I have build some stereo speakers based on the Fostex FE 103 Sol.
My intention is to build an now an single/mono full range speaker for using with a low power tube amp and/or radio.
For a shorter listenig distance of 3-4 meters and low volume for listening at late evening.
What do you think about an Fostex 168 or 208 EZ Sigma as driver?
How they behave on low listening volumes?
My intention is to build an now an single/mono full range speaker for using with a low power tube amp and/or radio.
For a shorter listenig distance of 3-4 meters and low volume for listening at late evening.
What do you think about an Fostex 168 or 208 EZ Sigma as driver?
How they behave on low listening volumes?
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Those drivers need a back loaded horn to get any bass out of them. A BIB might be a good choice to bring some bass gain at low volume. I run a FF105WK in a TL and that produces nice deep 60Hz bass at low volumes.
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Based on your need, I don't think you should bother with the complexity and size of a BLH for this project. I would suggest a Mark Audio Pencil enclosure with one of the MA drivers.
Hmm, based on a system I did for an apartment dwelling buddy long ago, a stereo pair of ~50 Hz, high Qt, ~90 dB eff., 5.25" car audio drivers in ~48" high MLTLs with a low distortion 4 W available is just right for your distance, SPL requirements; so for mono, then either >93 dB eff. or at least ~8 W + possibly more Xmax @ 90 dB eff. and/or changing driver size to get it, doubling or halving power [electrical and/or acoustical] for every 3 dB below/above.
As you can see, there's no simple answer without knowing the amp specs, room acoustics, frequency response ranges of the program material and what you mean by 'low volume' [average/peak SPL], i.e. the above is based on a ~75 dB average @ the listening position [LP] that I measured in his room, but it's a decades old apt. building with construction that may damp sound better than newer construction, at least in my locale judging by their near 'lean-to' construction, so figure his is more on a par with middle American construction that has colder weather over a longer period.
WRT how well a driver maintains its performance characteristics [accurately tracks the transients] at various power levels, it too depends a lot on cab loading, room acoustics, the system output impedance, though as a general rule one wants the highest Vas, lowest Qes specs to offset a SET's high output impedance and often weak power supply and with a Fs that's slightly below the lo west note it needs to reproduce since tuning to Fs is required to get best overall bass performance; or if PP, then a medium Qes in the ~.31-4 range and if it's output impedance falls below ~0.5 ohms, then up to a 0.7 Qes is fine for a tower reflex [MLTL] or even a BL or pipe horn if size isn't a major issue, though corner loading is preferred.
Anyway, once all these variables are known, the folks here that keep up with these types of drivers [not me anymore] should be able to provide some good choices, though based on what use to be the way to go with tubes would be either a Lowther, Audio Nirvana or similar in a BLH or a 10" audio Nivana [and preferably larger] 'FR' driver in a large sealed or [ML]TL depending on the system impedance, driver specs required.
GM
As you can see, there's no simple answer without knowing the amp specs, room acoustics, frequency response ranges of the program material and what you mean by 'low volume' [average/peak SPL], i.e. the above is based on a ~75 dB average @ the listening position [LP] that I measured in his room, but it's a decades old apt. building with construction that may damp sound better than newer construction, at least in my locale judging by their near 'lean-to' construction, so figure his is more on a par with middle American construction that has colder weather over a longer period.
WRT how well a driver maintains its performance characteristics [accurately tracks the transients] at various power levels, it too depends a lot on cab loading, room acoustics, the system output impedance, though as a general rule one wants the highest Vas, lowest Qes specs to offset a SET's high output impedance and often weak power supply and with a Fs that's slightly below the lo west note
Anyway, once all these variables are known, the folks here that keep up with these types of drivers [not me anymore] should be able to provide some good choices, though based on what use to be the way to go with tubes would be either a Lowther, Audio Nirvana or similar in a BLH or a 10" audio Nivana [and preferably larger] 'FR' driver in a large sealed or [ML]TL depending on the system impedance, driver specs required.
GM
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Thanks for the detailed technical explanations. It's a complex issue and need much knowledge.
Here in europe its difficult to get the Markaudio Alpair drivers, at least for an good price. So I'm limited to Fostex drivers.
The two 168 or 208 EZ Sigma's will need the addition of super tweeters, FE166En and FE208En too.
The FE103-Sol are that I have are very good but limited at low frequencies. Would there be any benefit of using the 16Ohm variants?
Then there is an FX120....?
What kind of music for this mono speaker project? (I will buy a suitable mono tube amp for the speaker) female jazz voices, acoustic guitar and bass mainly. So the driver should respond fast, crisp and punchy. Faster and crispier than my FE103SOL.
Here in europe its difficult to get the Markaudio Alpair drivers, at least for an good price. So I'm limited to Fostex drivers.
The two 168 or 208 EZ Sigma's will need the addition of super tweeters, FE166En and FE208En too.
The FE103-Sol are that I have are very good but limited at low frequencies. Would there be any benefit of using the 16Ohm variants?
Then there is an FX120....?
What kind of music for this mono speaker project? (I will buy a suitable mono tube amp for the speaker) female jazz voices, acoustic guitar and bass mainly. So the driver should respond fast, crisp and punchy. Faster and crispier than my FE103SOL.
Has anybody compared the recent FE206 and FE208EZ Sigma?
Many seem to prefer the FE206 for its upper frequencies, but is something "better" on the FE208EZ Sigma? The older 208 wasn't any special as many say.
Many seem to prefer the FE206 for its upper frequencies, but is something "better" on the FE208EZ Sigma? The older 208 wasn't any special as many say.
Not sure the project linked below is helpful except to say I have been listening in mono for just over a year since moving into my small apartment. I use the Fostex 168z (old style with whizzer) in a large ported box. The specs for this driver allow it to be used this way with good results. The drivers you are looking into work best in back loaded horns due to their low Qts and rising response.
I enjoy listening in mono. You still must find your sweet spot for best sound but overall you can move about your space and enjoy music without missing what's happening on the left or right channel. You can choose to listen critically but I find with mono I listen more causually.
If you have a corner I'd recommend BIBs. If not, I'd recommend another type of back horn for the 206 / 208... whichever version you choose.
I've never heard any of the 8" Fostex but if they are like the 168z that I have been enjoying for many years they are directional and will require some experimentation with placement to sound best. You may end up angling them (to avoid that 'in your face' sound) and adding a super tweeter to fill in the high frequencies.
https://speakerprojects.wordpress.com/2015/04/27/fostex-168z-projects/
I enjoy listening in mono. You still must find your sweet spot for best sound but overall you can move about your space and enjoy music without missing what's happening on the left or right channel. You can choose to listen critically but I find with mono I listen more causually.
If you have a corner I'd recommend BIBs. If not, I'd recommend another type of back horn for the 206 / 208... whichever version you choose.
I've never heard any of the 8" Fostex but if they are like the 168z that I have been enjoying for many years they are directional and will require some experimentation with placement to sound best. You may end up angling them (to avoid that 'in your face' sound) and adding a super tweeter to fill in the high frequencies.
https://speakerprojects.wordpress.com/2015/04/27/fostex-168z-projects/
How big a box can you live with?
As Jeff says many of the Fostex (all you have mentioned except for the SOL (althou we have only tried theSOL in FH3 so far)) really prefer to be in a horn, none of which are small and the best of are quite large.
My favorite Fostex are the FF85wk, FF105wk, FE103 SOL (none of which has much bass capability), and the FF165wk. I do modify the drivers i use which makes them better, and in some cases i minimize their problem areas. I tend to prefer the smaller drivers to the larger ones.
dave
As Jeff says many of the Fostex (all you have mentioned except for the SOL (althou we have only tried theSOL in FH3 so far)) really prefer to be in a horn, none of which are small and the best of are quite large.
My favorite Fostex are the FF85wk, FF105wk, FE103 SOL (none of which has much bass capability), and the FF165wk. I do modify the drivers i use which makes them better, and in some cases i minimize their problem areas. I tend to prefer the smaller drivers to the larger ones.
dave
>>> How did you do the stereo to mono conversion?
I set my iPad to mono. Settings>Accessibility>Mono.
I set my iPad to mono. Settings>Accessibility>Mono.
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Me too, I 'converted' to mono several years ago and haven't looked back. I have a large space and open concept house where a mono speaker provides sound all over. I use an open backed box - I find this provides more ambience.
>>> Me too, I 'converted' to mono several years ago and haven't looked back. I have a large space and open concept house where a mono speaker provides sound all over. I use an open backed box - I find this provides more ambience.
I know what you have Bigun and think it's pretty darn cool. Because you DIY you get to listen to music the way you like. I like mono because it removes the variables of stereo. I also like having a single spot where the music emanates - think of it as the stage where the musicians are playing. The open back (I've got an open baffle) does spread the sound around the room differently than a typical box. With an open box/baffle the image is more 'in the air' than directed at the listener. Some call it diffuse. I think it's better.
But when I do get to hear stereo it sounds really good too.
I know what you have Bigun and think it's pretty darn cool. Because you DIY you get to listen to music the way you like. I like mono because it removes the variables of stereo. I also like having a single spot where the music emanates - think of it as the stage where the musicians are playing. The open back (I've got an open baffle) does spread the sound around the room differently than a typical box. With an open box/baffle the image is more 'in the air' than directed at the listener. Some call it diffuse. I think it's better.
But when I do get to hear stereo it sounds really good too.
A big corner loaded reflex box with a big FR or coax worked in the 50's for mono, and it still works today.
For a smaller FR, I think you'll be better served with a mid to high Q driver, but there's no simple answer. An FE208EZ in a corner loaded horn might be pretty special, with an upfiring supertweeter.
The only Fostex sigma I've used are the little FE108eZ. Those are very sweet and slightly vintage sounding: detailed but not sterile. I assume the larger ones have a similar character, but might actually make bass.
For a smaller FR, I think you'll be better served with a mid to high Q driver, but there's no simple answer. An FE208EZ in a corner loaded horn might be pretty special, with an upfiring supertweeter.
The only Fostex sigma I've used are the little FE108eZ. Those are very sweet and slightly vintage sounding: detailed but not sterile. I assume the larger ones have a similar character, but might actually make bass.
Found an interesting youtube diy speaker based on the FE208EZ Sigma
https://www.youtube.com/watch?v=1_2NKvVaN-Y
This seems to be a smaller speaker
https://www.youtube.com/watch?v=1_2NKvVaN-Y
This seems to be a smaller speaker
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😀 Sometimes the easiest solutions are difficult to found.
Because I like my Tivoli One Radio very much and Horns are very big, I had the idea of mono.
This would result in much cheaper and faster construction of only one enclosure. Change can easier be made. Also I can build single tube pre and amps.
Aso as mentioned its easier to turn the the mono speaker into different directions.
But because I'm using an stereo dac and amp I would have to found a stereo to mono conversion circuit.
I am about to try using a couple of 10k resistors (center tap is input to amp) as a cheap stereo to mono summing junction between the source and the amp at line level. I have heard that this can work as I often play from a CD player.
If the amp is stereo too, it may be better to do the summing between the amp and the mono speaker, after amplification.
If the amp is stereo, you could utilise the two mono channels separately if you mono the channels before the power amp. For instance you could have a full range but bass light speaker on one, and some form of bass enhancement on the other. It frees up the full range speaker possibilities.
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