Here is a good example of a FAST design, and might be a very good suggestion for to be the diyAudio reference speaker:
FAST build with Alpair 7.3 and Seas L26ROY and Hypex AS2.100
Ok, so skip the very fancy cabinerty, but the design is simple enough, and considering the quality of drivers used, when optimised, it should sound awesome. Just my $0.02.
Enjoy,
Deon
FAST build with Alpair 7.3 and Seas L26ROY and Hypex AS2.100
Ok, so skip the very fancy cabinerty, but the design is simple enough, and considering the quality of drivers used, when optimised, it should sound awesome. Just my $0.02.
Enjoy,
Deon
I am inclined to agree with you, but the XO needed for the P-13 combination is much more difficult to design and optimise (just ask Lynn). My suggestion is for a speaker that will be relatively foolproof and muck less sensitive to XO parts quality (considering it is to be active). Amp are not hard to make- something like the inverted gainclone. Or just buy a pair of Hypex 30w modules.
Enjoy,
Deon
Hypex shop
Hypex UcD34MP 4 x 30w module
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It is interesting that Chris had a P13 + D27* system to start our team back over a decade ago. The P13 & 2 pair of the tweeter are here somewhere collecting dust due to many more satisfying speakers.
* (and that modded to considerably better than stock)
dave
I am inclined to agree with you, but the XO needed for the P-13 combination is much more difficult to design and optimise (just ask Lynn). My suggestion is for a speaker that will be relatively foolproof and muck less sensitive to XO parts quality (considering it is to be active). Amp are not hard to make- something like the inverted gainclone. Or just buy a pair of Hypex 30w modules.
Enjoy,
Deon
Hypex shop
Hypex UcD34MP 4 x 30w module
Yes but not all speaker builders are amp and EXO builders (I ain't for sure) so this was always going to be a passive project I think.
It is interesting that Chris had a P13 + D27* system to start our team back over a decade ago. The P13 & 2 pair of the tweeter are here somewhere collecting dust due to many more satisfying speakers.
* (and that modded to considerably better than stock)
dave
They may indeed exist Dave but I haven't heard any of them, I live in a speaker builders wasteland here. I have heard a few good big ones when living in Melbourne but for most people a good 8inch full range is a little expensive
There have been many suggestions to go with bipole (push/push?) particularly in difficult rooms.
My problem is that I don't have a clear idea of how to achieve this.
Does the cabinet volume double
With drivers facing out (front & back) are they wired out of phase?
Is there a consensus of whether 1 or 2 tweeters are preferred?
I have the Vifa drivers.
My problem is that I don't have a clear idea of how to achieve this.
Does the cabinet volume double
With drivers facing out (front & back) are they wired out of phase?
Is there a consensus of whether 1 or 2 tweeters are preferred?
I have the Vifa drivers.
For a bipole read this.
The TLb -- Introduction
I don't know if bipoles help with difficult rooms and maybe a 2.5 way could be an option. Either way, with the driver sets wired in parallel, the impedance will halve and fall below 4 ohm which could be a problem for some amplifiers. If that's the case, then bi-amping would be required. For a 2.5 way, a 3.9mH - 5.6mH (DCR 0R6 max) inductor would be required for the 0.5 woofer and the tweeter resistor may have to be lowered depending on taste.
Volume does double to 19 litres and the port would need to be increased in diameter (68mm min) to decrease chuffing. For a 68mm port, the length would be 66mm to achieve similar tuning but with dual woofers a lower Fb would be better..... use 80mm-90mm in length.
The drivers would be wired in phase.
The TLb -- Introduction
I don't know if bipoles help with difficult rooms and maybe a 2.5 way could be an option. Either way, with the driver sets wired in parallel, the impedance will halve and fall below 4 ohm which could be a problem for some amplifiers. If that's the case, then bi-amping would be required. For a 2.5 way, a 3.9mH - 5.6mH (DCR 0R6 max) inductor would be required for the 0.5 woofer and the tweeter resistor may have to be lowered depending on taste.
Volume does double to 19 litres and the port would need to be increased in diameter (68mm min) to decrease chuffing. For a 68mm port, the length would be 66mm to achieve similar tuning but with dual woofers a lower Fb would be better..... use 80mm-90mm in length.
The drivers would be wired in phase.
The Tlb uses front and back tweeters which is why I asked the question. Others have told me that using only one gives a more coherent sound stage and have even suggested that for bipole the tweeter should be on the back in cases where front speaker is running full range (PW13H).
Any thoughts?
Two further questions arise from your earlier response.
If the bipole arrangement eliminates the need for BSC then is there some min/max width/depth that can not be exceeded for this to work?
Your idea for a 2.5 is not something I had considered before. By bi-amping, did you mean two separate amplifiers or independent wiring from a single amplifier? Would I use the the same crossover on the mains that you suggested for your last iteration? Does this include BSC?
Thanks for your input. The road ahead is gradually getting clearer.
Any thoughts?
Two further questions arise from your earlier response.
If the bipole arrangement eliminates the need for BSC then is there some min/max width/depth that can not be exceeded for this to work?
Your idea for a 2.5 is not something I had considered before. By bi-amping, did you mean two separate amplifiers or independent wiring from a single amplifier? Would I use the the same crossover on the mains that you suggested for your last iteration? Does this include BSC?
Thanks for your input. The road ahead is gradually getting clearer.
A bipole needs both tweeter and woofer on front and back. A speaker with 1 tweeter cannot be a bipole and that's why I suggested a 2.5 way.
BSC is basically a function of the baffle width but with a bipole or a 2.5 way, the second woofer gives back what is lost by the front woofer so baffle width is not critical.
Bi-amping means 2 power amplifiers per speaker so 4 channels for a stereo speaker or 2 stereo amps. The crossover for a 2.5 way would be:
The TM (2-way part) see post #392 http://www.diyaudio.com/forums/multi-way/25590-diyaudio-reference-speaker-project-20.html#post3198613
The 0.5 woofer see post #408 gives automatic BSC.
A bipole would need a different crossover all together and none of mine would work so see the TLb.
BSC is basically a function of the baffle width but with a bipole or a 2.5 way, the second woofer gives back what is lost by the front woofer so baffle width is not critical.
Bi-amping means 2 power amplifiers per speaker so 4 channels for a stereo speaker or 2 stereo amps. The crossover for a 2.5 way would be:
The TM (2-way part) see post #392 http://www.diyaudio.com/forums/multi-way/25590-diyaudio-reference-speaker-project-20.html#post3198613
The 0.5 woofer see post #408 gives automatic BSC.
A bipole would need a different crossover all together and none of mine would work so see the TLb.
Now that my diyAudio P13WH reference speakers are broken in (ten plus years of daily music's gotta count as broken in, right?) I thought I'd measure them.
First photo shows the measurement setup. The position on my desk is pretty-much as I have them on the bedside tables - about 10cm from the wall.
Next plot is with an AEM6000 derived amp. This thing is flat from 5Hz to 100KHz +/-.1dB, so makes a good reference. The bass is... lacking. It gets much worse when I pull it away from the wall.
Next with my NAD3020B, which has been sitting by my bedside driving these speakers for pretty-much the whole time I've had them. Despite building a pile of super-duper low-distortion, incredibly flat, super low noise MOSFET amps, I've stuck with this one for driving these speakers, despite the hum and hiss.
Now I know why. It's lack of flatness (bass and treble controls are mid-way) EQ these speakers rather well.
The final plot shows a comparison between the two amps.
First photo shows the measurement setup. The position on my desk is pretty-much as I have them on the bedside tables - about 10cm from the wall.
Next plot is with an AEM6000 derived amp. This thing is flat from 5Hz to 100KHz +/-.1dB, so makes a good reference. The bass is... lacking. It gets much worse when I pull it away from the wall.
Next with my NAD3020B, which has been sitting by my bedside driving these speakers for pretty-much the whole time I've had them. Despite building a pile of super-duper low-distortion, incredibly flat, super low noise MOSFET amps, I've stuck with this one for driving these speakers, despite the hum and hiss.
Now I know why. It's lack of flatness (bass and treble controls are mid-way) EQ these speakers rather well.
The final plot shows a comparison between the two amps.
Attachments
Has it really been that long?
I never actually built them, in the end I used the drivers in a big closed bass 3-way using a P26 woofer.
The big woofer did add the missing bass obviously but I've not found the mid/treble combination lacking.
Now that I have time on my hands and spare drivers on the shelf I really really should build a pair
I never actually built them, in the end I used the drivers in a big closed bass 3-way using a P26 woofer.
The big woofer did add the missing bass obviously but I've not found the mid/treble combination lacking.
Now that I have time on my hands and spare drivers on the shelf I really really should build a pair
Ghost of speakers past
Thanks for posting the measurements Suzy. Not too bad and I'm happy with that as I've seen a lot worse. The xo, with 3 components, seems to be doing it's job. The distortion values are higher than I expected and in particular H3, but you tend to get higher H3 than H2 in speakers. At least there is not huge variations in distortion over the operating range. Yep, bass is MIA. If you need more top end you can always drop the resistor to the next lowest value.
Ted, if you are going to build one of these, use the 9.5 litre design as it has a better tonal balance with more bass. It relies heavily on boundary loading and mine were 40mm from the wall.
The 5.2 litre design is very low on bass and is bettered easily by a little 2.5" PC speaker design I'm doing at the moment using a SB65WBAC25-4 in a 1.4 litre vented enclosure. I'm going to build it in a 100mm PVC pipe 45° elbow and is designed for 5W only as I'm using a T-Amp (DTA-1 or DTA-2). Nearfield, this is plenty loud. I've added a pic of the prototype.
I got into this micro stuff after I was looking at the UE and JBL Bluetooth thingies for the workshop and they sounded terrible. Easily bettered by some small speakers and T-amp hooked up to an iPod.
Thanks for posting the measurements Suzy. Not too bad and I'm happy with that as I've seen a lot worse. The xo, with 3 components, seems to be doing it's job. The distortion values are higher than I expected and in particular H3, but you tend to get higher H3 than H2 in speakers. At least there is not huge variations in distortion over the operating range. Yep, bass is MIA. If you need more top end you can always drop the resistor to the next lowest value.
Ted, if you are going to build one of these, use the 9.5 litre design as it has a better tonal balance with more bass. It relies heavily on boundary loading and mine were 40mm from the wall.
The 5.2 litre design is very low on bass and is bettered easily by a little 2.5" PC speaker design I'm doing at the moment using a SB65WBAC25-4 in a 1.4 litre vented enclosure. I'm going to build it in a 100mm PVC pipe 45° elbow and is designed for 5W only as I'm using a T-Amp (DTA-1 or DTA-2). Nearfield, this is plenty loud. I've added a pic of the prototype.
I got into this micro stuff after I was looking at the UE and JBL Bluetooth thingies for the workshop and they sounded terrible. Easily bettered by some small speakers and T-amp hooked up to an iPod.
Attachments
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I'm keen on doing a 4" + 3/4" in a TL next. There's a whole flock of nice 4" (120mm flange) midwoofers to choose from, for not a lot of money, and they can be shoved up close to a 19mm dome. Say SB12NRX25 + ND20FB. My experience with the Ariels and with the noisePlank TG9 has me very keen on little drivers with transmission lines. I reckon the 4 + 3/4 TL would be very nice for my desk, and a whole pile stacked on top of one another would be fun.
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The SB12NRX25-4 is a great driver and have used it in 2 speakers. An MTM with a SS S2905 and Jeff Bagby's Soprano with a slightly modified crossover. The bass performance is great for a 4" driver. In fact, SB Acoustics drivers are very good and are now my driver of choice. Great performance for the dollar.
Look like one of a set of Q Acoustics 2010i's, an off the shelf speaker, with their own drivers.
Q Acoustics 2010i Compact Bookshelf Speakers Pair
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Correct. There are details on this speaker and later in the thread, driver details.
Sometimes building a budget small speaker is not worthwhile
Sometimes building a budget small speaker is not worthwhile