• These commercial threads are for private transactions. diyAudio.com provides these forums for the convenience of our members, but makes no warranty nor assumes any responsibility. We do not vet any members, use of this facility is at your own risk. Customers can post any issues in those threads as long as it is done in a civil manner. All diyAudio rules about conduct apply and will be enforced.

Purifi’s PTT6.5W04-01A woofer group buy

Jump to Latest
#84
xrk971 said:
It’s a great woofer and I think any good tweeter that can cross over from 2k to 3k can work well - so it is a matter of taste and budget.

I think my first will be RS28F-4 in a Vistaton WG300 waveguide as that is what I have in a box already.
Click to expand...

are you planning to cross really low, or just try different XO points too see what works well with the woofer?
 
#85
I'm gonna try the Mundorf ribbon used in the demo speaker first, then I may try the BlieSMa beryllium. I also really like the Satori ring radiator and may try that too. Very interested to see what everyone comes up with.
Has anyone modeled these woofers in an MLTL?
 
#88
Group Buy status 3-4-2020

Major milestone, we have confirmation group’s payment of just under $10kUSD has arrived in Purifi’s bank account this securing our place in the production queue. In response to my query about delivery time the answer was:

Currently it looks like we should be able ship in ~10 weeks (if not a slight bit sooner) if the sub supplier deliver as expected. However, until the magnet shipment is secure at our facility I dare not make guarantees given the spreading COVID-19 situation. I’ll keep you informed.​

So, ~10 weeks we are looking at mid-May to early June to land transducers in USA and distribute to group. With this group buy entering the hurry up and wait phase I will post these updates only if news is received from Purifi. I will query them about the critical path magnet supply situation until magnets are in Denmark.

Reviewing our progress the following nine steps for the process were posted January 17th when I announced the GB. We have completed steps 1 to 5 and combined steps 3, 7, and 8.

Done 1. Recruit enough participants to qualify for quantity 8+ pricing.
Done 2. Close participation in initial group buy.
Done 3. Check costs to buy woofers (and passive radiators if anyone orders those) and shipping costs Denmark to Oklahoma, communicate each individual’s total to participants. (Amended to include participants’ 2nd leg shipping costs.)
Done 4. Participants pay using PayPal to group buy organizer. Your PayPal receipt will state “Expected delivery time 6 – 8 weeks”, I will try to beat that, most of that will be determined by Purifi’s build time and shipping including clearing USA customs.
Done 5. When all funds arrive order is placed with Purifi. Be aware Purifi states “Note that this product is made-to-order. Expect approximately 4 weeks delivery time.” (Amended since January 2019 Purifi’s build time estimate increased to ~10 weeks.)
6. While Purifi builds and ship woofers group organizer will prepare boxes and packing for shipping leg within North America.
Done, combined with step 3 7. When shipment arrives in Oklahoma group organizer will break down into shipments to individual participants, determine cost, and communicate to each participant their North American final leg shipping cost.
Done, combined with step 3 8. After participant pays their individual within N. America cost group organizer ships their order.
9. Woofers arrive individual participants’ workshops where they are installed in boxes. Jaws drop, sonic bliss ensues.
 
#92
Norman Tracy said:
January 31, 2020 is the deadline to signup, February 1 I will compute costs and communicate each individual’s total to participants.

This GB is getting great traction, as I write this 8 participants are signed up for 22 drivers and 2 passive radiators.

Some questions and comments….

Jmpsmash asked “Any info on the passive radiator? pros/cons of using PR vs ported for this particular driver.” The Purifi PR’s info is here: PTT6.5PR - PURIFI

As to the pros/cons ported vs passive radiator, with the PTT6.5W04 optimized for such a small (~1/2 cu. ft. 15 liters) vented enclosure, possessing a 30 Hz Fs, and featuring high air moving capacity fitting the port can be tricky. Say we want to tune the box to between 30 to 40 Hz. Looking at the Purifi SPK5 application note they use a 57mm ID port that appears to be about 360mm 14.25 inches long. I write ‘appears to be’ because to fit it in a box with a maximum dimension of 340mm avoiding the woofer and angled shelf brace it has to be bent twice so I am guesstimating the center line dimension. Modeling it I get tuning 37-38 Hz (ok) with port air speeds 47 m/s (ouch) at 200 watts. No wonder in SPK5 they use flairs on both ends of the port. Really cranking it my WAG (Wild A__ Guess) is some port noise will happen. Then again at the 200 watts of input the model shows 108 dB(!) of output at 50 Hz and 100 dB at 30 Hz so a little port noise may go unnoticed. Nevertheless let’s double up use two 5.7 cm ports, same tuning, and 37 Hz F3, with port air speed dropping to ~23 m/s. All good, except now the two port tubes each need to be 766 mm 30 inches long and I need to fit two of them in that 340 x 315 x 240mm box. At this point I start to visualize solutions like a dedicated speaker stand with uprights acting a port tubes or a petite tower with the lower 2/3 housing port tubes.

In contrast use the PTT6.5PR-01A and it’s as easy as build the box and cut holes for the woofer on the front and PR on the back. The PRs also attenuate any midrange noise from inside the box escaping out. Note as is typical the PTT6.5PR has a threaded location for attaching added mass to change tuning frequency. This makes final tuning as easy as listening &/or measuring while adding/removing mass. From the industrial design styling point of view our personal preferences may like what appears to be a second woofer on the box. I find it appears more ‘powerful’ with the second cone. As designer’s let us also check the BOM (Bill of Materials) cost effect. Assuming two of use get PRs on this GB they are $114 each. If I make the vents out of the MDF or plywood I am building the box from or a piece of PVC pipe from the hardware store vent cost is some sweat equity and a few dollars for the MDF/PVC. Personally if it’s a $500 pair of woofers I’m looking for something a bit nicer. I go to Parts Express for that and the Precision Port 2" flared port tube kit is $9.79 each. While on PE a quick check shows non-Purifi brand PRs in the 6 ½ to 10 inch sizes ranging from $11 to $196 each. Interesting to see the cost of a nice flared vent almost the same as entry level PRs.

So two long paragraphs that can be summarized the passive radiator is easier, likely sounds better, and looks better but its 11x the cost of a vent.

Xrk971 asked “Are you guys going to build the reference design (bass reflex with Mundorf AMT) or is anyone considering a more interesting alignment? Perhaps a tapered PMC style TL?” From the verbose answer above I think you can guess I am referencing the SPK5 reference design but going my own way. I lust after the Mundorf AMT but for now will use one of the tweeters from my stock. The TL is an interesting idea. I look forward to seeing, and in some cases I hope hearing, what everyone comes up with. I’m just having too much fun with this.
Click to expand...

I'm fairly new to this and trying to still get my head around design options using Jeff Bagby's Woofer Box Model and Circuit Designer.

I would appreciate some help on what would happen if using the SPK5 port design but with the volume increased from 15l to 20l to accomodate the crossover within the cabinet rather than externally.
 
#93
Hi Norman,
US-Canada border was just closed. We might not be able to pick up the drivers ourselves, but nobody know what happens in the next few months.

There's possibility that we might need to change the second shipping method. We'll see..
Thank you!
 
#94
Group Buy status 3-19-2020

Wow, the unexpected twists and turns of life. My last update was just 15 days ago and COVID-19 was something only effecting PROC and getting electronics from suppliers based there. Now efforts worldwide focus on a pandemic unprecedented in any of our lives. I very much hope that as a first priority you, your family, friends, and work team are healthy and taking best known precautions as the pandemic progresses. In my home Oklahoma USA we have ~60 confirmed cases of C19 out of a population of 4 million. My employer, an industrial electronics manufacturer, remains open unlike churches, theaters, restaurants, bars, gyms, and casinos. I am thankful thus far no one I know has contracted COVID-19 and I can help keep the economy running at the present sadly reduced pace.

Regarding our group order today I shared emails with Purifi and the report is most Purifi staff are working from home but arrangements are in place to keep production running with selected people working at Purifi’s lab/factory. Thus everything is ready when the last parts arrive. Good news is parts shipment is on track and expected to arrive at Purifi first week of April. This will include enough magnets to cover our order.

The above of course assuming Denmark does not declare a country wide lock down as in Italy. I will check back early April to confirm parts arrived as scheduled and the production line remains in operation.

Group buy member racingpht reported yesterday the GB delivery to Canada has a new twist for those who receive packages in USA. Another example of new complexities we face. We will overcome these. We must not just for our passion for HiFi music reproduction but to prime the economies of the world that have provided us the means to pursue such luxuries.
 
#98
Group Buy status 4-14-2020

I hope you are all well as we learn to cope while the pandemic runs its course.

For the North American Purifi transducers Group Buy members I have good news. Purifi reports all components have arrived at their factory/lab and the woofers and PRs for our order are expected to ship end of this week or next. We should temper our expectations in that they also report shipping is taking longer, hardly a surprise given how the pandemic has affected capacity of the global shipping systems.

I will post next update when Denmark to USA shipment of our order is confirmed.
 
You must log in or register to reply here.
Top Bottom