New City, New System

Notes:

• Sensitivity is 94dB/W. This is a good thing, but could always be higher.
• With my current placement and room, soundstage is big. Imaging could be tighter and more pinpoint. Otherwise good space infront and behind the speakers, with the images than can appear near and far, left and right.
  
• Perhaps the best feature of the Fusion 8 is the dynamism, the ability to quickly portray contrasts in musical energy. This stands in contrast to the speakers I've built iin the past that have been probably more refined sounding but lacked the dynamic ability.
• The little bump around 5k is slightly obtrusive but not terribly grating. I'd say it manifests itself as adding a treble hardness akin to HD800. Certain recordings highlight the issue more than others.

Otherwise given the asking price (~$400 shipped w/ cabinets) I would recommend this speaker. A good entry point for those looking to match with low-power SET stuff to boot. I think they'd also work well in a HT situation as fronts given their good power handling. I have not had a chance to match with my dual subwoofers, but I imagine that system would only get better. These might eventually transition to desktop duties, assuming the larger cabinet is as well suited for listening from very short distances.

 

Can we get distortion measurements at say 90 or 95db? Wondering how well the tiny woofer deals with higher levels. Given the FR probably not that well. 94db/W efficiency in this small form factor is very impressive, though.

Otherwise, holy hell, this looks bright. Looks like I could use a good -4db high shelf after 4kHz.

 

It's a 20 cm woofer. I wouldn't exactly call it tiny.

 

Nah, all it needs is a bit of PEQ of the 5k bump

 

Contrast to the manufacturer spec:



Something else worth mentioning is that given larger spacing between each acoustic center, the response does change a fair bit when you measure on-axis with the waveguide vs the woofer. This issue becomes nulled when you move far enough away from speaker. But it's something that might prevent this from being a champ in a near-field listening situation. I normally do prefer to listen near-field, even in a big room like this.

 

To me, woofer sizes for speakers are generally as follows:

<7": Don't even bother
8": Tiny. Extended lower midrange driver.
10": Use multiple woofers for a thin speaker with high WAF.
12": Use two for good bass quality
15": Good bass quality
18": Better bass quality. Probably a good compromise between bass quality and midrange FR.
20"+: Bass.

There's no way this woofer can get less than 1% distortion at 90db+ at the listening position below 50Hz and 1% is already pretty distorted.

Are you sure it's not just that you get more room effects and essentially measure more of the off-axis FR?

Here's an overlay against the B&K target curve, but then again different speakers, rooms, listening positions, etc. all need a slightly different target. I know that with my speakers the B&K target is a bit warm, while with my dad's speakers the B&K target is a bit bright or upper mid forward. Might be that all they need is some EQ at 5kHz, but 8kHz also looks pretty bright to me.

 

No, it's the waveforms from each drive unit combining.

Like I said, I have them set up for near-field listening, so it should be no surprise that the listening position curve looks more like the near-field curve than not. And the near-field quasi-anechoic curve should look flat.

 

I thought the crossover was at 2.5kHz and pretty steep, is there really that much interference going on at 5kHz and none at 2.5kHz?

Also weird that the speaker would get a 94db sensitivity considering that the woofer only has a 94db sensitivity on an infinite baffle, but I guess it sort of makes sense since it drops off from 300Hz on. No baffle step compensation, right?

I don't give a shit about 1m quasi-anechoic measurements. Listening position is really what matters for the most part. This means voicing speakers for near-field environments warm.

 

So you get an idea, here's what it looks like pushing the LP to 3m (original was probably 1.5m). A bit more smoothing would make it look like the B&K curve

 

The bump doesn't seem to change all that much. Maybe it's just a diffraction thing? How does the off-axis response look like?

 

Take a mic and measure each drive unit and you'll see what I mean. I'm not at liberty to disclose the crossover since it is DIYsoundgroup's IP.

The bump doesn't change because it's inherent to the compression driver or maybe waveguide. What did change was the overall treble level as things are now further off-axis.

 

What is the THD audibility threshold for sub 100Hz frequencies? I don't think that distortion is a significant problem in most small listening rooms. You'll get mud from long decay times and general noise from various objects.

Oh, come on... Midrange? What kind of midrange are you looking to play from a 18"? You'll run into polar and breakup problems long before FR gets wonky. Like some other things in life, you don't describe drivers by inches alone. Motor structure, spider, cooling, suspension, enclosure geometry, etc. These all matter.

Btw, Ultra - that's a decent response you're getting. I find +/-10dB to be a bit too wide for more than a general overview.

I recently did some room simulation and repostioning thus going from this:



To this:

 

I don't know but I do know that the HD800 distortion is audible. And that's a level below my 15" woofers. (Yes, the 15" woofer distortion is also easily audible.)
Most speakers have higher bass distortion than the HD650 and there's no argument that the HD650 bass distortion is a little high.

Long decay times are a seperate problem. Yes, that's probably worse than distortion, but I don't think it helps mask distortion. Just makes the blurry mess even worse. In my room with the OBs room modes aren't such a big issue.
You might get rattle or other noise issues, but I think you can get those under control most of the time.

I think an 18" starts beaming somewhere around 750Hz, which is still pretty far into the midrange. A 21" should be around 650Hz. But yes, I mainly meant lower mids and fundamentals like you'd need for my OB woofer + widebander speaker. For this I really want the lower mids to be covered by the big woofer, because it's at such an advantage here. Bass guitars sound awesome with those bass guitar drivers.
Also with breakup you definitely get FR issues, so I don't quite get what you mean by "long before FR gets wonky". You really don't want to play a 15" or larger higher than 1kHz.

It was mostly a joke and me basically saying bigger woofers are better; there's no replacement for displacement; #MakeWoofersGreatAgain; etc, etc.

 

I agree with Serious that bigger woofers are better, but we're there is a balance to be struck. For the ultimate in bass extension a subwoofer(s) will be needed, or you just need to go for a 3-way. As far as the distortion measurements go, it's going to be relatively high. I'd run a test by my mic isn't calibrated for dBA so I'd be running off what I think 90dB sounds like. Not worth sperging out over measurements anyway. I would like to characterize the off-axis response, as that should be one of the major selling points of the waveguide design. As you guys can see, the compression driver barely gets to 20k, so forget all that ultrasonic plankton

 

not scientific, all distances are eyeballed