Wednesday, November 18, 2015

JBL Loft 40: Review, Measurements and Comparison

JBL Loft 40: Review, Measurements and Comparison

For a good part of the last year, the JBL Loft 40's have become a popular budget suggestion on due to some steep discounts from their original retail price. The product line didn't last very long and appears to have become discontinued, so once the existing stock is gone I wouldn't expect many more to be found.

I had previously done a Harman Kardon shoot out where I reviewed and compared the smaller 4 inch JBL Loft 30's and Infinity p143's, I will be doing the same with the larger 5.25 inch JBL Loft 40's and Infinity p153's.

So how do these often recommended speakers perform and stack up?

Before we get into the measurements and audio quality, let's just take a quick look at the size and build quality of the Loft 40's vs the Infinity Primus p153

Please excuse the following potato quality photos.

The Infinity p153 dwarfs the Loft 40. It's not really a fair comparison. Construction quality on the Primus line far exceeds that of the Loft. The Primus p153's are significantly larger, heavier and pass the very scientific knuckle rap test with aplomb. Where as the JBL Loft 40's are pretty light weight and ring very hollow. The Primus's are little tanks for budget speakers. 

Taking off the grills reveals a boring black box and a pretty dated looking bigger box

To be honest, neither speaker is very exciting to look at without the grills on. The Primus are especially dated looking with the two tone black and light grey. The Loft 40's are just another black box. I really hope that the Primus line gets a redesign or at least a refresh soon; they are pushing a decade old.

Measurement's and Review:
How do the JBL Loft 40's actually sound?

Here with the close mic driver measurements we can see a lot going on. It's quite a bit different than what the smaller Loft 30 does. 

Starting with the port, it has decent output to 50hz, and has relatively little port noise which is a nice bonus. 

Moving on to the midrange driver, things get a little ugly. It doesn't play very flat, there is a -10db slope across it's output. There is also a huge dip at 1.5khz that looks unrelated to any sort of null, it also have significant output to 5khz, where it drops off incredibly fast.

The tweeter on the Loft 40, seems to have a very different implementation than on the Loft 30. The Loft 30 tweeter played well enough flat without any significant peaks or valleys. While the tweeter drivers look to be the same between the Loft 30 and 40, the Loft 40 appears to cross it over much higher at about 4khz.

While I couldn't find any published documentation from JBL crossover, they both use the same layout. And while I have very limited knowledge of crossover design, they appear to have different valued parts. The Loft 30 uses a cap with a 3.3j 100v value, while the Loft 40 uses a 335j 100v value. In the end, the tweeters measure very differently. 

Some good news is that the grills are pretty transparent.

At 1 meter without any rear boundary you get usable output to about 80hz with a hump at ~150hz which matches the close mic measurements. 

It's the long and low valley from 150hz-1khz that really take away from the quality of the speaker. A vacuum of midbass and midrange that give the Loft 40 a hollow and tinny sound.

The same dip a 1.5khz as seen in the close mid measurements is seen in the 1m measurements. 

With how high the tweeter is crossed over, it's not doing all that much. I don't think the tweeter is the weak link in the speaker. As the same tweeter in the Loft 30 measures much better. The midrange driver is where the deficiencies lie with the Loft 40.

Off Axis Measurements

It isn't until you get to about 20 degrees off axis that the tweeter really loses output. You can see what looks like the peak in output at the 4khz cross over point. I guess that's better than a null, a bit easier to possibly EQ out. 

Maybe EQing out the peak and using zero toe in might yield ok results if you don't have too reflective of a room. But that's a bit of work for such a cheap speaker.

Vertical axis measurements look pretty typical, with significant nulls at +/- 15 degrees

Comparisons with the Loft 30 and Primus p153

Comparing the Loft 40 to the Loft 30 shows that they actually end up measuring pretty similarly. Voiced matched for sure. 

The Loft 40 predictably plays lower, they both share the similar midbass spikes followed by a wide valley about -5db until 1kh. The tweeter on the Loft 30 plays flatter.

With the height the speakers are during the measurement process, things should be accurate down to ~600hz, where everything after will only catch major output difference.

Comparing the Loft 40 with its Harman Kardon cousin, the Infinity Primus p153 is without a doubt the flatter playing speaker. It doesn't suffer from the valley in the midbass and lower midrange that the Loft 40 does. And it may play a little deeper if they are going to be away from a wall. However during all my desktop listening, the JBL's did seem to have the edge on bass depth, I believe due to the rear facing port and gain from the rear wall than being the better driver.

None of the Infinity Primus line are bass monsters by any stretch, since it's from ported there isn't going to be any potential gain in the lower octaves from their position relative to a wall. In my opinion the whole Primus line, regardless of your placement, should really be accompanied by a subwoofer.

The upper registers on the Primus p153 are just a touch flatter for the most part, but both speakers share a similar a similar bump after 10khz.

With the steep discounts the now discontinued JBL Loft series has become an inciting option for bargain hunters. On sale for under $50 makes these a good bit better of a deal than the were at their original retail price. 

But that doesn't mean I think these are good speakers. But they would be serviceable if you were going to try your hand at digital EQing for if you were going to use them for more limited content like rears in a surround sound. If rear fill is the case, then by all means this will probably do the job well enough.

There is just no way I could have recommend them for any type of use when they were selling for $180 to $150 a pair.  

If you really needed $50 speakers I would look into the Insignia NS-SP213 if you are also planning use a sub, it's cheap well built and easily found speaker at Best Buy, or if you can save a few extra dollars the Micca MB42-X's are a good choice. Obviously both the current offerings from Pioneer and Infinity will best the JBL Lofts also, and easily remain the two go to picks for new hobbyist depending on their musical preference.  

Friday, November 13, 2015

DIY Home Depot Desktop Speaker Stands

DIY Home Depot Desktop Speaker Stands

I needed some new sort of speaker stand to lift up my current KEF Q100's off my desk and I remember seeing these speaker stands made by Tek Everything as seen in their YouTube tutorial here.

I thought this would be a good DIY starting point, but as I can't leave anything well enough along and though there were some possible improvements to be made, so I gave them a try with a hopefully a few improvements.

Overall these are pretty easy to build, and seem to do a good job lifting the speakers closer to ear level and preventing vibrations into the desk.

I should have taken a bit more time with the construction, as there was a bit more mess from the epoxy than I had hoped.

Pictures are just a 1/2 step better than potato quality, but it should get the job done


Construction Pictures 

There were the materials I picked up at Home Depot.

4 drainage grates, 2 PVC couplings, a roll of rubberized foam padding and some DAP glue/sealant.

Eventually, I would ditch the DAP in favor of Gorilla Glue 5 minute epoxy, and I would use a heavier duty drainage gate to get some additional height and weight to the stand.

A higher number is better right?

I needed a way to seal up the drainage gates so that I could fill them with sand. The easiest solution was to use the foam mat to both seal and pad the soon to be stand.

So far it seems to be permanent solution.

Spray a bunch of the Super 90 on both the mat and the drainage grates and let them sit and get tacky for a few minutes.

I only wanted to fill them about 1/2 with sand so that I could make sure the base would be able to fully mount to the coupling.

I decided to use a bigger heavier duty grate for the base of the stands. This would let me get more sand and weight, and lift them up an extra 3/4 of an inch or so.

There was lots of tamping to get the sand to compress as much as possible.

Once the sand was about 98% full, I screwed on the grill to the grate and then poured sand on top to fill in the grated area. Once that was full and leveled off, a similar process of spraying Super 90 onto the grill/exposed sand and mat, then letting it dry and pressing it all together.

Base and foam being glued, exciting stuff!

I didn't know what to finish them in, and just about nothing sticks to PVC. So I tried Plasti-Dip.

Turned out just OK. These definitely aren't lookers but they are pretty functional. Working as fast as I did, didn't help as some of the epoxy did drip

And here they are again, complete and on the desk.

You'll see that there is also some heavy duty duct tape around the center. A few grains of sand would shake or fall out of the top portion. I don't think I used enough epoxy to seal up the coupling well enough.

I also put additional rubber pads at the 4 corners and in the dead center of the base as the base was was slightly sticking to the wood desk and didn't make for very easy re-positioning.

I think this process can yield a nice set of cheap stands and be a fun project. Just take a little more time with it than I did so you wont be so sloppy, and probably double the amount of epoxy used to ensure a air tight seal at the coupling.

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