Phase Tech PC 3.1 Speaker Measurements

[uwotm8]

Using a 1.5" mid with a 1" tweeter is honestly a bit weird. A 2" mid + .75" tweeter could achieve a lower woofer crossover point and better high frequency extension.

Back in the days there was endless amount of German 3-way speakers like these

Canton GLX 100 (Gear & Review) - Explorations in Audio

In 2013, not long before our daughter was born, my wife Sabina and I went out to search for a pair of loudspeakers for us to restart our journey in the appreciation of music. When it came to audiophile pleasures, we were both out of practice and felt unsure of what to aim for. Visiting some...

eiaudio.de

Canton, Heco, maybe Saba, Braun and some other.

I only heard one Canton model and it was plain awful, nothing like hi-fi at all. I mean, even Mission 760i were on the next level.

 

[SuicideSquid]

Back in the days there was endless amount of German 3-way speakers like these

Canton GLX 100 (Gear & Review) - Explorations in Audio

In 2013, not long before our daughter was born, my wife Sabina and I went out to search for a pair of loudspeakers for us to restart our journey in the appreciation of music. When it came to audiophile pleasures, we were both out of practice and felt unsure of what to aim for. Visiting some...

eiaudio.de

Canton, Heco, maybe Saba, Braun and some other.

I only heard one Canton model and it was plain awful, nothing like hi-fi at all. I mean, even Mission 760i were on the next level.

Crossing over to a 1.5" "midrange" at 800Hz is certainly a choice.

 

[Yevhen]

An exellent example of what we normally try to avoid: uneven freq response, uneven directivity, high distortion with dominant 3rd harmonic

 

[EJ3]

I personally didn't even know that brand as it was possibly not offered in Europe so I wonder how popular it was in the US, it seems to be from early 00s https://www.soundandvision.com/content/phase-technology-premier-collection-surround-speaker-system

Not very well known here, either.
I had never heard of them, either:
Phase Technology's problem is that they are only sold through a limited number of non-retail dealers (possibly installers).

 

[jkasch]

The foam in the woofers I believe is intended to mitigate high order distortion products. It does technically work but is a bit pointless when the rest of the speaker is a distortion/resonance factory.

I believe the woofer cones are solid styrofoam. I remember examining promotional store samples, years ago.

 

[dbaudio]

I do wonder what kind of condition the crossover capacitors are in.

 

[quocheiser]

I do wonder what kind of condition the crossover capacitors are in.

I was going to write the same thing.

 

[JDS]

These are the measurements of a used/vintage Phase Tech PC 3.1 center speaker. I believe it originally cost US $600. I was kindly sent to me by a member:
View attachment 437589
As you can see, the sample is a crusty one! I must say, I had not seen foam over woofers before. You can rotate the midrange/tweeter assembly as to use the speaker vertically.

Owner told me that this was one of the companies paying attention to directivity as being an important thing. Seeing how it has a mid-range, gives me hope that it delivers on that.

These write-up is rather brief because I am not sure if I have a working sample. I cannot find any measurements of this unit. There is some for the version 2 which looks better.

Phase Tech PC 3.1 Speaker Measurements
Our anechoic frequency response shows clear problem where the mid-range is supposed to be delivering:
View attachment 437590
From memory, the midrange is crossed from 700 Hz. That would in theory fill that hole but maybe they wanted this kind of V shaped response. Besides that, we have a few wide resonances. Directivity is not great causing early window and predicted in-room responses leaving something to be desired:
View attachment 437591
View attachment 437592

As noted, the mid-range should be solving the beaming issue with dual drivers but it clearly is not:
View attachment 437593
View attachment 437594

Vertically of course doesn't have that problem:
View attachment 437595

I was surprised and dismayed that I could clearly hear distortion at 94 dBSPL:
View attachment 437596

View attachment 437597

This is topped by very low impedance:
View attachment 437598

Finally, waterfall shows resonances as we would expect:
View attachment 437599

Conclusions
It should be obvious that this is either a broken speaker or broken by design. I can't be sure which is which. Could have discarded the measurements but after all the work that went into it (including confirming that the midrange was working), I thought I post it anyway.

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I owned a pair of speakers in the late '70s that had foam over the woofers (and the front baffle) -- the Cizek Model Two: https://www.stereonet.com/forums/topic/288890-sold-fs-cizek-model-ii-immaculate-original/

Thought they sounded great at the time.

 

[amirm]

I owned a pair of speakers in the late '70s that had foam over the woofers (and the front baffle) -- the Cizek Model Two: https://www.stereonet.com/forums/topic/288890-sold-fs-cizek-model-ii-immaculate-original/

Thought they sounded great at the time.

Wow, they went nuts putting foam everywhere!

 

[amirm]

We have this unusual, flat distortion peak:

Notice how it hugs the line on the left. I don't think I have ever seen that before. So maybe the foam thing works in which case, one has to wonder why it is no longer used.

 

[DanielT]

Thanks for the test Amir. Phase Tech PC 3.1, rubbish. In the bin with it.

This Phase Tech PC 3.1, how old is it? Thirty years? Things should have happened since then. Speaking of development and with that hopefully improvements see page 4,#89 when AOR (technical developer at KEF) was kind and took the time to compare some different KEF drivers. Interesting, I thought anyway:

Pressed steel speaker chassis vs cast or plastic

OK then - how do you see the sound being transmitted through the system? What are the moving parts? The Voice-coil, cone and dust-cap? How much does all that crap weigh? I cannot imagine that turning a basket out of a billet of aluminium makes sense Surely you can visualise that Sounds...

audiosciencereview.com

 

[Ron Texas]

Years ago I had a pair of their small bookshelves. The foam surrounds rotted and I pitched them.

 

[jomo]

I don't understand reviews like this. By the looks of it, this center channel speaker saw a lot of use. Was is abused? Who knows. But, if it was used daily, it likely needs considerable TLC. From the photos, the fabric dome mid and tweeter are quite faded and dull. They could have pits through the membrane as this is pretty common with fabric dome tweeters >20 years old. I wouldn't doubt the tweeters also need ferrofluid replaced (if they have it) which can be dried up by now. Regardless, these possible issues can ruin the response and significantly increase distortion. And who knows the ESR/capacitance of 30 year old electrolyic capacitors in the crossover network. Were they tested?

What would be an interesting exercise is to explore if there are such problems. Then see if the speaker be improved, with little cost or effort.

 

[amirm]

What would be an interesting exercise is to explore if there are such problems. Then see if the speaker be improved, with little cost or effort.

There is no ROI in spending that kind of energy to do that. As is, a single set of measurements and posting costs about US $2,000 in opportunity cost. I could buy the owner a new speaker than spending that money again on a speaker others are highly unlikely to have.

 

[amirm]

By the looks of it, this center channel speaker saw a lot of use. Was is abused? Who knows. But, if it was used daily, it likely needs considerable TLC. From the photos, the fabric dome mid and tweeter are quite faded and dull. They could have pits through the membrane as this is pretty common with fabric dome tweeters >20 years old. I wouldn't doubt the tweeters also need ferrofluid replaced (if they have it) which can be dried up by now.

There is no sign of "abuse." The tweeter is also working fine. As is, measurements kind of correlate with what is performed on version 2:

 

[kemmler3D]

Yikes. I feel like you could get better sound by picking a speaker completely at random.

 

[jomo]

There is no sign of "abuse." The tweeter is also working fine. As is, measurements kind of correlate with what is performed on version 2:

The Klippel distortion data shows about 5% THD @ 86dB around 1500 Hz and 4.3% THD @ 96dB at the same frequency. I think something is amiss when the distortion reduces as the volume is significantly increased. Since the acoustic transition from the woofer to the mid/tweeter dome is clearly shown in the directivity pattern around 1300 Hz, this says this issue is likely related to the mid dome. Where there is one issue, there are likely more.

 

[beagleman]

I found this, it is essentially the same but a newer version??

Purple trace is the 3.1

The $3,000 Speaker Derby Phase Technology

Phase Technology The other cagey veteran of this speaker group was the Phase Technology system, another prime example of the "if it ain't broke, don't fix it" philosophy. Some of you may be fooled by Phase Tech's relative lack of household-name status into thinking that it's a small company that...

www.soundandvision.com

 

[beagleman]

There is no sign of "abuse." The tweeter is also working fine. As is, measurements kind of correlate with what is performed on version 2:

Amir I believe you are showing the 9.1 response at the top of the page..

Phase Technology Premier Collection surround speaker system Measurements

Measurements The PC 9.1's sensitivity is approximately 88dB/W/m, and its ported cabinet is tuned to about 30Hz. I would rate its nominal impedance at a conservative 4ohms. The impedance bottoms out at 2.64ohms at 123Hz and remains below 4ohms from 80 to 630Hz. Because most program material...

www.soundandvision.com

I found that review and the 3.1 measurement is at the bottom of page I have included it.
The "Huge" off axis dip is what made me realize this is the center speakers actual response!

 

[dasdoing]

I could be dried ou coating (not sure this is the best word): https://www.audiosciencereview.com/...s/tweeter-drying-out.26413/page-2#post-913689