Zumbo: A proposition for you

[zumbo]

I have gotten two emails back from German Maestro stating they should be able to provide the measurements I requested. I didn't get all elaborate like the initial thread post, but we will see.

 

[zumbo]

2/26/11

Zumbo: A proposition for you

2/26/11

Measurements are enough to convince me that they're great overall speakers...perhaps even buy them and sell my own. And not just I, but I think a few on this board. I ask this out of honest curiousity, since you have an obvious love for them.

2/27/11

http://www.german-maestro.de/downloads/test_reports/audio_04_2010_LineaS.pdf

http://www.german-maestro.de/downloads/test_reports/stereoplay_9_09_linea_s.pdf

(EDIT)Found English:
http://www.german-maestro.de/downloads/test_reports/audio_04_2010_LineaS_en.pdf

http://www.german-maestro.de/downloads/test_reports/stereoplay_9_09_linea_s_en.pdf

2/27/11

Bookshelf

http://www.german-maestro.de/downloads/test_reports/audio_07_10_LineaS_B1_en.pdf

2/27/11

sorry, I`ve been on my phone right now nowhere near a computer. Those pdfs are just too small on a 3 inch screen.

Can you not read any of the graphs posted since?

2/28/11

This is older MB Quart Vera stuff. The purple line is the floor-stander, the green line is the center, and the red line is the books. These are 6" drivers.

From the review:
This graph shows the quasi-anechoic (employing close-miking of all woofers) frequency response of the Vera VS 1F L/R (purple trace), Vera VS 1C center (green trace), and Vera VS 1B surround (red trace). All passive loudspeakers were measured at a distance of 1 meter with a 2.83-volt input and scaled for display purposes.

The VS 1F's listening-window response (a five-point average of axial and +/–15-degree horizontal and vertical responses) measures +0.24/–2.20 dB from 200 Hz to 10 kHz. The –3dB point is at 38 Hz, and the –6dB point is at 34 Hz. Impedance reaches a minimum of 8.30 ohms at 216 Hz and a phase angle of –44.66 degrees at 82 Hz.

The VS 1C's listening-window response measures +0.88/–3.71 dB from 200 Hz to 10 kHz. An average of axial and +/–15-degree horizontal responses measures +0.89/–4.55 dB from 200 Hz to 10 kHz. The –3dB point is at 55 Hz, and the –6dB point is at 46 Hz. Impedance reaches a minimum of 5.86 ohms at 205 Hz and a phase angle of –50.97 degrees at 96 Hz.

The VS 1B's listening-window response measures +0.72/–2.96 dB from 200 Hz to 10 kHz. The –3dB point is at 50 Hz, and the –6dB point is at 43 Hz. Impedance reaches a minimum of 4.43 ohms at 1.5 kHz and a phase angle of –53.26 degrees at 96 Hz.—MJP

3/01/11

http://www.german-maestro.de/downloads/test_reports/stereoplay_9_09_linea_s_en.pdf

3/01/11

http://www.mbquart.com/pdfs/press/HifiTest_6_06_Alexxa_S1_en.pdf

 

[GranteedEV]

Just took a look. That HTM (?) graph of the MB Quart Vera shows rather impressive on-axis response with essentially +/-1.5db tolerance in its passband, although it looks very smoothed out so I can't say for sure how reliable it is. Still, that sort of on-axis tolerance for any speaker is extremely good.

The rising response above 15000 hz may or may not sound "odd" especially after room reflections but I personally can barely hear above 15khz anyways so it's not something I would be too concerned over. The top end probably sounds something like a Focal top end, smooth and airy but revealing and perhaps for people who can hear that high, "plastic".

The comments on horizontal listening window response within 15 degrees are nice as they show the speaker probably has a rather nice sweet spot without any head-in-a-vice B.S.. I would like to see some 30, 45 and perhaps 60 degree off axis plots however to see how room-dependant it is. I consider off axis response (more specifically... its uniformity) extremely important because some speakers sound great in some rooms, but the best speakers sound great in most rooms.

The center sounds like your typical MTM center channel speaker that I both look down upon and am stuck with although I'm not sure what exactly it is.

The high impedance is great, although I don't really know enough about its nature to decide wheather I would drive it with a tube. Even a decent solid state amp should drive it however with total ease.

Those other graphs in the PDFs are essentially unreadable even on a computer screen, so I don't know what to say about them.

There's still a lot of information I'd like to see to know where I would rank them but the information we do have dies suggest they're not your typical paradigm type speaker. You've got my interest.

 

[zumbo]

I should have a readable MB Quart QLS 830, and a German Maestro MS F-One shortly. It is at their discretion, of coarse.

The Vera graph posted within the thread is with 6" drivers. It's a 1" titanium dome tweeter.

The QLS are 6.5" drivers, with 1" titanium domes.

The German Maestro are 7" drivers, with 1.6" inverted dome tweeters(Such as Focal).

I honestly look/hope for the earlier QLS to outperform the later Vera. I have no doubt the current German Maestro will outperform both.

After all this is over, I would hope the data will prove what I have been saying since '04 here. You just can't go wrong with a set of QLS 830 for 1k.

I still don't understand how a graph can tell anyone how a speaker sounds. Oh well, glad they did well on them.

I will reply as soon as they send me something. I hope it's not pdf.

 

[KEW]

I still don't understand how a graph can tell anyone how a speaker sounds. Oh well, glad they did well on them.

I don't believe it can in absolute terms, but if the FR was jagged with 10db plus spikes, it is a pretty safe bet it would sound like crap.
I would suspect someone like John Atkinson, who has been measuring (and listening to speakers) forever has a very good idea of how good a speaker is if he can see the whole array of tests like he runs. That doesn't mean he could determine his favorite by the measurements, but I bet he could rule out about 90% without having to listen to them!

 

[GranteedEV]

I still don't understand how a graph can tell anyone how a speaker sounds. Oh well, glad they did well on them.:

The graphs we've seen so far can't really tell us the whole world, although they definitely put the MB Quarts ahead of a good bit of the competition. However two speakers can have identically flat frequency response and sound markedly different. That's because frequency response only tells one part of the story.

A combination of all the graphs I requested at the beginning of the thread however, can get you extremely close to finding a speaker you could live with without hearing it. Sure, we'd all still want to hear it, but it wouldn't be a case of some big issue popping up. It would moreso be the subtle stuff that you'd probably need an A/B test for. If you've got a critically damped speaker with some form of consistent and controlled directivity, flat frequency response, low distortion, high sustained max output/dynamic range, you've got a great speaker. The measurements probably can't tell you what's the greatest speaker, probably because there is no greatest speaker. Speakers by nature are going to be flawed. But I bet you the best speakers measure better than the really good speakers, and the really good speakers measure better than the good speakers, which measure than the mediocre speakers, which measure better than the bad speakers, which still measure better than the awful, grating, unlistenable speakers.

That's because a speaker isn't a subjective instrument. It's an objective tool of reproduction. It's the "flaws" which we perceive as subjective.

 

[zumbo]

So, my assumption was close to correct?

The flatter the line, the better?

And, of coarse, a broader FR is even better.

I personally don't think the height(spl) of the line matters that much. All that can be overcome by more amplifier power. OTOH, I would assume someone shopping for a good set to go with tube amplification would want to see a speaker with a higher line.

 

[zumbo]

I have had a 4/8ohm assumption that I have posted on the forum before, and I never got a response.

I found a thread yesterday on another forum that seemed to clarify my assumption.

A 4ohm speaker will be 3db louder than an 8ohm speaker(equal db specs) on the same amplifier, and at the same numeric/notch/point level of the equipment.

So a 4ohm speaker such as the QLS rated @87db will still be as loud as a 8ohm speaker rated @90db on the same equipment at the same level. However, the amplifier will be working twice as hard. This is where the problem comes in. A more capable amp is needed, and the reward is just incredible.

Do any of you guys know where such an experiment was done?

EDIT Just wanted to clarify that an ohm and db spec of a speaker has just never mattered to me, just as it doesn't with the graph.

The only common link that I find with my auditioning is that the best sounding speakers to me are rated low in either one, or both of the specs.

 

[GranteedEV]

I personally don't think the height(spl) of the line matters that much. All that can be overcome by more amplifier power. OTOH, I would assume someone shopping for a good set to go with tube amplification would want to see a speaker with a higher line.

Two things to note:

1) sensitivity. A more sensitive speaker will have more output at the arbritrary test voltage. since 3db of gain needs double the power, an 86db sensitive speaker needs 200w to be driven to the same levels as a 95db sensitive speaker fed 25 watts. Since 200w will produce more heat, the less sensitive speaker may begin to heat up and lose fidelity at higher volumes. also note that this is particularily affected by distance from the speaker as losses due to distance are significamt in larger rooms!

2)SPL of the frequency response might be flat at lower power, but as you go up in power, how does it maintain mechanical and thermal composure? Does the frequency response sitart to compress and flatten out? Does distortion increase? Do the drivers bottom out? Does the tweeter give out before the midrange? A power compression test and distortion test can tell us much of this.

 

[GranteedEV]

I have had a 4/8ohm assumption that I have posted on the forum before, and I never got a response.

I found a thread yesterday on another forum that seemed to clarify my assumption.

A 4ohm speaker will be 3db louder than an 8ohm speaker(equal db specs) on the same amplifier, and at the same numeric/notch/point level of the equipment.

So a 4ohm speaker such as the QLS rated @87db will still be as loud as a 8ohm speaker rated @90db on the same equipment at the same level. However, the amplifier will be working twice as hard. This is where the problem comes in. A more capable amp is needed, and the reward is just incredible.

Do any of you guys know where such an experiment was done?

Two things:

Sensitivity - measured in db/2.83v/m.
Efficiency - measured in db/w/m

2.83v in 8 ohms is 1w but in 4ohm is 2w because less impedance ('AC resistance') means current can flow more freely. 1w at 4ohm otoh is 2v not 2.83

So if one company states efficiency and the other states sensitivity, the onus is on you to not confuse the two and do a proper conversion.

 

[zumbo]

Two things to note:

1) sensitivity. A more sensitive speaker will have more output at the arbritrary test voltage. since 3db of gain needs double the power, an 86db sensitive speaker needs 200w to be driven to the same levels as a 95db sensitive speaker fed 25 watts. Since 200w will produce more heat, the less sensitive speaker may begin to heat up and lose fidelity at higher volumes. also note that this is particularily affected by distance from the speaker as losses due to distance are significamt in larger rooms!

But, comparing a 4ohm to 8, the 4ohm will be allowing double the current/voltage (not sure which one) to flow from the amp. This should give the 3db increase to the 4ohm speaker at a given numeric/notch/volume level, compared to an 8ohm speaker of equal db(sensitivity) spec.

EDIT. I do believe on amps such as McIntosh you are given different speaker terminals to make connections. This lowers the rail voltage.

So I assume the idea is to lower the voltage input, to allow equal current output.

Their saying is, you pay for 200W, you get 200W.

 

[zumbo]

Sorry, I am an edit junkie.

 

[GranteedEV]

But, comparing a 4ohm to 8, the 4ohm will be allowing double the current/voltage (not sure which one) to flow from the amp. This should give the 3db increase to the 4ohm speaker at a given numeric/notch/volume level.

Returning to my other post earlier, you can't confuse sensitivity with efficiency.

90db/2.83v/m speakers, 4 ohm or 2ohm or 10 ohm, will have identical sensitivity to voltage. The current draw will not remain consistent (putting more stress on the amplifier) but the voltage will be the same. The lower impedance speaker will put more stress but the output will be the same at the amplifier in terms of what the amplifier wants to do (voltage).


So let's take two amps.

One is
25w into 8 ohms
40w into 4 ohms

The other is
25w into 8 ohms
26w into 4 ohms

Not including the other complexities of driving loudspeakers(including that there's no such thing as a flat, resistive load), the reality is

both speakers are capable of 1w into 8 ohms and 2 w into 4 ohms... "2.83v" and will produce the same SPL (90db).

However as you approach the limits of amp B, you'll start to run into problems with the lower impedance speaker, as it will hit its limits with LESS voltage. The higher impedance speaker will continue to ask for more voltage, and will get equally loud with both amps. The lower impedance speaker will much prefer the first amp.


Two 90db/w/m speakers, one 4 ohm and the other 8 ohm, however, are not the same. A better way to look at it would be

4 ohm speaker is
93db/2.83v(2w)/m

8 ohm speaker is
90db/2.83v(1w)/m

Now regarding limiting voltage to get consistant current, it's in one way desirable but it's still dictated by the limits of the amplifier. Limiting voltage mostly just means that if your speaker has key dips, then it won't sound like the part where there's a dip is being compressed and clipping while the part where there's no dip is a lot louder and not clipping.

 

[billy p]

Here is another review I stumbled upon... http://hometheaterreview.com/mb-quart-vera-series-speaker-ensemble-reviewed/

also soundstage did some measurments found here> http://www.soundstagemagazine.com/measurements/mbquart_vera_vs_1f/

Not sure if these speakers were mentioned prior, but I thought I'd share....

 

[zumbo]

Returning to my other post earlier, you can't confuse sensitivity with efficiency.

I am not. I am stating the sensitivity spec given by speaker manufacturers, or one such as the graph posted.

both speakers are capable of 1w into 8 ohms and 2 w into 4 ohms... "2.83v" and will produce the same SPL (90db).

He lies the problem. The spec is given @ 1w 1m whether it is an 8ohm speaker, or a 4ohm.

4ohm speakers are not rated @ 2w 1m.

This is why I believe a 87db 4ohm speaker should be 3db louder than a 87db 8ohm speaker.

Lets say you have two 2-way bookshelf speakers of equal driver number and size. One is 87db 4ohm, and one is 87db 8ohm.

Now lets say said amp is capable to double down. 25w@8ohm, 50w@4ohm.

Turn the volume up half way.

Connect the 8ohm speaker.

Check spl.

Remove that speaker, and connect the 4ohm speaker.

Check spl. Should be 3db higher on the meter.

While I believe this to be fact, I have never tested it. This is why I believe a low sensitivity spec(or graph) of a 4ohm speaker doesn't actually tell the whole story of real world performance, especially when connect to capable amplification.

 

[zumbo]

also soundstage did some measurments found here> http://www.soundstagemagazine.com/measurements/mbquart_vera_vs_1f/

Not sure if these speakers were mentioned prior, but I thought I'd share....

Nice! Those are the Vera that have been posted, but the Soundstage measurements have not.

Found the review as well! 2005
http://www.soundstage.com/revequip/mbquart_vera_vs1f.htm

EDIT. I would like to state the reviewer claimed "Great-sounding loudspeakers at a very fair price."

$5000 a pair.

Did I mention the QLS are $1000 a pair.

 

[GranteedEV]

4ohm speakers are not rated @ 2w 1m.

Hold on a second. Many are, and IMO should be because speakers are not a resistive load. It might be 4 ohm somewhere, and 10 ohm elsewhere, and 2.3 ohm elsewhere.


By using efficiency, not sensitivity, that spec would be a lie, because where the impedance rises or decreases, it would imply the speaker gets louder or quieter with the same output from the amp. I'm sure you've seen an impedance graph... it doesn't stay the same, and nor do watts. voltage on the other hand does not change as a function of impedance, unless it is being limited by the amp.

Amps don't work in terms of watts, they works in terms of Volts and Amperes.

Here's a few 4 ohm and 6 ohm speakers that do use 2.83v/m like they should be doing from the start:

http://www.svsound.com/products/speakers/mts_family/MTS-02_Specs_Binder.pdf

http://www.martinlogan.com/clxart/specs.php

http://www.magnepan.com/model_MG_16

http://www.rbhsound.com/t30lse.php

http://www.revelspeakers.com/ProductDetails.aspx?prdid=2

Sensitivity can only be measured in db/v/m ... efficiency is constantly changing on the other hand and is only valid at a given frequency. 2.83 V is a somewhat arbritrary standard because it does happen to correlate to 1 w at 8 ohms but db/w/m is not a valid way of stating sensitivity.

 

[zumbo]

I love the way the Soundstage reviewer got frustrated when he couldn't use any of his "high-end" speaker cables, due to the binding post bare wire preference.

And yet such a favorable review using some cheap speaker-wire he found to work.

MB Quart/German Maestro recommends a bare wire connection on my speakers.

 

[zumbo]

.

Funny the SV you linked uses a Peerless driver.

EDIT. Make that two Peerless drivers! Each!

Did I mention that it used to be MBPeerless?

 

[zumbo]

Here's a few 4 ohm and 6 ohm speakers that do use 2.83v/m like they should be doing from the start:

I agree. But, unfortunately, mine were not.

* Impedance: 4 Ohms
* Frequency Response: 33Hz - 32kHz
* Sensitivity: (1 watt @ 3' ) 87dB

Which is why I feel they should be rated @90dB.

Correct?