Review: LD Systems CURV 500

Review LD Systems CURV 500Do you have a sound reinforcement or pa need? The CURV 500 system from LD systems will probably work for you because it is, above all, incredibly versatile. Stephen Dawson reports.

What is the CURV 500? Is it a PA? Is it sound reinforcement for a musician? Is it a conference room sound system? Could it go into a church? How about a large, meandering set of corridors?

The answer is, yes. To all of that.

The CURV 500 is a modular system that is equally comfortable doing sound reinforcement for an intimate performance by a singer-songwriter, or running a few dozen satellites via a 70V transformer in a large, sprawling venue. I’ll be focussing on the former function, but you can equally do the latter.

The dual nature of the system is hinted at by the wiring arrangement. Let’s start with the CURV 500 IAMP (I for installation). This is a four by 240W (into 4Ω) Class D amp. The four inputs are XLR, or terminal block. The four outputs are Speakon, or terminal block. Your musician will be using XLR and Speakon. Your installer will likely be using terminal blocks. Versatile.

It supports regular speaker impedances, but an adaptor is available to run it as a 70V system. The amp is standard rack mounting and fan cooled. It also has extensive sound processing built in, along with a front panel OLED display through which you make settings.

For a basic system you need a pair of CURV 500 satellites – white or black are available – and a pair of CURV 500 SmartLink Adapters. You can’t skip the latter. They have the Speakon input terminals and are the only way to provide the speaker signal to the satellites.

They, like each of the satellites, are slightly wedge shaped. There are two grooves atop each, with integrated terminals. A satellite slides onto the adapter. Another satellite slides atop that. And so on. The wedge shape leads to a gentle curve as up to six satellites are attached, forming an array.

Each adapter also has two holes at the bottom for mounting at two different angles on stands, or the other mounting accessories which are available, in addition to bolt holes.

Each satellite packs one 100mm midrange driver and three 25mm tweeters. This arrangement allows excellent horizontal spread of sound: 110° says LD Systems, and a vertical spread limited to 10°. They are rated at 16Ω impedance. Four stacked would come to 4Ω. Six 16Ω speakers in parallel amount to a nominal 2.66Ω.

The amp is rated down to 2.7Ω. Also provided was a 10” passive subwoofer, also able to be connected by Speakon or terminal block.



The distributor had helpfully left me ample documentation when he dropped off the system, and since I was busy on other stuff I packed it all up for a week, confident I’d be able to puzzle out how to use the system with its help. Then, when it came time, I found I’d misplaced the documentation. After the usual moment of panic I resolved to have a go anyway. I knew the satellites just clip atop each other and the SmartLink Adapter. I knew that there was a side array of DSP features in the amp. I knew that you control things using the single push and rotate front control.

And that was all I needed to know.

The system was seriously easy to setup and get going. Clip the desired number of satellites to each of the SmartLink Adapters. I had six so I put three on top of each. They slide on easily and smoothly and click positively into place. A push button on the side of each one releases the lock so they can be easily removed. I popped each stack – or array – onto the stands that had been left, extended up so the tops were about 600mm from the ceiling, and put on the forward position so they leant forward, firing slightly down into the room. The sub I put on the floor between them.

The amp was in a pro travel case, along with an LD Systems CD player that was plugged into a pair of the XLR inputs. I plugged in the ‘Speakon compatible’ cables to three of the amp’s outputs, plugging their other ends into the SmartLink Adapters and sub, and powered up the system.

It opened with a list on its OLED display showing the presets which had been chosen for the four outputs. It turned out that the sub had been set for output D rather than the output C into which I’d plugged it. I moved the plug, but I needn’t have. I could have just as easily changed the preset.

Indeed, I had to do that for the A and B satellite channels. The presets were for two satellites on each, whereas I’d put three. No instructions remember, so how hard could it be? In fact, it couldn’t be easier. I pushed the control button and was presented with a menu. I rotated the knob, moving the selection to ‘Preset’, which seemed appropriate. Pressed the knob and there were the four output channels listed again, with the (wrong) speakers shown for each. Rotate the knob and press to select a channel. Then rotate and it cycles through presets for one through six satellites attached to a SmartLink Adapter. Another for one through four using a 70V system. Plus one for the sub connection.

It took maybe 20 seconds to change all the settings.


Later I went through the other settings you can make. The EQ function is separate, of course, for each channel. The sub preset has a fair bit of EQ but the default setting for the satellites is no adjustment. Each EQ has ten parametric bands with adjustable centre frequency – any can be adjusted all the way from below 20Hz to above 20kHz, so you can have all 10 managing the sub if you want – and adjustable Q (width of effect).

You can flip polarity – most likely to be useful for the sub if the relative positions of the speakers lead to a notable suck-out around crossover. You can apply a delay to individual channels. This is calibrated to both milliseconds and distance in feet or metres.

Want precision? In the master settings you can set the temperature to be used for the delay. Temperature? For sure. The speed of sound, and thus the necessary delay for a particular distance, varies according to temperature. Not by much. At 20°C it’s 343.5m/s. At 30°C it’s 349.3m/s. Litt le practice difference if this were a home theatre system, but you can dial in up to 57m of delay so those milliseconds can add up. If you want to delay the rear house speakers, you ought to be able to get things right here.

Of course the level of each channel can be set individually. The subwoofer level was way too high when I first set up the system. On digging into the menu system I found that it was already set to -12 (dB) while the main speakers were on zero. Had this been a consumer system, there would have been no room for further adjustment.

But it isn’t. You can set any channel to between +6dB and -60dB. Or you can mute a channel. I decided on -18dB.

Finally, routing. Any of the four inputs can be mapped to any of the four outputs.

All four in to all four out if you like, or any combination thereof. As supplied, inputs one and three were mapped to output A (call this left channel), two and four to B (right channel), nothing to C and all four inputs to D (for the sub).

Note: this is a router, not really a ‘mixer’ because there is no built in input level control.

So I plugged my own (very modest) mixing panel in inputs three and four, and that allowed me to use a microphone and play non-CD sources.

Character of sound? There’s really not all that much to say about it for two reasons. First, because it was very neutral even with the default zeroed-out EQ setting. Second, because of you don’t like it you can EQ it to something you prefer.

I liked it. A great deal. The system does seem to be a development, a step up, from systems liked by musicians and it has preserved that heritage. For the audiophiles out there, the stereo imaging was very good, if different. The difference was due of course to the main speakers being raised so high, not in the usual hi-fi speaker position. But, of course, in many sound reinforcement and just about all installation situations, any stereo channels will be routed to both speakers.


The other important point is capacity. How loud can it go? I went to Led Zeppelin to find the answer. Ripped audio from the How The West Was Won DVD Audio disc, played loud. It went loud, but initially sounded horrible. It took me a moment, but I discovered I was driving my own mixer into clipping. I backed that off and turned up the CURV 500 system, and up it went, clean and powerful, with excellent impact and a tight, controlled and powerful bass that matched what the satellites were doing.

The sound was peaking a little above 110dB SPL (C-weighted). Aft er running this way for half an hour, the amp had barely warmed.

How about a more basic system? I zeroed out the volume control, slid off the top two satellites from each side, change the presets from three to one satellite each and turned the volume up again. Time taken? One minute.

Then I backed off the subwoofer by 6dB to bring it back into balance and changed the channel routing to mix the input down to mono. Playing some Laura Marling, the results were simply marvellous. Any vocalist would be pleased indeed with this system for any reasonably sized venue.


The CURV 500 system is fine sounding, reasonably priced and extremely versatile.


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