I found this MTM design the other day.
It uses 2 Scan Speak 18W8531G00 Drivers and a D2905/9900 HF unit.
Having seen a lot of bad press for the !8W8531G00 n 2.5 way speakers what do you think of this design and crossover which I believe is set at 1800hz.
I notice that the HF unit is not offset does that matter and also the bass units are widely spaced.
It uses 2 Scan Speak 18W8531G00 Drivers and a D2905/9900 HF unit.
Having seen a lot of bad press for the !8W8531G00 n 2.5 way speakers what do you think of this design and crossover which I believe is set at 1800hz.
I notice that the HF unit is not offset does that matter and also the bass units are widely spaced.
I note the XO was done in X-Over 3 Pro, which notwithstanding the name is a rather (make that highly) limited piece of software that takes no account of driver phase relationship, offset etc. It looks like they may have tried to compensate for step loss a bit, but those transfer functions appear to be bald mathematical curves derived from the driver T/S parameters rather than measured acoustic data (default for that software, albeit you can import a measured FR, minus phase). So as a design, I would be wary. It might be good, but I would want to see the measurements.
The drivers however are excellent. The 9900 is still one of the best soft-dome tweeters on the market (and if anybody wants to put it as their No.1 I wouldn't argue the toss, ever 3 decades after it was first introduced), and the midbass is also very good -excellent motor, reasonably smooth, extended response, fairly straightforward to work with.
The drivers however are excellent. The 9900 is still one of the best soft-dome tweeters on the market (and if anybody wants to put it as their No.1 I wouldn't argue the toss, ever 3 decades after it was first introduced), and the midbass is also very good -excellent motor, reasonably smooth, extended response, fairly straightforward to work with.
IIRC, during the great days I heard this tweet in the Hansen Prince Loudspeaker... very very good indeed.
Maye this worths a look & read for the op : Zaph|Audio - ZD5 - Scan Speak 15W8530K00 and Vifa XT25
One of the rare pass band time delayed tweeter design avialable 🙂
Maye this worths a look & read for the op : Zaph|Audio - ZD5 - Scan Speak 15W8530K00 and Vifa XT25
One of the rare pass band time delayed tweeter design avialable 🙂
I'd be very interested to read any bad press on that driver. Was it specific to 2.5 way designs??
I have a very similar 4 ohm version and I am extremely pleased with the results, but have not attempted a 2.5 design. Outstanding in a 2-way.
I have a very similar 4 ohm version and I am extremely pleased with the results, but have not attempted a 2.5 design. Outstanding in a 2-way.
As I recall one person posted here couldn't get on with it. I don't off-hand remember any others though.
Is there anyone here who has the ZAPH ZRT2.5 who is pleased with it.
As I remember System 7 felt that crossover was not right.
As I remember System 7 felt that crossover was not right.
That's because Steve's personal mantra is to not xover so low. That's his beef alone here.
The issues with the 2.5way were related both to a maligned tuning and xover that did not match the drivers being used. It might be that the supplied parts were incorrect out of the box, or that the drivers' parameters had changed since the design John created was designed.
I've known of at least one person who had to redesign his bass tuning, and the xover had swapped resistor values for the Lpad.
Later,
Wolf
The issues with the 2.5way were related both to a maligned tuning and xover that did not match the drivers being used. It might be that the supplied parts were incorrect out of the box, or that the drivers' parameters had changed since the design John created was designed.
I've known of at least one person who had to redesign his bass tuning, and the xover had swapped resistor values for the Lpad.
Later,
Wolf
I haven't build the ZRT2.5, and I don't have a direct experience with it. However John Krutke (Zaph) has personally built and listened to every speaker he designed. His measurement and designing abilities were very good, and all his designs are very well documented in every aspect, he always provided simulation and measurement. So I'd trust that the ZRT2.5 is a good design, and frankly wouldn't listen to someone that isn't able to show a measurement and don't use real measurement data in his simulations.
The limitation of the ZRT2.5 is fully described in the Zaph page, and is inherently of every 2.5 way design, needing a large room.
Reading the Wolf's post above, the Zaph design is from 2008, and last checked in 2010, I don't know if the drivers used in the design have changed in 10 years.
As for the Solen kit, I wouldn't touch it, as it seems to be designed with a simple crossover calculator, and I don't trust a kit that doesn't show a measured or at least a simulated response. BTW this is a 2 way design and not a 2.5 way.
Ralf
The limitation of the ZRT2.5 is fully described in the Zaph page, and is inherently of every 2.5 way design, needing a large room.
Reading the Wolf's post above, the Zaph design is from 2008, and last checked in 2010, I don't know if the drivers used in the design have changed in 10 years.
As for the Solen kit, I wouldn't touch it, as it seems to be designed with a simple crossover calculator, and I don't trust a kit that doesn't show a measured or at least a simulated response. BTW this is a 2 way design and not a 2.5 way.
Ralf
The solen kit seems to have chosen a zero bafflestep design (very low value series woofer inductors). The nominal driver sensitivity is 87dB. Doubling up drivers gives you 93dB - but then you will lose 3 - 5 dB bafflestep.
I'd avoid.
I'd avoid.
TBH I would like to build the Zaph ZRT2.5 but am a bit nervous.
I do not have a really big room but I was intending to build it as a sealed box.
Also I would probably reduce the baffle step a little but not sure if this could be done.
I do not have a really big room but I was intending to build it as a sealed box.
Also I would probably reduce the baffle step a little but not sure if this could be done.
That rather obviates the point of using a 2.5 setup then. It was a good project when John designed it; it's possible that the drivers have changed a bit since as has been noted. Since you're already talking about modifications, I'd be inclined to consider an alternative project better suited to your requirements. We can no doubt make some useful suggestions if you can provide a bit more information on what you're aiming to achieve, system, room etc.
Hi Wolf --
Ahhh, I don't know why but talking to a professional speaker maker and others, it does seem like some of the 6.5" (18W) SS Revelator drivers are very different than spec'd, mostly in a good way, the high end measures much better, less tricky, than the spec sheets. My source said SS confirmed this was true.
I have hypothesized that there was an undocumented manufacturing change, but of this I have zero confirmation. It's just a working theory. My singular pair of them were of the "good" and "not to spec" variety.
Ahhh, I don't know why but talking to a professional speaker maker and others, it does seem like some of the 6.5" (18W) SS Revelator drivers are very different than spec'd, mostly in a good way, the high end measures much better, less tricky, than the spec sheets. My source said SS confirmed this was true.
I have hypothesized that there was an undocumented manufacturing change, but of this I have zero confirmation. It's just a working theory. My singular pair of them were of the "good" and "not to spec" variety.
This is what JK said about the ZRT2.5:
If you don't have a large room then build the ZRT 2 way, there is also an option for reducing the baffle step compensation, so you can tweak to your taste.
And this about tuning:
And from the blog:
Ralf
I am looking for a sealed mtm or 2 .5 design.
I have a 12 inch sealed sub but dont want to use all the time and want decent bass without it.
Room is about 6m x 3.5m.
I listen about 2.5m from speakers which are very close to the 6m wall but not in corners
I have a 12 inch sealed sub but dont want to use all the time and want decent bass without it.
Room is about 6m x 3.5m.
I listen about 2.5m from speakers which are very close to the 6m wall but not in corners
That is not a very big room and with speakers and you relatively close to a wall the 2-way design should fit. The 2.5-way really has to get off the wall at least 1m and your ears too.
I was looking at DIYAudio.pl they have some MTM and 2.5 way designs that look interesting with SB17 drivers just wonder how good the crossover designs are.
Some do not have any resistors is this unusual.
Some do not have any resistors is this unusual.