I am considering a new build where the target is a set of high-end bookself speakers for my livinroom of about 4x4m. I have read a lot of good things about the Purifi 6.5" drivers and had the idea to get inspired by their SKP5 kit with the Mundorf AMT and external crossover so I have the option to go active later on.
But what other alternatives is there for drivers that is worth mentioning if price is not a problem? Of cause price and quality should add up but if you could pick anything you wanted for a bookshelf like this, what would you choose?
Im looking for at set that can stand alone, so work without a sub while having a neutral and balanced sound.
But what other alternatives is there for drivers that is worth mentioning if price is not a problem? Of cause price and quality should add up but if you could pick anything you wanted for a bookshelf like this, what would you choose?
Im looking for at set that can stand alone, so work without a sub while having a neutral and balanced sound.
The midbass is very nice and the best driver for this application but the overall speaker is let down by the AMT:
Purifi SPK5 Speaker Review (Prototype) | Audio Science Review (ASR) Forum
I would use this tweeter with price no object:
http://www.bliesma.de/Datasheet T34B-4.pdf
Its worth noting that if you can cope with a larger box then you can outperform the Purifi driver by simply using two cheaper drivers and going 2.5 way. Its only the best driver if your space constrained.
Purifi SPK5 Speaker Review (Prototype) | Audio Science Review (ASR) Forum
I would use this tweeter with price no object:
http://www.bliesma.de/Datasheet T34B-4.pdf
Its worth noting that if you can cope with a larger box then you can outperform the Purifi driver by simply using two cheaper drivers and going 2.5 way. Its only the best driver if your space constrained.
I haven't heard these, but the designers are highly regarded, I've built speakers by both gentlemen:
Paul Carmody's DIY Speaker Pages - Carrera
Speaker Design Works
Geoff
Paul Carmody's DIY Speaker Pages - Carrera
Speaker Design Works
Geoff
Curt is an experienced designer no doubt about that and scan-speak drivers are excellent, what are you going to drive them with the 2-way Invictus spkrs running at 83dB efficient?
High powered and high quality sounding amps are normally very expensive.
There is XRK971's Bookshelf TL Purifi build well documented on this forum. Also worth a look it Jeff Bagby's last (AFAIK) offering the Helios, he also stated that it was his best - SB Satori WO24P woofer, Passive radiator and SB Be dome in a wave guide (SB TW29BNWG). Kits are available for the Helios (Meniscus) or details on the Facebook DIY Loudspeaker Project Pad.
However, these are probably more stand mounts than book shelf so depends on what is an acceptable size.
However, these are probably more stand mounts than book shelf so depends on what is an acceptable size.
What I mean with bookshelf, is the same as stand mounts, in Denmark we don't really use any other terms than bookshelf to describe none-floor standing speakers. So they don't have to be small. The one I am looking at now with the Purifi unit is about 15L but my first alternatives would be a used pair of Dynaudio Contour 20 which is significantly bigger.
I would like to keep the amplifier out of the equation, my first idea was to use my Naim Atom as amp with an external passive filter. Later on I would do an active filter with a 4ch DIY amplifier to match the speaker.
I have seen a lot of people using the Be drivers for their projects, how do they compare to "standard" metal tweeters? I feel like a lot of the both DIY and brand speakers i have heard with metal domes have a tendency to be exciting but also tiresome and harsh over longer listening sessions.
I would like to keep the amplifier out of the equation, my first idea was to use my Naim Atom as amp with an external passive filter. Later on I would do an active filter with a 4ch DIY amplifier to match the speaker.
I have seen a lot of people using the Be drivers for their projects, how do they compare to "standard" metal tweeters? I feel like a lot of the both DIY and brand speakers i have heard with metal domes have a tendency to be exciting but also tiresome and harsh over longer listening sessions.
Be is the 'perfect' material in domes this size the breakup frequency (where the dome stops acting as a piston) is pushed beyond 20 kHz. With other metal dome materials the breakup frequency can be below 20kHz and cause a harsh sound due to poorly damped resonances. Fabric domes also breakup (and even lower in frequency than metal domes) but they have generally better internal damping. IMO if Be was not expensive it would be by far the most widely used material.
This is by far the best Purifi woofer implementation i've seen so far - expensive though because it uses 2 passive radiators per cabinet
Puri Bliss - BeWg | HiFiCompass
Puri Bliss - BeWg | HiFiCompass
It depends on the room size, how loudly you want to play music and what you listen to; the maximum volume at Xmax is estimated at 97dB, or about the same as some TM designs with the popular Dayton RS180. That's about the same noise level as my lawn mower at 1m.
However, if you listen to say Verdi's Requiem or Beethoven's Ninth Symphony so that the quieter parts are clear, you could well run out of headroom when they get loud: the "Dies Irae" in the Requiem will wake the neighbours!
Geoff
I've heard these and they are the best bookshelf speakers. Yesterday-today.
And the best thing is: You don't need an extra tweeter for 20Khz which you cannot hear anyway.
Western Electric WE KS-14703 755A Speaker in Original WE Cabinet
Western Electric KS-12046 - YouTube
And the best thing is: You don't need an extra tweeter for 20Khz which you cannot hear anyway.
Western Electric WE KS-14703 755A Speaker in Original WE Cabinet
Western Electric KS-12046 - YouTube
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That just means you aren't objective enough and reading some blah blah can change your mind. I look at the measurements, i do not read text.
As for passive crossover not being high end - i'd like to see that claim substantiated by double blind test or some scientific white paper. Otherwise it is just your opinion and i tend not to read those as well.
Sure a passive crossover is subject to distortion caused by:
1) Impedance of drive units altering with drive level
2) Non linearity of the components that make up the crossover
3) Hysteresis of components that make up the crossover
4) Microphonic sensitivity
4) Parameter shift of crossover components due to heating
Furthermore its not possible to realize a linear phase crossover (whether this is audible is debatable but its certainly more 'ideal') or steep crossover slopes that better reduce out of band distortion from drivers (over excursion breakup etc). Taking into account the considerable limitation of passive crossovers and the ability to do better for decades, why would they be considered high end?
I don't see the measurements on that page to comment on the design of the crossover hence why I used the words. I would need to see individual driver responses (including crossover), distortion vs level plots and polar plots of the completed speaker. I only see on axis responses and the raw driver responses. I'm not saying the speakers crap just that the crossover section alarmed me.
1) Impedance of drive units altering with drive level
2) Non linearity of the components that make up the crossover
3) Hysteresis of components that make up the crossover
4) Microphonic sensitivity
4) Parameter shift of crossover components due to heating
Furthermore its not possible to realize a linear phase crossover (whether this is audible is debatable but its certainly more 'ideal') or steep crossover slopes that better reduce out of band distortion from drivers (over excursion breakup etc). Taking into account the considerable limitation of passive crossovers and the ability to do better for decades, why would they be considered high end?
I don't see the measurements on that page to comment on the design of the crossover hence why I used the words. I would need to see individual driver responses (including crossover), distortion vs level plots and polar plots of the completed speaker. I only see on axis responses and the raw driver responses. I'm not saying the speakers crap just that the crossover section alarmed me.
at 83dB eff, you really an AMP enough to drive to a reasonable level, I won't even use a 50watter, the sound dynamics is not there.
I use a 15watter(tube) to drive an 88db driver, the sound dynamics is not there and just adequate. I don't listen to high volume. Before then I use a 35watter(Chipamp) to drive a 89dB driver then you will find that is adequate..
We can agree to diagree.
I have made an initial design idea with a cabinet constructed from stacked plywood layers, enabling me to make the footprint of the speaker from partial elliptic shapes to reduce internal standing waves in the horizontal plane. An angled plate will be added inside the cabinet to break standing waves in the vertical direction.
Since I intend to place the speaker on a stand, but also are required to place the speaker relatively close to the back wall I was thinkin of placing the port at the bottom of the speaker instead of the back. This would give me the longest distance to the closest surface in the direction of the port, and I would not have to sacrifice to much of the original box shape to fit a flared port on the back.
Would this idea be worth moving forward with? or would I get less port noise by keeping the port on the back side, with the consequence of the port being closer to the back wall?
Since I intend to place the speaker on a stand, but also are required to place the speaker relatively close to the back wall I was thinkin of placing the port at the bottom of the speaker instead of the back. This would give me the longest distance to the closest surface in the direction of the port, and I would not have to sacrifice to much of the original box shape to fit a flared port on the back.
Would this idea be worth moving forward with? or would I get less port noise by keeping the port on the back side, with the consequence of the port being closer to the back wall?
Hi Kurt,
The port in the bottom of your box is a good alternative for speakers on stands. I have realised it in a small 11-liter prototype on stands and it works very well, no problems at all, and you´re not directly exposed to any midrange emmisions from the tube. And it looks very clean, too...
Good luck with your build!
Mattes
The port in the bottom of your box is a good alternative for speakers on stands. I have realised it in a small 11-liter prototype on stands and it works very well, no problems at all, and you´re not directly exposed to any midrange emmisions from the tube. And it looks very clean, too...
Good luck with your build!
Mattes
1) That is the same with active systems. When voice coils heat up, impedance changes.
2) Don't use crappy components. Bennic caps, Jantzen air coils and ceramic resistors will do.
3) Only problem if you use cored inductors of very bad quality. Saturation and hysteresis then may be the problem but i've got this covered in 1) Use Jantzen C coil, ERSE or Sledgehammer and you're good to go.
4) Unless you use coils that are not dipped in varnish and do not glue components to the crossover boards. You've gotta know what you're doing.
5) Again, don't use crappy components. If you use 5W resistor where 20W is needed, it is not resistor's fault. If your inductor is heating, it is not inductor's fault.
As with passives, dsp actives (and i'm not at all against it, i use hybrid approach) demand knowledge to be able to make a successful design. There are cases where DSP and multichannel amps are justified - very low crossover points in three ways or SBIR speakers like Kii3, D&D 8C, Beolab 90 etc. But for conventional loudspeakers DSP is not a neccessity. Use one dsp and one amplifier channel to correct some irregularities if there are any to begin with and thats it.
About bolded one, you've answered on your claim.
About underlined - steep filters in passive are easilly made 36dB/о оr 48dB/о. Google Richard Modafferi crossovers. What do you think Magico and Joseph Audio are doing ? If you need steeper than that, you are using the wrong drivers beyond their intended purpose. Overexcursion protection is done in my computer using Foobar or JRiver, You do not need DSP and 6 channel amplifier to protect your speakers from overexcursion.
I still don't see any considerable limitation of passive crossovers apart from that it is easier to implement it by DSP. "Harder" does not mean "lesser quality".
There are off axis as well, up to 60 degrees without any visible aberation in frequency response - which i can not claim for version with Mundorf AMT. But i do agree that more thorough measurement would be nice.
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And how do you proceed to correct for constant time delay? Proceed to angle the baffle?
You mention the linearity is great if you use quality parts. The parts you mentioned measure to about 0.2% distortion. This is orders of magnitude larger than the one of a good quality amplifier. Let alone something like the purifi amplifiers.
Also, even if you use 20W resistors instead of 5W, they still have a thermal drift. For high frequencies this doesn't matter, because the temperature will remain constant. For low frequencies you get thermal modulation effects.
I'm not sure how expensive those crossover components are, but you have a Fusion amplifier for about 330 euro for the 2 way version. That also includes amplification and DAC. Seems like a very reasonable price compared to amplifier+DAC+fancy crossover components.
Besides if OP is developing his own speake as opposed to a DIY kit, I doubt he will get it perfect in the first try. Developing crossovers in digital domain is much easier to adjust.
You mention the linearity is great if you use quality parts. The parts you mentioned measure to about 0.2% distortion. This is orders of magnitude larger than the one of a good quality amplifier. Let alone something like the purifi amplifiers.
Also, even if you use 20W resistors instead of 5W, they still have a thermal drift. For high frequencies this doesn't matter, because the temperature will remain constant. For low frequencies you get thermal modulation effects.
I'm not sure how expensive those crossover components are, but you have a Fusion amplifier for about 330 euro for the 2 way version. That also includes amplification and DAC. Seems like a very reasonable price compared to amplifier+DAC+fancy crossover components.
Besides if OP is developing his own speake as opposed to a DIY kit, I doubt he will get it perfect in the first try. Developing crossovers in digital domain is much easier to adjust.
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