TEXAS TOMM said:
i have been though most of the lowther range, I have some of organised the world designs and now the audio-talk forum meets in doncaster( we have another next month.. see the audio-talk forum) we usually have with a room full of fostex based speakers..
i built a pair of fidelio's about 10 years ago they had dx3 , they were good,
since then i built some much bigger 3.6m tratrix horns, much better sound..
but i spent years not hearing the colour from the horn.. but when i did.. it changed my view about horns( and boxes)
i now use ex4 in open baffle with a couple of 12" drivers per channel, doing bass duties..
2 watts is loud... very loud.. 4 watts is pub/disco levels
the quality of the amp can make so much difference too..
I am very happy with them...
Scott (scottmoose) paid them quite a compliment last week
he said they where as far removed from main stream hi fi as you could get
Some of the fostex drivers are quite good, but none seem as full range as my lowthers , and they also sound smoother and much more detailed than most of the fostex drivers i've heard.
lowthers may seem expensive..
i would not swap
the FE208E Sigma and tweeter is a good combination, nice smooth sound.. ,more bass than a single lowther, in the right cab
but .. there's an extra level of detail in my drivers
steve
Hi Steve,
On OB, did you try removing the EX driver rear cover plates with all of the circular holes. These must reflect rear radiation back through the cone?
Cheers ...... Graham.
On OB, did you try removing the EX driver rear cover plates with all of the circular holes. These must reflect rear radiation back through the cone?
Cheers ...... Graham.
As a newcomer to speaker building, I am grateful for all this information, but I must say that the more I learn, the more confused I become! I am now intrigued with the possibilities of OB design. Given that I expected to utilise a subwoofer anyway. What is the highest frequency that I could crossover at without losing integration of the overall sound? My reading suggests around 130Hz - could it be higher if I use 2 subwoofers. I would wish to use an active crossover, so my 2a3 amp would supply the main component of the music, and I would use a high power transistor / chip based amp (ie. a chip based pcb kit - Maplin or similar) for the subwoofers. Can anyone point me to a very good crossover? --- The valve amp has 2 or 3 inductors -- o/p, interstage, and optional switched transformer attenuators on the input. How would the phase -shift difference between the amplifiers affect the integration? Is there maybe a complete subwoofer amp that contains crossover, amp, and phase-shift ajustment?
Graham,
Different application, but.....
I put a pair of EX2's in MLTL's. Never worked right. The drivers wouldn't load the cabinets properly. I removed the rear baskets and the drivers loaded up as predicted. For the extra price of EXx drivers, you also get the lemon squeezer phase plug. I replaced these with the bullet phase plugs -- better dispersion. So, I now have DX2's in all features except the die cast magnet covers.
The EXx is advertised as controlling the back wave. This may be fine in a tight compression chamber, but for resonant cabinets, and I presume OB, where the back wave is important, the DXx is the way to go.
Bob
Different application, but.....
I put a pair of EX2's in MLTL's. Never worked right. The drivers wouldn't load the cabinets properly. I removed the rear baskets and the drivers loaded up as predicted. For the extra price of EXx drivers, you also get the lemon squeezer phase plug. I replaced these with the bullet phase plugs -- better dispersion. So, I now have DX2's in all features except the die cast magnet covers.
The EXx is advertised as controlling the back wave. This may be fine in a tight compression chamber, but for resonant cabinets, and I presume OB, where the back wave is important, the DXx is the way to go.
Bob
For higher overall SPL, there has been a lot of discussion lately about 2-way speakers that use the FR driver as a mid-tweet. I really believe that this is the right approach. Lowther drivers shine above 300Hz. Why try to use them at 30Hz where they suck? Now if I could only find the sub that fits my space.
I totally agree. But most true subs start rolling off early and will not make it to the mids.
If you look at the complexity thats necessary for something like the A166 then two drivers (W/WB) appears to be a simple solution. Go with a small OB or IB on the WB and be done with it.
ron
I totally agree. But most true subs start rolling off early and will not make it to the mids.
If you look at the complexity thats necessary for something like the A166 then two drivers (W/WB) appears to be a simple solution. Go with a small OB or IB on the WB and be done with it.
ron
Graham Maynard said:
they still have the backs on graham.. i may have to remove them to see if there's much of a difference, myself and scott thought they sounded very well as they are... so they have been left on
my own thoughts where, as they are sited quite close to the back wall, there was there was enough high mids from the front of the driver without adding the back wave.. i have tried my best not to put too much electrical eq in there and have spent alot of time on the baffle shape and angles, and then on the amps which can have a bigger impact on the sound, ie bass and treble extension..
I'm currently running globe px4 though tribute outputs in a simple 2 stage amp.
steve
cheers steve
>>> did you try removing the EX driver rear cover plates...
Sometimes i wonder about this hobby of ours. It can get expensive. Meanwhile, i am having fun EQing a cheap B20. I am not sold on using a fullrange driver in a sealed or OB plus a woofer yet because the fullness of the sound can get lost with these types of designs in my experience (not that everyone has the same experience). Using a fullrange driver down to 30hz (where they suck, as someone said earlier) works because a fullness of sound can be achieved (as well as speed, dynamics, efficiency). But this is at the expense of real bass. That's the compromise and some are willing to live with it. Maybe blending a fullrange driver that's simply screwed to an OB and blending an appropriate woofer is an excellent alternative but it will also have its compromises. I would imagine efficiency would be lower than a back horn for example.
Sometimes i wonder about this hobby of ours. It can get expensive. Meanwhile, i am having fun EQing a cheap B20. I am not sold on using a fullrange driver in a sealed or OB plus a woofer yet because the fullness of the sound can get lost with these types of designs in my experience (not that everyone has the same experience). Using a fullrange driver down to 30hz (where they suck, as someone said earlier) works because a fullness of sound can be achieved (as well as speed, dynamics, efficiency). But this is at the expense of real bass. That's the compromise and some are willing to live with it. Maybe blending a fullrange driver that's simply screwed to an OB and blending an appropriate woofer is an excellent alternative but it will also have its compromises. I would imagine efficiency would be lower than a back horn for example.
Godzilla said:
it is expensive!
your right about the fulness of sound..
i sort of think of it as a balanced sound..
quad esl57 sum 'balanced' up for me, they are rolled off at the top and bottom end but still sound good..
Bass and rolled off treble or vice versa is not 'balanced'
thats the issue with many lowther cabs.. not enough bass.... not 'balanced'
its hard getting bass drivers to match lowthers. but it is possible going down the vintage route... many 12" hi guass paper cones sound just like lowthers...all of the same era really..
i get quite deep bass around 30-40 hz in room,.. real bass.. and a very solid sound because of that, very detailed and fast too and no box resonance or horn colour that people think is deep bass but is not..
.. very different to most lowther single full range set ups, to me ..it sounds 'right' now..
the only thing i would add is i use old triodes in my amps
the bass is always deeper than the popular new production tubes
the baffles are efficient.. more volume than the horns..
steve
OB's seem to fill in the gaps in all the right places and unearth hidden mid and treble information. On some CD's the fullness gets a little bit much. but that IMO is more than made up for by the many "good" CD's they enhance.
I am using two 12" units in addition to Fostex 206E's (in Sigma 208 cabs). I am using a BSC circuit and an additional tweeter. The OB's are powered actively at 90Hz.
I am using two 12" units in addition to Fostex 206E's (in Sigma 208 cabs). I am using a BSC circuit and an additional tweeter. The OB's are powered actively at 90Hz.
Godzilla said:
It is not easy to do. You usually have to fool around with it a lot
to get what you want, and maybe not even then.
That electronic crossover usually absorbs a bunch of detail or "magic" that we hear when the amp is connected directly to a driver. Some of us here won't tolerate a baffle step circuit (yes it helps in the bass but we just lost a bit of detail).
When the quality of a cap is heard, imagine what 10 opamps in an active crossover (even 1) let alone more coupling caps, more power supply noise, and another ground plane.
But we want our bass !!!!!!!!!!!
What do we do ?
A friend said " yea, people like the full range thing until they want more full range." Now we add a super tweet here, a bass module there, now we have a 3 way, but at least is does most of what we like. Most of info from one driver. Still a compromise but many different ways to get to your goal. We lost a bit of resolution but now don't hide from our pink floyd, madonna, or symphony music anymore.
We havn't made a driver yet that is super quick and zero harmonic distortion, let alone its own non linear distortion. Shoot, even a notch filter can smooth the response but ears can still hear a bit of ringing, and that ringing mixes with other frequencies causing their +/- frequencies to ring, all measurable.
Even the jbl 4430's can sound blurry (gargling). That is a 15" crossed at 800hz. My 3 way vegas (15") made the trumpet sound like they were gargling when playing "battlestar galactica" original theme on telarc's time warp cd. I couldn't figure out what was happening. I added an electonic crossover (100hz 24db LR) and the trumpets stopped gargling. Oh yea, it went wicked loud too !!!!!!!!
Norman Bates
When the quality of a cap is heard, imagine what 10 opamps in an active crossover (even 1) let alone more coupling caps, more power supply noise, and another ground plane.
But we want our bass !!!!!!!!!!!
What do we do ?
A friend said " yea, people like the full range thing until they want more full range." Now we add a super tweet here, a bass module there, now we have a 3 way, but at least is does most of what we like. Most of info from one driver. Still a compromise but many different ways to get to your goal. We lost a bit of resolution but now don't hide from our pink floyd, madonna, or symphony music anymore.
We havn't made a driver yet that is super quick and zero harmonic distortion, let alone its own non linear distortion. Shoot, even a notch filter can smooth the response but ears can still hear a bit of ringing, and that ringing mixes with other frequencies causing their +/- frequencies to ring, all measurable.
Even the jbl 4430's can sound blurry (gargling). That is a 15" crossed at 800hz. My 3 way vegas (15") made the trumpet sound like they were gargling when playing "battlestar galactica" original theme on telarc's time warp cd. I couldn't figure out what was happening. I added an electonic crossover (100hz 24db LR) and the trumpets stopped gargling. Oh yea, it went wicked loud too !!!!!!!!
Norman Bates
I have come to the conclusion that you can't get it all from one driver. More drive units, matched correctly = effortless musicality.
Steve's baffles with their EX4s & vintage Goodmans woofers are a major a culture shock to people used to more conventional hifi. Would everyone like it? Nope. I do, but then, I'm a heretic without much time for a lot of the hifi conventions anyway. They are indeed about as far as you're likely to get from most systems, although that also has a lot to do with his amplification, & while they don't do everything, they make up for it elsewhere.
Actually, I can see the EX series having their uses on baffles as that damped back-plate, which is there to limit midrange / HF output to the rear of the cone to help some of the dodgier horns, should also come into play. Dipole upper mids & treble = not such a great thing, at least in my experience. YMMV of course. The EX units are worth the extra over the DX, at least IMO, but not generally; it's app. specific. Resonant box? DX = way to go. Horn, BL or otherwise? I'd take the EX. Baffle? Again, I'd probably take the EX, but it might be worth experimenting to see which you prefer the cover. The proximity of the room boundaries will also have a lot to do with that.
Actually, I can see the EX series having their uses on baffles as that damped back-plate, which is there to limit midrange / HF output to the rear of the cone to help some of the dodgier horns, should also come into play. Dipole upper mids & treble = not such a great thing, at least in my experience. YMMV of course. The EX units are worth the extra over the DX, at least IMO, but not generally; it's app. specific. Resonant box? DX = way to go. Horn, BL or otherwise? I'd take the EX. Baffle? Again, I'd probably take the EX, but it might be worth experimenting to see which you prefer the cover. The proximity of the room boundaries will also have a lot to do with that.
norman bates said:
With an electronic crossover, the amp is directly attached to the driver.
Personally, I don't use op amps in active crossovers. I can get the job
down to a single JFET with no feedback with less effort and cost.
Dialing in the amplitude and phase is the headache. Many times the frequency
response is flat but the phase response is off in the crossover area, screwing
up the transient information.
😎
norman bates said:
I have experienced that. Our latest experiments with PLLXOs has been very fruitful thou -- and that with parts that were jut lting around
dave
Nelson Pass said:
I'm basically sold on the idea of fullrange + big woofer in an OB. How did you manage the phase so far? In my case the distance between FR and woofer coil is about 85mm. Tried to correct it using allpass phase correction, but not happy. Next is to try physical (acoustic) alignment.
I'd only use a 24db LR crossover, slide drivers back and forth till match up for time alignment.
Based on my needs and experimenting, I need one 6.5" to run mid/highs crossed 200hz @ 24db.
To me, a 6db isn't steep enough, a 12db is 180 oop, an 18db can work only if it falls on a natural 6db rolloff for a 24db acoutic rolloff.
here is a link of textbook 24db LR.
I assume since phase is exactly opposite, it is always in phase, even around the crossover point.
http://techtalk.parts-express.com/showthread.php?t=205553
I'd read the highs are shifted 1 cycle, I'm not sure how audible that is.
The truest way would be to do a shootout between 2 active crossovers exactly the same except one is 6db and the other 24db.
I'd been looking at the passive line level crossovers for a while.
The marchard 24db seems good for $80 a module. But you need a beefy output from preamp.
Norman
Based on my needs and experimenting, I need one 6.5" to run mid/highs crossed 200hz @ 24db.
To me, a 6db isn't steep enough, a 12db is 180 oop, an 18db can work only if it falls on a natural 6db rolloff for a 24db acoutic rolloff.
here is a link of textbook 24db LR.
I assume since phase is exactly opposite, it is always in phase, even around the crossover point.
http://techtalk.parts-express.com/showthread.php?t=205553
I'd read the highs are shifted 1 cycle, I'm not sure how audible that is.
The truest way would be to do a shootout between 2 active crossovers exactly the same except one is 6db and the other 24db.
I'd been looking at the passive line level crossovers for a while.
The marchard 24db seems good for $80 a module. But you need a beefy output from preamp.
Norman
norman bates said:
Hi Norman.
Can I suggest that this is because the rise in driver impedance at its fundamental resonance allows much greater cone excursion and output than a humble series capacitor value would otherwise suggest is possible.
A crude but lossy 8 ohm resistor connected across a nominal 8 ohm voice coil is of significant assistance in improving the LF roll-off without further degrading the phase response, and this applies to both widerange and supertweeter connections. Indeed I find that this damping resistor actually improves the phase response and assists OB woofer/widerange integration.
Further improvement of woofer/widerange integration is possible by using EQ and/or driver Q lift below the room/OB roll-off frequency combined with natural driver roll-off plus a single choke (ONLY) above, to match the capacitor roll-off on the mid. A Zobel across the driver may also be used to limit mid frequency output with rising driver impedance, but the direct connection of a capacitor across the woofer voice coil has always introduced a tonality within the crossover region for me !!!
Besides using a choke plus capacitor to roll-off the woofer introduces greater phase lag where the drivers should be 'blending' at crossover, than does a single series choke/Zobel plus additional boost below the baffle roll-off frequency to acheive a similar SPL response.
In other words I find woofer lift below baffle/room frequency plus 6dB/oct cut above, to provide a more phase coherent woofer/widerange resultant than can optimising the driver with the baffle and then applying 12dB/oct or more cut to the woofer.
Further, my transformer 'T'-bass circuit does this, and as a result I will never be returning to other methods of LF crossover or enclosures for my lounge listening again, though of course suitable drivers must be chosen at outset. The component values used can also be adjusted to compensate for first half cycle dynamic loss due to driver mass/Qes, but I am not going into that here for those who do try the circuit will hear for themselves exactly what I mean.
I have not been doing any audio for a couple of months now, but I will redraw a representative 'T'-bass circuit and post it here.
Cheers ......... Graham.
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