rigidly moving tweeter dome or a larger midrange cone/dome that is not moving rigidly?
Your use of active programmable crossovers will of course allow you to explore the audibility of this type of thing for yourself.
Your woofers and amp will give a maximum peak SPL of around 110 dB which in a smallish room that booms should be loud enough. In a medium sized room that doesn't boom due to effective control of the room modes this wouldn't be quite loud enough for clean standard listening levels.
Small ribbons need to be crossed at 4-6 kHz in order to keep distortion low at standard listening levels. There isn't much energy in music at these frequencies so the low power handling tends not to be an issue. So long as you avoid things like clipping amplifiers and loud white noise you should be fine.
Do you know if you like/prefer the characteristic sound of ribbons to dome tweeters? If not it may be wiser to start with a good dome rather than a cheap ribbon. Here is a bit of discussion with supporting measurements.
400 Hz crossover frequency is too low for a 2" driver. 600-800 Hz is a more a realistic value if you are to avoid distortion at standard listening levels. If you want to crossover at this sort of frequency opt for a 4" midrange.
4000 Hz crossover frequency is in the right ballpark for a ribbon or 3/4" dome but a 1" dome could be crossed lower. Would you rather listen to a small rigidly moving tweeter dome or a larger midrange cone/dome that is not moving rigidly?
Your use of active programmable crossovers will of course allow you to explore the audibility of this type of thing for yourself.
FA123 seems okay. id take the extra money saved and get twin 8 inch woofers
I agree with andy, get a 4 inch mid rather then a 2 inch dome. will sound more natural, allow a lower xo point which will increase the chance of a "transparent" xo.
Id even opt for a 5 inch mid myself and try to xo at 250hz.
I agree with andy, get a 4 inch mid rather then a 2 inch dome. will sound more natural, allow a lower xo point which will increase the chance of a "transparent" xo.
Id even opt for a 5 inch mid myself and try to xo at 250hz.
If you are using a 4" mid and 8-10" woofers, the xover will likely be better and fall into place easier around 400-500Hz.
2" dome and the right 8" woofer with xover at 850Hz has been very transparent and my reference for about 8 years now.
As to the "ribbons are terrible" logic, I used the Airborne RT5002 AMT in a build, and it's HD in totality (and 2nd harmonic and up) is measured as below 0.5% from 1k+ with 105dB output. This turns that argument on its ear.
Later,
Wolf
2" dome and the right 8" woofer with xover at 850Hz has been very transparent and my reference for about 8 years now.
As to the "ribbons are terrible" logic, I used the Airborne RT5002 AMT in a build, and it's HD in totality (and 2nd harmonic and up) is measured as below 0.5% from 1k+ with 105dB output. This turns that argument on its ear.
Later,
Wolf
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