phase

watchemglow · « **on:** 9 Jun 2009, 02:01 am »

Who's still lovin' their 938s out there?

In light of Peter Moncrieff's review of the 968s, I wonder if anyone has tried reversing the phase to the midrange driver of their 938s.

I have.

cheers,
Paul

gogg · « **Reply #1 on:** 13 Jun 2009, 10:24 pm »

Hello!

I am new owner of a 938 ( last 6 months ) and saving money for amp to do the job with 938.
My KRELL KAV-400xi just could not drive them correctly so i sold it.
I had a few other amps that also sucked.

Inverting the phase of any driver in 938 was not better in my situation.

Must say I enjoy 938's even without matching amplification.
Really special loudspeakers but needs carefull matchig of components and wires.

What are youre impressions?
Why did you asked that question?

P.S. English is not my language so excuse me.

ndeslions · « **Reply #2 on:** 16 Jun 2009, 10:05 am »

Best match for the 938 i heard so far : the Lavardin amps, especially the IT model.
I'm an Hyperion dealer but not a Lavardin dealer, i tried maybe 20-25 amps with the 938 and 968.
Try to hear one and you will "see".

gogg · « **Reply #3 on:** 16 Jun 2009, 12:11 pm »

Thank you very much for that information.

watchemglow · « **Reply #4 on:** 18 Jun 2009, 12:53 am »

Hi Gogg,

I'm surprised you Krell had trouble driving the 938's. They have a reputation for being easy on amplifiers, so I wonder what issues you had with the sound. You say that you still enjoy the 938's - but lots of amps that sucked... have you had these speakers working in a good set up yet? I just wonder if the amps are really your problem. That said, you're not likely to go wrong with Lavardin. I hope you sort it all out.

Speaking of sounds that suck, literally, and referring back to phase issues again. While I've always enjoyed my 938's, I always felt that Srajan's 6moons review was spot-on in describing them as very pure, but a bit like viewing from a distance, a great panoramic vista that didn't necessarily make you part of the musical experience. I often found vocals slightly recessed in the mix... clear, but not necessarily projecting the energy out to me. Then recently I was listening to a CD and found one voice in particular sounded evacuated and concave, exactly along the lines described in the IAR review of the 968.

So I switched the midrange phase and this has completely changed the balance. Voices have distinctly more body and tighter body, energy is projected properly. It makes you want to sing along - I'd always wondered why these speakers never had that effect on me before. Instruments are far more cohesive from top to bottom. A plucked string on an acoustic guitar presents all the internal elements from treble to bass in a cohesive way. The speakers are nearly invisible; many veils have been removed. Singers are 'be there' clear, there's great immediacy. It sounds much more correct to me.

Of course, I could be getting phase issues introduced upstream, but I don't think so. I'm still playing around with how the bass should be set with respect to the midrange polarity - there may be some thinness in the upper bass with standard connection, but connected either way the bass is more tonal now and much easier to follow.

The good thing is that this is really easy to try. I'd love to hear from anyone else who gives it a go - assuming they're happy with their amp in the first place of course.

ndeslions · « **Reply #5 on:** 18 Jun 2009, 01:16 pm »

Quote from: gogg on 16 Jun 2009, 12:11 pm

Thank you very much for that information.
My close friend will soon become official Lavardin dealer and i'll be first around to listen to those amps!

Have you any other advice (expirience) about 938 , not exposed at this forum, to share with me and every body else? ( i'm tired of experimenting and need a little break so anything is good to me )

Ask your friend to get the Lavardin cables (speakers and interconnects) as they match very nicely with both Hyperion and amps.
If you can listen to this setup please write your impressions in this forum

gogg · « **Reply #6 on:** 19 Jun 2009, 01:40 pm »

Ok guys thak you both.

Problem with my 938s is little too slow bass.
When I figure out where exactly the problem is i'll be back here to inform you.

Dracule1 · « **Reply #7 on:** 28 Jun 2009, 08:34 pm »

Gogg, I've found two primary reasons for slow bass of the 938s are due to amplification and room interactions.

Watchemglow, you reversed the phase of your midrange of the 938s? The crossover topologies for the 938s and 968s are different as far as I'm aware, 968s being closer to first order. I'm not aware the midrange phase is reversed for the 938s. I have not found the 938 presentation distant - IME the presentation had lot to do with the amplification used.

watchemglow · « **Reply #8 on:** 29 Jun 2009, 12:18 pm »

Hi Dracule,

Yes, I have the midrange reversed, and the bass too. I haven't analysed the bass too closely, but it seemed to follow the IAR discussion on the 968s in that, with midrange reversed but bass correct, the upper bass/lower mids seemed a little lean. Right now, it really does sound good. Vocal energy just seems to come at you straight up off the singers' diaphragms. Instruments have resolved into a tighter and more coherent image. I've had my 938s configured normally for over 3 years, so it is a bit shocking to find something so fundamental only now. Its also surprising that it is not more obviously incorrect one way or the other. Those two sentences may seem contradictory, but of course, subtle audible differences can be hugely important musically.

As I said, it could be something upstream in my system, but that is not my suspicion. I was aware that the 938s and 968s have different crossovers, but I think (I haven't checked back to confirm) that the 968 review indicated the element causing the phase inversion was there to overcome a resonance in the midrange driver. Perhaps this element also exists in the 968s - I don't know. Bottom line is that, for many, it should be easy to try for themselves. If so, give it a blast. Should some folks come to the same findings, I expect some might still prefer the straight wiring. Its a bit like a setting for different voicings.

Hi Gogg,

About 6 months back I finally managed to resolve, or at least markedly improve upon, a long standing issue I had with my household electricity mains supply. This improvement to power quality led to the most significant improvement in bass (and just about everything else) that I've been been able to achieve. Some Boston Audio tuneblocks under my CD transport also made a great improvement to bass. My first serious system a few years back had big issues with slow bass which were resolved by swapping out the dreadful Cardas Cross interconnects for some (awesome) Cawsey CCAs.

George47 · « **Reply #9 on:** 3 Sep 2009, 09:33 pm »

Guys,

This subject has been debated but what is the current thinking on changing the polarity of the mid-range speakers? Is it specific for the 968, is it something the manufacturer has a view on? What is people's experience? I could (and probably will) play with polarity as the speakers are tri-wired but what does Hyperion think?

watchemglow · « **Reply #10 on:** 4 Sep 2009, 06:36 am »

As per prior post, I have my speakers reversed for mid and bass. It certainly seems to be working for me but the post didn't seem to spark much interest and I don't think many others have tried it (nor felt the need to). If you're tri-wired, as I am, it is extremely easy to try as I'm sure you're aware. If you have a recording that you find sounds thin and 'sucked out', see if reversing the polarity gives you better body and projection. Conversely, if you have a recording that you feel already has those qualities then see if the change is detrimental. I believe some folks who have the benefit of a phase switch in their system will move back and forth for different recordings. I haven't observed any negatives, but the benefits have been more obvious on some recordings than others.

Sadly, the folks at Hyperion are not inclined to share their thoughts on the circle here. I don't know if there is any percieved conflict in manufacturers doing so. I would be interested to know if they agreed with the phase reports for the 968 and if they made any changes as a result of that review.

RCduck7 · « **Reply #11 on:** 4 Sep 2009, 11:47 am »

Quote from: ndeslions on 16 Jun 2009, 10:05 am

Best match for the 938 i heard so far : the Lavardin amps, especially the IT model.
I'm an Hyperion dealer but not a Lavardin dealer, i tried maybe 20-25 amps with the 938 and 968.
Try to hear one and you will "see".

I drive my 938's with a Dussun V8i integrated, power enough but anyone heard them or used these speakers on a Dussun?

George47 · « **Reply #12 on:** 4 Sep 2009, 08:48 pm »

Hmmm. ...

I contacted the importer and they said they prefer them connected as per the back of the speaker with no phase inversion. I will try it over the week-end.

watchemglow · « **Reply #13 on:** 5 Sep 2009, 12:18 am »

Importer? Which country may I ask?

James Romeyn · « **Reply #14 on:** 5 Sep 2009, 03:42 am »

Does the OEM wire all drivers in phase? Such speakers are more revealing of absolute polarity than non-phase coherent speakers (one or more drivers wired in reverse polarity to others).

Phase coherent speakers will have the above described negative audio performance symptom if/when their polarity is reversed (relative to the original musical event in real time). FYI there is only limited adherence to absolute polarity in the recording/software chain; further, dubbing can & will sometimes reverse the absolute polarity.

All above is preface to this recommendation: for any/all phase coherent speakers, if/when the recessed negative performance symptom is observed, reverse the input wires of BOTH speakers, thus reversing the absolute polarity. The result may be revealing. (Unbalanced analog components require an extra distortion-increasing gain stage to reverse polarity-not recommended.)

Just curious if 6moons shared an opinion of the audibility or lack thereof regarding absolute polarity? Did they notice a relationship between audibility & the speaker's phase-coherency?

George47 · « **Reply #15 on:** 5 Sep 2009, 12:05 pm »

Quote from: watchemglow on 5 Sep 2009, 12:18 am

Importer? Which country may I ask?

Real Hifi in the UK. They are still plugging the speakers, although not sure what direct selling will do. They also advertise it as a 938 UK voiced speaker.

So far the speakers sound really lively and fast with correct wiring. With reverse polarity the voices are more solid but some of the liveness goes and on some tracks sound slightly odd (hollow). if you want a very lively sound then leave well alone but for more solid voices then change the polarity. More listening required.

RCduck7 · « **Reply #16 on:** 5 Sep 2009, 10:59 pm »

Quote from: George47 on 5 Sep 2009, 12:05 pm

Quote from: watchemglow on 5 Sep 2009, 12:18 am
Importer? Which country may I ask?

Real Hifi in the UK. They are still plugging the speakers, although not sure what direct selling will do. They also advertise it as a 938 UK voiced speaker.

So far the speakers sound really lively and fast with correct wiring. With reverse polarity the voices are more solid but some of the liveness goes and on some tracks sound slightly odd (hollow). if you want a very lively sound then leave well alone but for more solid voices then change the polarity. More listening required.

I am from Belgium and i also bought them in my country.
Wether they are UK voiced or not, i don't know, it might be a mod from the "Real Hifi" importer only.
But it's intresting, maybe i should contact "Real Hifi" and ask them.

watchemglow · « **Reply #17 on:** 6 Sep 2009, 10:08 pm »

Good to hear your impressions George47, I was wondering how the 'UK Voicing' might play into the phase question. I'd love to know what the importers have done and what they were out to achieve with this re-voicing.

watchemglow · « **Reply #18 on:** 6 Sep 2009, 10:13 pm »

By the way, did you try reversing the bass along with the midrange. Not doing so, in my case, did result in an odd, unbalanced sound, in line with the notion that some regions of the spectrum could be cancelling out.

RCduck7 · « **Reply #19 on:** 14 Sep 2009, 11:06 am »

I have an answer from Real hihi in the UK...

"Hello Danny,

American speakers always sound over-endowed in the bass when one listens to them over here. Our UK rooms are typically smaller and our walls are made from more solid materials. We do modifications to the crossover to adjust certain parameters.
I am not familiar with Belgium acoustic environments and I?d hate to charge you for a modification that might make your sound worse rather than better.

I am very sorry that I can?t help you any further.

Best regards,

Matthew Jameson"