Finished mine after about 40 hours.
Just wanna thank the guys here for the ideas. They sound great, perhaps a little weakish on the bass, but make up for it in clarity.
An externally hosted image should be here but it was not working when we last tested it.
An externally hosted image should be here but it was not working when we last tested it.
Just wanna thank the guys here for the ideas. They sound great, perhaps a little weakish on the bass, but make up for it in clarity.
FR125S + Peerless 830875
Not quite a fullrange.... more fullrange with help..... but a use for some FR125S drivers I had and partnered with some Peerless 830875 Nomex woofers. Been a fun project and ended up a smooth laid back speaker.
http://www.rzaudio.com/rz52/mongrel.htm
Not quite a fullrange.... more fullrange with help..... but a use for some FR125S drivers I had and partnered with some Peerless 830875 Nomex woofers. Been a fun project and ended up a smooth laid back speaker.
http://www.rzaudio.com/rz52/mongrel.htm
Attachments
Hey guys,
Wow, long thread! - After learning about and deciding to buy myself a T-amp to play with and mod (I'm a little late to the party - this is all new to me), I wanted to build myself a decent pair of simple, full range speakers to be able to enjoy music with.
After deciding to use either a Fostex FE207 or FE127, I stumbled across this thread....
Well, 69 pages later - I have ordered a pair of 127's, my T-amp, and some assorted caps - and I am juiced to get started building a pair of the folded monopole design!
Thanks to you guys for starting the thread and developing the designs - I likely wouldn't even be giving this a try if it wasn't for all of your work!
Now I just want the stuff to get here, so I can get started!!
Wow, long thread! - After learning about and deciding to buy myself a T-amp to play with and mod (I'm a little late to the party - this is all new to me), I wanted to build myself a decent pair of simple, full range speakers to be able to enjoy music with.
After deciding to use either a Fostex FE207 or FE127, I stumbled across this thread....
Well, 69 pages later - I have ordered a pair of 127's, my T-amp, and some assorted caps - and I am juiced to get started building a pair of the folded monopole design!
Thanks to you guys for starting the thread and developing the designs - I likely wouldn't even be giving this a try if it wasn't for all of your work!
Now I just want the stuff to get here, so I can get started!!
I have been lurking this thread and finally I finished reading it.
I have two Sonic Impact t-amp modified with new caps, etc. and I got a tube preamp for this.
I will be building Gio's FE127E sealed bipoles, to be used with my t-amps. As Gio explained, he is using a subwoofer. I will be using a 10" subwoofer set at around 80 to 100Hz.
Hope this will work.
I have two Sonic Impact t-amp modified with new caps, etc. and I got a tube preamp for this.
I will be building Gio's FE127E sealed bipoles, to be used with my t-amps. As Gio explained, he is using a subwoofer. I will be using a 10" subwoofer set at around 80 to 100Hz.
Hope this will work.
I'll have you know that if there's any lurking to be done, I'm the only one who'll be doing it... 
Sounds a plan. My only slight concern is that with the sub crossever over that high, you could well end up hearing the LF from one location and everything else from another. Sound localisation only really drops off below ~75Hz.
Sounds a plan. My only slight concern is that with the sub crossever over that high, you could well end up hearing the LF from one location and everything else from another. Sound localisation only really drops off below ~75Hz.
alexg said:
Depends a lot on the crossover in the sub and if it's 2nd order like most sub amps there's still quite a bit of information that sneaks through but less of a problem with 4th order crossovers on subs.
Try the sub with stereo music (not HT LFE channel) and listen if voices come through. You'll usually get a bit but if it's too noticable, then drop the sub crossover point.
Hi alexq,
Be sure to keep us posted on your progress!
A sealed enclosure rolls off naturally at 12 dB/octave (2nd order).
With WinISD, a second order sub @ 85Hz should be optimal and is a good place to start. The Martin King models say 75Hz. Of course at these low frequencies it will be room dependant so you will have to experiment with the cross over point.
For me, 80Hz 2nd order has been working very well. Very rarely do I notice localization.
Now that you guys mention localization, you have got me thinking.
If you run the speakers in parallel for a 4 ohm load and then add a 4 ohm resistor in series for an 8ohm load, this should bump up the Q of the drivers and get you more bass at the cost of some efficiency. Then you should be able to drop the crossover point a little more. I will have to try this out.
Be sure to keep us posted on your progress!
A sealed enclosure rolls off naturally at 12 dB/octave (2nd order).
With WinISD, a second order sub @ 85Hz should be optimal and is a good place to start. The Martin King models say 75Hz. Of course at these low frequencies it will be room dependant so you will have to experiment with the cross over point.
For me, 80Hz 2nd order has been working very well. Very rarely do I notice localization.
Now that you guys mention localization, you have got me thinking.
If you run the speakers in parallel for a 4 ohm load and then add a 4 ohm resistor in series for an 8ohm load, this should bump up the Q of the drivers and get you more bass at the cost of some efficiency. Then you should be able to drop the crossover point a little more. I will have to try this out.
More lower mids
Im feeling like my folded monopoles arent really putting out as much in the lower midrange as I had hoped. It just seems that in comparison to many speakers near the same size they just arent filling the room nearly as well.
Granted they only have about 50 hours on them, and they already sound better than they did at first, but I am not optimistic that they will eventually fill the room a lot better.
One thing that was suprising to me was how much stuffing I was putting in. I put in the recommended 1/2 a pound for each cabinet, and it was packed in there pretty tight by the time I was done. Could it be that its so tight that it is muffling the lower mids?
Im being overly nitpicky here, I really do like the sound, and will eventually combine them with a sub, but I feel like the 200-600hz range is just a tad weak.
Thanks,
George
Im feeling like my folded monopoles arent really putting out as much in the lower midrange as I had hoped. It just seems that in comparison to many speakers near the same size they just arent filling the room nearly as well.
Granted they only have about 50 hours on them, and they already sound better than they did at first, but I am not optimistic that they will eventually fill the room a lot better.
One thing that was suprising to me was how much stuffing I was putting in. I put in the recommended 1/2 a pound for each cabinet, and it was packed in there pretty tight by the time I was done. Could it be that its so tight that it is muffling the lower mids?
Im being overly nitpicky here, I really do like the sound, and will eventually combine them with a sub, but I feel like the 200-600hz range is just a tad weak.
Thanks,
George
A few ideas:
If you're listening to them mounted on the floor as shown, try tilting them up between 5-8 degrees, or mounting on simple stand 12-14" off floor.
Hate to ask the obvious, but have you checked phasing on internal connections and speaker wiring? As recently as last weekend I made the same mistake when moving things from one end of a room to the other.
Assuming you can get at all the stuffing locations in the box, try pulling at least half out, and then play up & down from there.
I'm a firm believer that after all the math is said & done, it's still up to your ears to tell you what sounds right.
I'm familiar enough with the performance of this design to know that filling even a moderate sized open space room shouldn't be a problem, except for the bottom octave or so.
If you're listening to them mounted on the floor as shown, try tilting them up between 5-8 degrees, or mounting on simple stand 12-14" off floor.
Hate to ask the obvious, but have you checked phasing on internal connections and speaker wiring? As recently as last weekend I made the same mistake when moving things from one end of a room to the other.
Assuming you can get at all the stuffing locations in the box, try pulling at least half out, and then play up & down from there.
I'm a firm believer that after all the math is said & done, it's still up to your ears to tell you what sounds right.
I'm familiar enough with the performance of this design to know that filling even a moderate sized open space room shouldn't be a problem, except for the bottom octave or so.
Thanks chris
Heh Im pretty sure I got the phase right, but Ill just switch em to make sure.
I worry a little about unscrewing the driver again, as I have already unscrewed it and rescrewed it once, to put the grills on.
As for tilting them up, I now have them in a different setup in my bedroom on a desk, about 8 inches from the wall.and its not that they dont fill the room, its just they fill it with their beautiful mids and highs and not so much else.
Thanks chris, youve been a huge help,
George
Heh Im pretty sure I got the phase right, but Ill just switch em to make sure.
I worry a little about unscrewing the driver again, as I have already unscrewed it and rescrewed it once, to put the grills on.
As for tilting them up, I now have them in a different setup in my bedroom on a desk, about 8 inches from the wall.and its not that they dont fill the room, its just they fill it with their beautiful mids and highs and not so much else.
Thanks chris, youve been a huge help,
George
I think i mentioned it before, but it is worth rpeating. A significant improvement in the FE127 (&126) can be had by modifying them (if i do say so myself).
It is quite hard to get a good pic...
These mods are a direct result of comments Mark MacKenzie made earlier on in this thread crossed with my 30 years of experience modding drivers. More info on my planet10-hifi site (including a link to the FR Forum where i posted early results). I will be getting up a more detailed how-to on my website, but that is just one of many tasks in my queue.
dave
It is quite hard to get a good pic...
These mods are a direct result of comments Mark MacKenzie made earlier on in this thread crossed with my 30 years of experience modding drivers. More info on my planet10-hifi site (including a link to the FR Forum where i posted early results). I will be getting up a more detailed how-to on my website, but that is just one of many tasks in my queue.
dave