By the time you have added a tweeter that would end up serious $$$ by normal DIY standards but ought to be rather good if implemented properly 😀
Who do I need to goad to build a pair...
Who do I need to goad to build a pair...
It's only a couple hundred (US) dollars more than using the PTT4 as a midrange. 🙂
On the other hand, I checked the distortion plots again and it looks like HD is around 50 dB below fundamental for the Volt, while it's more like 65 for the PTT4. For now, I think I'll wait for a Purifi midrange.
On the other hand, I checked the distortion plots again and it looks like HD is around 50 dB below fundamental for the Volt, while it's more like 65 for the PTT4. For now, I think I'll wait for a Purifi midrange.
Whats up with the 4db 900-2500 low Q dip in the PTT04? Is that the high walls of the surround having a waveguide/detrimental effect on the output or what?
better the VM752 vs ptt4....
btw not bad the 2"
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Were they measured the same way (volts watts meters baffles etc), I found it very difficult to establish this.
Has any one actually sorted this out?
Has any one actually sorted this out?
Yes for me with my limited knowledge this is where the trouble starts - my present mid is the Eton 3-400 (I believe discontinued) again I am not convinced I have access to data for that driver that is well enough defined. So for THD I can not compare Purifi to Volt to Eton. Here I am only guessing, but with these values being so small I would have thought differences in test could radically changes these values.
Sealed PTT 6.5?
Somewhere I read (and cannot find it again, not sure which forum) folk were exploring using the Purifi in a sealed box and rolling it off at about 90 -100 hz and using a sub up to that point.
Can anyone enlighten me on how that went?
It is attractive in that it will be a very small enclosure and should have very good power handling but very solid performance down to what ever crossover frequency is chosen. What is the current thinking of this path and has anyone done it? If so how did it go?
Somewhere I read (and cannot find it again, not sure which forum) folk were exploring using the Purifi in a sealed box and rolling it off at about 90 -100 hz and using a sub up to that point.
Can anyone enlighten me on how that went?
It is attractive in that it will be a very small enclosure and should have very good power handling but very solid performance down to what ever crossover frequency is chosen. What is the current thinking of this path and has anyone done it? If so how did it go?
Onslo,
I'm in the process of making a sealed enclosure, using 2 Purifi 6.5 (both in parallel, one on front baffle, one on rear in reverse phase). I want to compare this Purifi design to an OB design that uses a 5" MR + a 12" down to 80Hz (both designs transition to a subwoofer at 80Hz).
I was in contact with Purifi (they were extremely nice), and they recommended using 12 L sealed enclosure per driver. This should give a Qt of ~0.6 and an Fs of 59Hz (if 20L/driver is used, Qt decreases to ~0.5 and Fs to 50Hz). This can be verified using VituxCAD. I'm planning on using ~27L for 2 drivers (with the excess accounting for bracing, X/O and driver volume).
They felt that a sealed box design will work much better with a subwoofer than using a PR approach since the 5th order system with a zero at the PR resonance is very difficult to cross over to a subwoofer.
If no subwoofer is to be used, then they recommend using 2 Purifi 6.5 PR per 6.5 driver, in a volume of 12 to 20L per driver, depending on the preferred alignment.
I'm in the process of making a sealed enclosure, using 2 Purifi 6.5 (both in parallel, one on front baffle, one on rear in reverse phase). I want to compare this Purifi design to an OB design that uses a 5" MR + a 12" down to 80Hz (both designs transition to a subwoofer at 80Hz).
I was in contact with Purifi (they were extremely nice), and they recommended using 12 L sealed enclosure per driver. This should give a Qt of ~0.6 and an Fs of 59Hz (if 20L/driver is used, Qt decreases to ~0.5 and Fs to 50Hz). This can be verified using VituxCAD. I'm planning on using ~27L for 2 drivers (with the excess accounting for bracing, X/O and driver volume).
They felt that a sealed box design will work much better with a subwoofer than using a PR approach since the 5th order system with a zero at the PR resonance is very difficult to cross over to a subwoofer.
If no subwoofer is to be used, then they recommend using 2 Purifi 6.5 PR per 6.5 driver, in a volume of 12 to 20L per driver, depending on the preferred alignment.
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When I finally get around to working on my design (summer 2021, perhaps?), I intend to either use my PTT6.5s in an OB or a sealed configuration. Either way, I'll cross over to a CSS SDX12.
I run the 6.5 in a 5lit sealed box - use dsp to nudge it up at the bottom end then let it role off naturally. Cross over at about 50 to a pair of 10 inch peerles xl drivers.
Thanks Jasdiy. When you say 'roll off naturally' are you meaning at the top? Or do you mean at the bottom after your equalisation is applied?
Also have you measured it to see that there is no hole in the 50-80hz area?
Sounds like a good implementation. It would be interesting to hear more about your project. What tweeter and crossover at the top and how it integrates with the Peerless sub.
How much of an issue is this likely to be in reality as you will be well down in the modal region of most normal rooms?