Well, since he didn't build them and he wasn't answering your question, merely stating that he liked somebody else's build (which he is entitled to do), probably not.
FWIW, I suspect the phase plugs were from Dave Dlugos (Planet10): planet_10 hifi -they look like his anyway.
FWIW, I suspect the phase plugs were from Dave Dlugos (Planet10): planet_10 hifi -they look like his anyway.
Sorry, this thread is old and lost track, I believe the plugs are from planet 10. They were in them when I bought them. Thanks
Hello from 2019! hehehehe
Sir, I'm planning to built this exactly same enclosure, and use the Fostex FE208EZ + T900A super horn tweeter.
I'm trying to talk with people that in fact builded this loudspeaker and listened to they on a daily basis, it's having been difficult to find I must say..
Please let me ask you, do you still have this loudspeakers?
What your thoughts about the bass performance?
Do you know how low they go on low frequencies?
My main concern is if with this design a subwoofer is vital?
Appreciate very much your thoughts about your experience with this loudspeakers..
Many thanks! Best Regards!
Requirement for sub(s) would be very much dependent on room size/speaker location and program material. Vital? - maybe not, but I've yet to heard a single driver/FR system that didn't benefit from highpass filtering - whether passive line level or "active" - and separately powered bass support.
Hello sir, thanks for your info.
Can you please elaborate this again?
I'm not too versed on some technical aspects, what is a high pass filter? is related to the crossover I presume?
instead of use the "one capacitor" design, that is explained on the Fostex enclosure plan, in order to crossover the full range and super horn tweeter, high pass filter is some kind of a more elaborated crossover?
Or I understood this wrong?
Appreciate very much your help to make me understand...
Best regards!
Can you please elaborate this again?
I'm not too versed on some technical aspects, what is a high pass filter? is related to the crossover I presume?
instead of use the "one capacitor" design, that is explained on the Fostex enclosure plan, in order to crossover the full range and super horn tweeter, high pass filter is some kind of a more elaborated crossover?
Or I understood this wrong?
Appreciate very much your help to make me understand...
Best regards!
There are lots of far more eloquent and technically proficient explanations available on the 'net than I can attempt, but to grossly over simplify things, a crossover - or more accurately "frequency dividing" filter network filter can be set at any point you want.
There are many ways to skin this cat, but for now let's assume you're talking about simple passive filter networks operating at low impedance/speaker level, and using a single amplifier channel per speaker.
To prevent excessive overlap of output from the drivers involved and to avoid distortion products from drivers operating beyond their respective optimal ranges, there are usually complementary low and high pass filters for each, which are usually, but not always hinged at the same frequency. In the case of drivers designed for full range operation such as the Fostex cited, most have benign enough behavior at the top end of their bandwidth that low pass filters are not necessarily mandatory - but with tweeters / super tweeters, high pass filters most certainly are. Many of us full range aficionados prefer simple first order function for such high pass filters, which can be achieved with a single capacitor the value of which can be easily determined by on line calculators, and in the case of Fostex's recommendations, the suggested values are probably a safe bet.
While the math for first order filter functions remains the same regardless of frequency, the resulting values calculated for high passing for addition of subs to something like the FE206 or 208 at a frequency of, let's say 80 Hz, and with woofers of 8ohms, the capacitor value would be approx 200mF, and inductor of approx 12mH for the woofer. As many of us would highly recommend film types over electrolytics and air core coils, the cost can escalate pretty quickly.
Of course the alternative is to go active - i.e. an independent amplifier channel per driver, with the filter function ahead of the amp. Again, at the risk of oversimplifying things, the math used to calculate C and L for any crossover frequency includes value for the impedance into which the filter will be operating, and the formula is the same whether that load is a speaker voice coil, or amplifier input state. Amplifiers will have an input impedance thousands of times higher than the DC resistance of almost any loudspeaker's voice coil, resulting in much lower and affordable values calculated for C. As most of us avid DIY speaker builders will likely have more than a couple of extra amps kicking around, this means only a few dollars for the passive components required. I'd refer you to TLS.org | Passive Line-Level Crossover for a brief explanation and link to calculator. While it's nowhere near as flexible as a fully active electronic crossover, I've personally used this approach more than a few times with great success.
There are many ways to skin this cat, but for now let's assume you're talking about simple passive filter networks operating at low impedance/speaker level, and using a single amplifier channel per speaker.
To prevent excessive overlap of output from the drivers involved and to avoid distortion products from drivers operating beyond their respective optimal ranges, there are usually complementary low and high pass filters for each, which are usually, but not always hinged at the same frequency. In the case of drivers designed for full range operation such as the Fostex cited, most have benign enough behavior at the top end of their bandwidth that low pass filters are not necessarily mandatory - but with tweeters / super tweeters, high pass filters most certainly are. Many of us full range aficionados prefer simple first order function for such high pass filters, which can be achieved with a single capacitor the value of which can be easily determined by on line calculators, and in the case of Fostex's recommendations, the suggested values are probably a safe bet.
While the math for first order filter functions remains the same regardless of frequency, the resulting values calculated for high passing for addition of subs to something like the FE206 or 208 at a frequency of, let's say 80 Hz, and with woofers of 8ohms, the capacitor value would be approx 200mF, and inductor of approx 12mH for the woofer. As many of us would highly recommend film types over electrolytics and air core coils, the cost can escalate pretty quickly.
Of course the alternative is to go active - i.e. an independent amplifier channel per driver, with the filter function ahead of the amp. Again, at the risk of oversimplifying things, the math used to calculate C and L for any crossover frequency includes value for the impedance into which the filter will be operating, and the formula is the same whether that load is a speaker voice coil, or amplifier input state. Amplifiers will have an input impedance thousands of times higher than the DC resistance of almost any loudspeaker's voice coil, resulting in much lower and affordable values calculated for C. As most of us avid DIY speaker builders will likely have more than a couple of extra amps kicking around, this means only a few dollars for the passive components required. I'd refer you to TLS.org | Passive Line-Level Crossover for a brief explanation and link to calculator. While it's nowhere near as flexible as a fully active electronic crossover, I've personally used this approach more than a few times with great success.
Chrisb, thank you very much for your detailed explanation, I must say that I do not understood fully, because I'm not versed very well in some technical aspects (still working on this 🙂
Please, let me ask you, I saw a device this days, that some people uses to cross the full range and super tweeter, called Lpad, for what I understood it's a single capacitor, attached to an attenuator i think...
What is the point of about this choice for the crossover? instead of to use just one capacitor?
Many thanks sir.
Please, let me ask you, I saw a device this days, that some people uses to cross the full range and super tweeter, called Lpad, for what I understood it's a single capacitor, attached to an attenuator i think...
What is the point of about this choice for the crossover? instead of to use just one capacitor?
Many thanks sir.
Because many of the horn type super tweeters in Fostex line have substantially higher sensitivity than the main / FR drivers with which they're typically used, the L-pad is essentially like a volume control - a continuously variable version of two resistors required to provide the necessary attenuation. They are used in addition to the filter capacitor, without which -unlike the FR driver - the tweeter could be expected to have a very short lifespan. Here's a extract from Fostex spec sheet for T90A on how those would be connected - ignore the dual FE208s.
An externally hosted image should be here but it was not working when we last tested it.
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Do you think that at first, is better crossover without the Lpad solution? and just try the Lpad if not satisfied with the previous solution? (one capacitor wiithout Lpad)?
Thanks.
Thanks.
OK, this is starting to get silly.
-Do you know what an Lpad is? It is used to attenuate the output of a drive unit.
-Have you looked at any of the driver data? Look at the frequency response plots. You see that tweeter? You see it has about 6dB greater sensitivity than the FE208ESigma? You think you might want to reduce that, or would you prefer it to be about 6dB louder than the main driver?
-If you don't want the tweeter to be about 6dB louder than the main driver, then you need to attenuate it with either the Lpad mentioned, or fixed resistors. The Lpad, being adjustable, gives you more room to experiment with level.
Now: what conclusion are you going to draw?
-Do you know what an Lpad is? It is used to attenuate the output of a drive unit.
-Have you looked at any of the driver data? Look at the frequency response plots. You see that tweeter? You see it has about 6dB greater sensitivity than the FE208ESigma? You think you might want to reduce that, or would you prefer it to be about 6dB louder than the main driver?
-If you don't want the tweeter to be about 6dB louder than the main driver, then you need to attenuate it with either the Lpad mentioned, or fixed resistors. The Lpad, being adjustable, gives you more room to experiment with level.
Now: what conclusion are you going to draw?
Loudness level gain volume perception dB factor volume conversion ratio gain level in decibels formula dB field quantity energy size power voltage damping convert to factor attenuation amplification acoustic intensity cause sound pressure effect volu
This may clear things up or may confuse you even more. According to the table you will perceive the tweeter to be 1.516 times louder than the FE208e without the l-pad.
This may clear things up or may confuse you even more. According to the table you will perceive the tweeter to be 1.516 times louder than the FE208e without the l-pad.
By the way, appreciate if you can clarify the differences between this 3 types of attenuators from Fostex:
https://www.fostexinternational.com/docs/speaker_components/pdf/att.pdf
For what I understood, R80B and R82B are the same, the difference is that R80B can handle more power.
What about the R100T?
It can attenuate less dBs, but more precisely? and have a transformer inside will provide a better sound quality?
Thanks!
https://www.fostexinternational.com/docs/speaker_components/pdf/att.pdf
For what I understood, R80B and R82B are the same, the difference is that R80B can handle more power.
What about the R100T?
It can attenuate less dBs, but more precisely? and have a transformer inside will provide a better sound quality?
Thanks!
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