New Equipment!

April 13, 2018

As mentioned in the March 2018 blog post, here's where I'll discuss the new equipment we have in store at Grimshaw Audio.

 

First up, a pair of small PA speakers:

These are 6.5" two-way cabinets, with the following features:

 

- Top-of-the-line components - the 6.5" midbass is a top-end unit from 18Sound, the 6ND430. This driver features a neodymium magnet with an integrated heatsink for exceptional power handling, and a large amount of linear cone travel which means these small cabinets are impressively loud. The high-frequency unit is an older model, the DAS M3, which was recycled from the first set of PA speakers I owned. While it's an older unit, it's still fantastic - while fairly small, it will run happily down to 1kHz, which is almost unheard of for a small-format compression driver. It's also very smooth and clean all the way up into the highest treble regions.

- Asymmetrical high-frequency horn coverage. The high-frequency horn used here features a coverage angle that is wide when you're below the speaker, and becomes more narrow as you move upwards. This is a great compromise as the sound is spread widely when you're up close to the speakers, so the people right at the front still hear everything, but the sound is also "thrown" well to the back, without becoming muddied by reflecting off walls.

- Passive crossover for ease-of-use. Where the large main speakers use an active crossover and seperate amplifiers for the ultimate control, these new speakers run on a single amplifier channel. Implementing a top-quality passive crossover can be difficult, but the flexibility of the high-frequency unit meant excellent results can still be achieved. Here, the crossover frequency comes in at 1.6kHz. That's lower than competing products, but taking the crossover much high results in the 6.5" driver "beaming" through the kHz region, where the dispersion gets very narrow. The result is a loss of intelligibility for the people off to the sides. These speakers avoid that, and provide an even sound for the entire audience.

- 250w continous (500w peak) power handling. Using an amplifier capable of 500w per speaker, these cabinets have plenty of output for small venues.

- Impressive low-frequency extension from a small cabinet. These cabinets are flat down to around 60Hz, which what most 15" cabinets manage. While the 15"s may get quite a lot louder, when you want a full-range sound from some very small PA speakers, these are the ones to reach for.

- Careful acoustic treatment of all internal surfaces has meant the sound of these speakers is exceptionally clean. There's a lot of talk in the HiFi world of speaker cabinets sounding "boxy". The first prototype of these speakers had that problem, and the cause was midrange sound escaping from the bass port - the delayed effect was causing all sorts of problems with the sound. While blocking the port did help, it also cut off all the bass that these speakers are capable of. Through careful positioning of absorbing materials inside the cabinet, as well as treating every internal surface, the "boxy" sound was eliminated completely, just leaving the exceptionally pure sound from the top-end drivers in play.

 

While these little speakers are excellent on their own, I'm working on a set of companion subwoofers which will be a very low-profile design (around 8" tall), and each subwoofer will form a base that the new speakers can then be mounted to, using a distance pole to get the appropriate height.

The subwoofers will take over the low-frequency reinforcement from the main speakers, increasing headroom hugely and allowing a very compact set of speakers to cover some fairly large spaces.

 

 

Next up, we have some new microphones. In celebration of 20 years of Sennheiser's Evolution line of mics, they've been putting a different mic on a 50%-off sale each month. In February, it was the e904.

Naturally, I had to try one, and picked one up online at the discounted price.

The next day, I took it to the Open Mic Night at the Red Deer in Sheffield, where I often run the sound. As a result, I got to try the e904 on a few different acoustic instruments in quick succession, and recorded the results using the digital desk to review later.

The results were very positive, so I set up the microphone measuring system to verify Sennheiser's graphs. The two measurements (theirs and mine) are exceptionally similar, and both show the same thing - the e904 has an exceptionally smooth and flat frequency response. It makes the likes of a Shure Beta-57a or SM57 sound very coloured indeed.

After that, and some more sound tests, a more substantial order went in, and arrived shortly afterwards:

 

 

Armed with a bag full of the new mics, I took them to a rock gig to give them all a good work-out.

They saw use on the drums, of course, but also micing the bass amp, guitar amp, and anything else that needed it.

The results were excellent across the board. I tried the e904 next to the usual kick mic (with the e904 being recorded, not sent to the main PA) and found that the only thing it lacked was a little low-frequency extension. Where the usual mic produced a very "deep" sound, the e904 lacked some of the very bottom frequencies, giving a sound that was more "punchy". Both kick sounds were perfectly acceptable, though.

The guitar amp and snare/toms all sounded great straight away. There wasn't any need for processing - with the e904 mics, the sound you get is exactly what the instrument sounds like - they're incredibly natural, which means you don't need to alter the signal much to get great sound.

The standout, however, was using an e904 as the drum overhead. This was quite unexpected - most engineers will insist on a condenser mic to capture the cymbals etc, but the e904 did just as well - once properly positioned, it captured an excellent overview of the drum kit. Indeed, with a bit of the kick mic blended in, the sound was more than just "usable" - it sounded really good, and a two-mic setup like that will certainly be in my mind for quieter gigs.

 

That's all for now - I'm going to get some more work done on the new low-profile subwoofers.

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