Andrew Jones MoFi Speakers

[Axo1989]

Oh man, this reminds me of the many instances I've had with people around my high end speakers!

Most normal people aren't really used to expensive audio gear, or seeing speakers as anything but some utilitarian object in the home. Typical of this, a few years ago I'd just received and set up my Joseph speakers - probably the most expensive speakers I've ever owned and which have a gorgeous polished-to-perfection finish.

A cable guy showed up and had to figure something out in my listening room. I left him in there, in a bit he calls me in to talk to me and I walk in - he's placed all his tools - pliers, exacto knife, screws and other things, on top of one speaker and he's leaning with his hand on the other one to chat with me!

Mortified seeing all those tools on the oh-so-easy-to-scratch top of the speakers I had to quickly ask him to be careful of the speakers and not place anything on them. He was pretty baffled.

A similar thing happened just recently when I had a very non-audiophile acquaintance help me put on some new isoacoustic footers on my Thiel speakers. First thing he did was put a bunch of tools on top of the speakers.

I've guests put their drinking cups or beer bottles on the speakers.

Then there's the time a little kid held my Hales center channel speaker hostage at a party...

Haha, so true. A flat surface at convenient height is totally tempting. Humans are bad enough, the true disappearing act of my Codex is that glass-covered speakers become entirely non-interesting to a hyper-active pair of Abyssinian felines.

 

[Sal1950]

I've guests put their drinking cups or beer bottles on the speakers.

I know but I got to think "how fricken stupid can you be, you see this incredible beautifully finished work of art and put your crap on it" ??? You just really want to give them a slap. Some crude MF'in people just have no respect. And then they gripe at a car show cause the owner puts ropes around them to keep the monkeys away.

 

[MattHooper]

I know but I got to think "how fricken stupid can you be, you see this incredible beautifully finished work of art and put your crap on it" ??? You just really want to give them a slap. Some crude MF'in people just have no respect. And then they gripe at a car show cause the owner puts ropes around them to keep the monkeys away.

Ok...now I've gotta mention to you the kid story with my HT gear.

Years ago we had a gathering of families...I think it was a birthday party. Many of the kids were quite young and my home theater/2 channel listening room was full of equipment, so I'd closed the curtains to the room.

At one point I was walking by the room, noticed the curtains had been opened, and there was a young boy...maybe 6 or so...standing in front of my projection screen reaching out to touch it. It's very hard to deal with any damage/smudges on a quality projection screen! So I gently asked him not to touch the screen please, and...how about coming back and joining everyone else? He looked at me with a grin and reached out to touch the screen again. As he did so he was leaning in to my expensive (and at the time almost impossible to find) center channel speaker below the screen, by his knees. I quickly asked him to please be careful of that speaker and...hey..why don't you come out of the room? He looked down at the speaker in front of him, looked at me again with a grin, then pulled back his leg to kick the speaker - foot poised in the air, aimed at the front of the drivers. "No, no...please don't...that's very expensive...please, just move away from the speaker and come back to the kitchen..."

He jerked his leg several times toward the center channel"fake" kicking the speaker, almost punching in the drivers, while smiling at me, enjoying torturing me. What could I do? Wasn't my kid. In fact I didn't even know which family he belonged to. And if I took the time to leave him there and find his parent to get him, who knew what he'd do? So I was stuck for a while with the speaker 'held hostage' me trying to talk him out of the room. After a while he got tired of the game and left the room.

Little bundles of joy aren't they?

I don't imagine that scene would have lasted as long if this happened in your place, Sal ;-)

 

[cavedriver]

I've guests put their drinking cups or beer bottles on the speakers.

Every time I look at the still-excellent finish on the tops of my Snells I remember all the beer cans and bottles that have been placed on top of them, however briefly, before I could insert a coaster or remember to add a cover for that particular event.

 

[Sal1950]

I don't imagine that scene would have lasted as long if this happened in your place, Sal ;-)

AMEN, I would have dragged him out of there by his ear.

 

[DSJR]

I remember submitting myself to a demo by a true-believer Linn dealer. I approached it partly with an open mind, and partly as an "afternoon at the zoo". I think the hauling in and out was performative and very well calculated. It lengthened the gap between auditions, harming audio memory; it allowed plenty of time for explicit coaching to set up expectation bias ("Now you'll hear how ... "); and it produced dependency on & gratitude toward the poor guy huffing and puffing and wrestling. It was smart. For the record, I thought the little ones (Kan?) were bad, the middle sized ones (Sara?) were OK, and the big ones (Isobarik?) were awful.

I only liked Kans when they were firing down a long room, where bass modes 2/3 the way down brought some bass back. Saras were funky reproducers of rim shots with a 50Hz or so bass peak in our dem room.. Isobariks in passive form varied with the room and particular pair as consistency wasn't so good apart from the early MDF ones from mid 1983 to end of 1984 after which KEF shagged the B110 mid driver (I owned three pairs of 'briks covering 1979 in teak veneered chipboard, 1984 walnut MDF and a disastrous black pair dating from 1985. I didn't like the revised versions of these of the late 80's as colourations became evven more marked once the attempts to flatten the response showed it up. Everything after that in the 90's seemed to be maximising profits using plastics, cheap far eastern drive units and all but hobbling the passive versions so they cou'ld 'upgrade you' to the actives (I owned late Keilidh's for a while and they were floor-standing 'loudness switches' until you went active with them!).

 

[Vacceo]

Ok...now I've gotta mention to you the kid story with my HT gear.

Years ago we had a gathering of families...I think it was a birthday party. Many of the kids were quite young and my home theater/2 channel listening room was full of equipment, so I'd closed the curtains to the room.

At one point I was walking by the room, noticed the curtains had been opened, and there was a young boy...maybe 6 or so...standing in front of my projection screen reaching out to touch it. It's very hard to deal with any damage/smudges on a quality projection screen! So I gently asked him not to touch the screen please, and...how about coming back and joining everyone else? He looked at me with a grin and reached out to touch the screen again. As he did so he was leaning in to my expensive (and at the time almost impossible to find) center channel speaker below the screen, by his knees. I quickly asked him to please be careful of that speaker and...hey..why don't you come out of the room? He looked down at the speaker in front of him, looked at me again with a grin, then pulled back his leg to kick the speaker - foot poised in the air, aimed at the front of the drivers. "No, no...please don't...that's very expensive...please, just move away from the speaker and come back to the kitchen..."

He jerked his leg several times toward the center channel"fake" kicking the speaker, almost punching in the drivers, while smiling at me, enjoying torturing me. What could I do? Wasn't my kid. In fact I didn't even know which family he belonged to. And if I took the time to leave him there and find his parent to get him, who knew what he'd do? So I was stuck for a while with the speaker 'held hostage' me trying to talk him out of the room. After a while he got tired of the game and left the room.

Little bundles of joy aren't they?

I don't imagine that scene would have lasted as long if this happened in your place, Sal ;-)

Being a teacher and having to deal with little humans like that on a normal basis (well, mine are teenagers), what typically works for me is the "don´t mess with the long-haired, black-clad, Deicide shirt-wearing dude".

AMEN, I would have dragged him out of there by his ear.

I can picture you with a face taken from Eastwood´s Gran Torino.

 

[Tangband]

I never did forensic analysis on this aspect (so 90% of you would dismiss my comments out of hand) but the sonic issues were repeatable and easy to hear if you knew the room and some of the speakers listened to. Drive units are designed to vibrate at audio frequencies and I'd posit that not all are well loaded mechanically or electrically and may just be more easily excited, especially in bass frequencies. Back in the 80's we went stupid on this and would have nothing to do with comparators and walls of speakers as I started with, so forgive the knee-jerk when I spied several quite large loudspeakers all grouped and/or stacked together when you're trying to audition a speaker for purchase. One way kind-of round it is to place speakers not in use face down on the floor, or maybe facing a side or back wall. Someone somewhere I hope may well have done response and impulse measurements to see what happens. It can't have just been a silly ploy by Linn as we peeps demonstrating had to lug often large boxes in and out of the dem room

No, it wasnt a ploy. If you have an acoustic guitar stucked between your speakers the same blurring of the pitch when listening to music will appear , as If you would have 10 passive loudspeakers in the same room. Its subtle, but enough to disturb the perceived pitch . A grand piano in the same listeningroom are terrible.

Another reason Linn did single speaker dem. was for an even more important reason : as you know , each loudspeaker from linn ( or any other brand that was sold by the linndealer ) had one exact spot in the dealers listeningroom where they sounded the best. Dealers often used tape to mark the exactly right placement in the room for different models , after using tunemethod ( listening for the clearest melodypitch in the bass area ) to install each pair of speakers correctly.

This was important in the demonstration because customers could come in with whatever loudspeaker they had, to compare it to a Linn speaker, and the customers speakers were randomly put up in the room and it was clear for everyone that Linn made the best speakers in the world.

Still today, there are almost no knowledge in the usual hifistores how to install a pair of speakers in a room , for best pitch accuracy. Noone seems to have a clue of how music works. This is one of the big reasons for Linns success as a brand.

 

[al2002]

Ok, the latest Stereophile just arrived. The MoFi measures very well. There is a very slight rise in the treble, could be left alone if you have old ears or eq’ed to taste. If I were in the market for a set of under 4 k speakers these would certainly make my short list.


The new active Dynaudio 10 is also reviewed in the same issue.

 

[cavedriver]

From measurements it seems the treble rise is over 5 dB at 20k and less at 10k but still significant. The interesting thing was that the off-axis response was much smoother, like really good from 2k all the way to 20k and without the rise. Based on this I will now be playing with keeping the speaker axes 15-25 degrees off from the listener's ears and see if I can still get a satisfying stereo image.

 

[Dennis Murphy]

From measurements it seems the treble rise is over 5 dB at 20k and less at 10k but still significant. The interesting thing was that the off-axis response was much smoother, like really good from 2k all the way to 20k and without the rise. Based on this I will now be playing with keeping the speaker axes 15-25 degrees off from the listener's ears and see if I can still get a satisfying stereo image.

And much thanks to Cavedriver for hauling the 10's over to my house and lugging them inside. I took measurements, which I think are the ones Cavedriver is referring to, and put them through my demo CD paces. I'm hesitant to say much given my status as a competitor. I think I will leave it at: I can see why a lot of people like them, and I don't have any plans to cancel BMR Tower production.

 

[Sal1950]

From measurements it seems the treble rise is over 5 dB at 20k and less at 10k but still significant. The interesting thing was that the off-axis response was much smoother, like really good from 2k all the way to 20k and without the rise. Based on this I will now be playing with keeping the speaker axes 15-25 degrees off from the listener's ears and see if I can still get a satisfying stereo image.

Try both straight ahead, and crossing over a few feet in front of the listener.
Dr Hsu recommends in front of listener for his CCB-8 co-axial.

"The CCB-8s are designed to be toed in so you sit 15 degrees off axis.
i.e., cross the axis of the coaxial drivers about a foot or two in front
of you. This gives the most stable imaging and the widest sweet spot.
The frequency response is also designed to be smoothest at 15 degrees
off axis."

https://www.hsuresearch.com/products/manual/CCB-8manual.pdf

 

[al2002]

From measurements it seems the treble rise is over 5 dB at 20k and less at 10k but still significant. The interesting thing was that the off-axis response was much smoother, like really good from 2k all the way to 20k and without the rise. Based on this I will now be playing with keeping the speaker axes 15-25 degrees off from the listener's ears and see if I can still get a satisfying stereo image.

On axis the region from approx 5kHz to 10 kHz is lifted 2-3 dB, with what looks like a 5 dB resonance, probably related to the coaxial arrangement, at 15 kHz. The full review should be online in a week or two.

 

[al2002]

And much thanks to Cavedriver for hauling the 10's over to my house and lugging them inside. I took measurements, which I think are the ones Cavedriver is referring to, and put them through my demo CD paces. I'm hesitant to say much given my status as a competitor. I think I will leave it at: I can see whey a lot of people like them, and I don't have any plans to cancel BMR Tower production.

Hi Dennis, would you mind posting your FR and directivity measurements here? Enquiring minds and all that…….

 

[Dennis Murphy]

Hi Dennis, would you mind posting your FR and directivity measurements here? Enquiring minds and all that…….

Well, OK, but only because from your description the Stereophile plots seem to track what I got on axis, although JA's main plot is an average of a 30 degree window, which should give smoother results than my strictly on-axis. Further off axis, the 10's measure beautifully. We had the 10's firing straight ahead, which placed my listening position about 15 degrees off axis. So the first arrival would be very smooth. However, my subjective impression tracked the on-axis plot more than the off-axis. This is very unsettled territory. I don't claim to know where truth lies. My measurement software is Praxis, which shifts from anechoic to room mode starting around 300 Hz on down. The big dip below 100 Hz is floor bounce cancellation, which would be present on any stand mount speaker. The peak at 70 Hz is a room mode, very typical of most medium-sized rooms. The response below 70 Hz is garbage--Praxis doesn't have enough resolution down there to give reliable information. We played a series of bass test tones, which indicated the 10's don't have much output below about 40 Hz.

 

[MattHooper]

(From about 200Hz on) That's extremely close to the Stereophile on axis measurements.

 

[al2002]

Than

Well, OK, but only because from your description the Stereophile plots seem to track what I got on axis, although JA's main plot is an average of a 30 degree window, which should give smoother results than my strictly on-axis. Further off axis, the 10's measure beautifully. We had the 10's firing straight ahead, which placed my listening position about 15 degrees off axis. So the first arrival would be very smooth. However, my subjective impression tracked the on-axis plot more than the off-axis. This is very unsettled territory. I don't claim to know where truth lies. My measurement software is Praxis, which shifts from anechoic to room mode starting around 300 Hz on down. The big dip below 100 Hz is floor bounce cancellation, which would be present on any stand mount speaker. The peak at 70 Hz is a room mode, very typical of most medium-sized rooms. The response below 70 Hz is garbage--Praxis doesn't have enough resolution down there to give reliable information. We played a series of bass test tones, which indicated the 10's don't have much output below about 40 Hz.

Thanks Dennis. Ah yes, Praxis, I still have mine stashed away in a closet somewhere. Too bad Bill dId not continue development.

Your curve is a decent match to the Stereophile data above approx. 300 Hz, the 3 kHz dip also appears in S’phile data. Stereophile’s spatially averaged room response was on the bright side due to wide dispersion. I may be in the minority but I’m a big believer in using eq. to fine tune the balance.

Is the 80 Hz dip ready a floor bounce or is it a side/ rear wall effect? IME, floor bounce usually produces dips around 150-250 Hz, depending on the height of the woofers, but then I’ve only measured a few speakers. Were the MoFi speakers on high stands, that might explain the frequency.

 

[Dennis Murphy]

Than

Thanks Dennis. Ah yes, Praxis, I still have mine stashed away in a closet somewhere. Too bad Bill dId not continue development.

Your curve is a decent match to the Stereophile data above approx. 300 Hz, the 3 kHz dip also appears in S’phile data. Stereophile’s spatially averaged room response was on the bright side due to wide dispersion. I may be in the minority but I’m a big believer in using eq. to fine tune the balance.

Is the 80 Hz dip ready a floor bounce or is it a side/ rear wall effect? IME, floor bounce usually produces dips around 150-250 Hz, depending on the height of the woofers, but then I’ve only measured a few speakers. Were the MoFi speakers on high stands, that might explain the frequency.

That's definitely floor bounce. It's lower in frequency than usual, but we had the MoFi on a very tall stand that placed the woofer much higher than the norm. Bill Waslo did move on from Praxis with the OmniMic project he did for Parts Express. However, Praxis remains the best design software I know of because it can automatically adjust for differences in the acoustic center of drivers and the positions of the drivers on the baffle. I would love to buy your Praxis if you want to part with it--particularly the probes PM me if you're interested.

 

[Vladimir Filevski]

You may have done this already, but PLEASE take the other speakers physically away from the pair that are playing, as their drivers will almost certainly be vibrating in sympathy and altering your perception as well as frequency response of the pair playing - and making it more bland/worse.

If multiple speaker pairs must stay in the room while comparing, one simple remedy is to short input terminals on all other speakers which are not playing.

 

[cavedriver]

Try both straight ahead, and crossing over a few feet in front of the listener.
Dr Hsu recommends in front of listener for his CCB-8 co-axial.

Yeah, I read the article about that when it was linked in another thread. I'll also be trying that approach, especially since I have never tested it on any other speaker because I've needed to so I'm very curious what it does to the image and sound quality. I do wonder if any cancellations or decay in sound quality will occur- this is really out of my area of knowledge. Just need to move everything to the other room now so I'm not crowding the speakers. Might have another pair coming tomorrow or next week as well.