As LS3/5A's drivers are out of production long ago, I started searching for modern drivers to make something like a clone of LS3/5A. Here, SEAS drivers are used, in this case 27TDF (H1211) cloth tweeters, CA15RLY(H1216) paper woofer. Can anyone check the crossover to see if it is correct? BTW I used a LR2 @3kHz only to keep the crossover simple and I guess these drivers are up to the task. The cab will be exactly the LS3/5A cab.
A million thanks.
A million thanks.
Attachments
Your Fs is a little more at 44 Hz.
Why do you have "copyed" the xover. The "15Ohm" BBC LS3/5A. Is it the starting point, for you? Objective?
Some use Aurum Cantus AC-130F1 with Fs=35Hz. But Zaph shows test with Fs=50Hz, maybe in a box, investigate his tests/conditions. I didn't check anything else until having more details.
Aurum cantus
Zaph|Audio
https://www.madisound.com/store/product_info.php?cPath=45_228_254&products_id=8301
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First, this crossover is a simple second order passive design suggested by the calculations of WinISD so it is not related to the original BBC LS3/5A.
I wanted to make a compact speaker and the LS3/5A looks like a good one but the sensitivity is too low for my taste so I have give up the original BBC crossover design and of course I may make an external passive bass boost too so that I can use it when I am using more powerful amp and leave it when I'm using T-amp or valve amp.
SEAS drivers are used as they are widely available and are carried by Madisound so it's more convenient for me to buy.
At last, thanks for your advice, I may wanna try the Aurum Cantus next time.
I wanted to make a compact speaker and the LS3/5A looks like a good one but the sensitivity is too low for my taste so I have give up the original BBC crossover design and of course I may make an external passive bass boost too so that I can use it when I am using more powerful amp and leave it when I'm using T-amp or valve amp.
SEAS drivers are used as they are widely available and are carried by Madisound so it's more convenient for me to buy.
At last, thanks for your advice, I may wanna try the Aurum Cantus next time.
Good.
SB Acoustics SB15NRXC30-8 5" Woofer (previous post)
This also looks like a good candidate (for the price asked).
Silver Flute W14RC25-08 ohm 5-1/2" Wool Cone
Scan-Speak 15W/8434G00 Discovery, 5.25" Midwoofer
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I may need a higher order crossover, hence a more complicated crossover for the Silver Flute to avoid that peak at 8kHz. The SEAS is smooth up to 10kHz so I feel more comfortable to cross it at 3kHz via LR2 but the Silver Flute seems like asking for at least a LR3 or even LR4. The Silver Flute maybe a decent candidate, but I think the 2nd order crossover I designed is complicated for a newbie like me already.
I'm thinking of dropping the Zobel network to save two components for the external bass boost now.
Thanks for your advice again.
I'm thinking of dropping the Zobel network to save two components for the external bass boost now.
Thanks for your advice again.
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Others deserving attention for some simulations are the expensive serious drivers from AudioTechnology - C-Quenze & Flexunits 4 inches types, Sd: 96 cm2, the first one looking better from the point of view of Fs.
Flexunits 4 H 52 06 13
C-Quenze 15 H 52 06 13 SD
Flexunits 4 H 52 06 13
C-Quenze 15 H 52 06 13 SD
If you want a 1st class LS3/5A-size speaker, and keep the XO simple, the Mark Audio Alpair7 fits nicely into a sealed box of that size.
Due to Hoffman's Iron law, a box this size will never be overly efficient (a trade-off between efficiency & bass extension), but with the simple XO (ie none) A7 is more efficient than a real LS3/5A.
A7 is also available in Honk Kong -- if you can, arrange with Mark to pick-up and listen to some of the stuff in his studio.
dave
Due to Hoffman's Iron law, a box this size will never be overly efficient (a trade-off between efficiency & bass extension), but with the simple XO (ie none) A7 is more efficient than a real LS3/5A.
A7 is also available in Honk Kong -- if you can, arrange with Mark to pick-up and listen to some of the stuff in his studio.
dave
I'm not expecting anything terribly efficient at all and I have no plans to build a true LS3/5A. Mark's Alpair 7 must be great, but I'm trying to experiment with a two way design and be as close to the original BBC design as possible without messing up with a complicated crossover. So, with a more capable tweeter, I cross it with 2nd order instead of 3rd order, the crossover frequency is still 3kHz, and I may add an external 2 components bass boost at around 120Hz to bring the BBC midbass hump.
BTW, I may find Mark for the CHR70 for my desktop setup later as well.
BTW, I may find Mark for the CHR70 for my desktop setup later as well.
Calypso
Hi,
The above is a good way of using those original drivers.
But its nothing like an LS3/5a because there is no reason it
should be, they are completely different drivers. The box
volume could be reduced for sealed but thats about it.
This would work sealed in L33/5a cabinets :
Zaph|Audio - 4" Bargain Mini
Lots of features are similar to the LS3/5a including driver sizes, low
efficiency, low power handling and if built sealed no real low bass.
Still it would sound surprisingly not far off LS3/5a's, but different.
But for more efficiency and power handling consider the 7L sealed or 10L vented :
https://www.madisound.com/store/product_info.php?products_id=8643
Zaph|Audio - ZA14W08 Woofer
https://www.madisound.com/store/product_info.php?products_id=8664
And take advantage of these guys hard work :
Zaph|Audio - Design Contest Results
Or go with the higher value (budget high value tweeter) ZA5 :
Zaph|Audio - ZA5 Speaker Designs with ZA14W08 woofer and Vifa DQ25SC16-04 tweeter
You'd be hard pushed to do better.
/Sreten.
Hi,
The above is a good way of using those original drivers.
But its nothing like an LS3/5a because there is no reason it
should be, they are completely different drivers. The box
volume could be reduced for sealed but thats about it.
This would work sealed in L33/5a cabinets :
Zaph|Audio - 4" Bargain Mini
Lots of features are similar to the LS3/5a including driver sizes, low
efficiency, low power handling and if built sealed no real low bass.
Still it would sound surprisingly not far off LS3/5a's, but different.
But for more efficiency and power handling consider the 7L sealed or 10L vented :
https://www.madisound.com/store/product_info.php?products_id=8643
Zaph|Audio - ZA14W08 Woofer
https://www.madisound.com/store/product_info.php?products_id=8664
And take advantage of these guys hard work :
Zaph|Audio - Design Contest Results
Or go with the higher value (budget high value tweeter) ZA5 :
Zaph|Audio - ZA5 Speaker Designs with ZA14W08 woofer and Vifa DQ25SC16-04 tweeter
You'd be hard pushed to do better.
/Sreten.
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From WinISD, I got f3=90Hz with the SEAS in 5L sealed, which is similar to that of KEF B110 in 5L sealed, so I thought they might be almost compatible despite the fact that their Thiel Small Parameters are so different(Qts is almost identical, though). The size is almost the same as well, SEAS has a diameter of 112mm while B110 is 113mm. B110 is not super inefficient itself, but with the equalization in LS3/5A it is, and with a passive bass boost, I get 3dB less efficient resulting in about 83dB/m per pair.
Thanks for your advice very much, but I'm now more worried about my crossover scheme. BTW, the unit of a capacity is wrong, it should be 9.38uF instead of mH.
Thanks for your advice very much, but I'm now more worried about my crossover scheme. BTW, the unit of a capacity is wrong, it should be 9.38uF instead of mH.
Hi,
You should be. I haven't looked at in any detail because I can trust the
Calypso c/o as all design details are given, whilst for yours you state its
LR2@3KHz with no further detail, and TBH it does not look like at first
inspection a LR2 acoustic crossover to me, and this is what the Calypso
crossover is designed to do, so I would go with its details.
But personally I'd also go with a Zaph 7L sealed.
/Sreten.
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I will go to the electronics store to see which kind of inductors or capacitors I will need, and I actually prefer air core inductors and polypropene caps. It's a symmetrical LR2 design and with the wide bandwidth of both drivers within their comfortable frequencies, it should be acoustically 2nd order as well. Calypso did not say much about the zobel network inside his design so that's why they do not look alike. The LR2 is actually made up of only 2 caps and 2 inductors, a cap in series with the tweeter with an inductor in parallel and an inductor in series with the woofer with a cap in parallel. That's it.
Sreten, I checked my values with WinISD calculator and the crossover bit seems to be fine. The L-pad is identical to the Calypso and the BSC is calculated from the excel spreadsheet and it seems to be fine too. If I am right, the Calypso design is an inch wider and that may account for different values in the BSC. I didn't add any zobel network to the tweeter and that may be the difference.
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