DR290 review with eq/delay/phase settings (so far...)

[DAVID_L_PERRY]

Full review can be found here:-
http://myweb.tiscali.co.uk/prosoundhire ... review.htm

I have completed and been using a pair of the DR290’s for approximately three months (as of Jan 2007) for live band Pa use and during this time taking the time to evaluate the speakers output to the best of my ability.

Each cab is loaded with a 12” Eminence 2512 driver and a pair of 1” JBL 2416 HF drivers
The cabs are bi-amped with the 12” drivers powered off one side of a DAP Vision 2400 (600w per driver) and the horns powered off a Soundtech PS802 stereo running at 16ohms per side (approx 180w per side)

System crossover settings:-
Subs / mids 80hz (24db slope)
Mids / highs 1.2khz (24db slope)
http://myweb.tiscali.co.uk/prosoundhire ... ttings.jpg

A brief history before the completed speakers where put to work:-
I was drawn into this design as it utilised only a single 12” mid/bass driver and two 1” HF drivers and was in a fairly compact box (considering its output). A big consideration for myself was that the box size matched exactly my existing modular subs so stacking and packing in the van would be made simple. I did not want to change my system to a 4 way system, and most other high output top boxes where much bigger (generally front loaded 2x12 or 2x15).

Most of my gigs are Large Bars, small clubs largest gigs currently about 500 people. I was pretty dubious about the claimed output of the box following discussions on other Speaker related web site forums, however I decided to take a gamble and try out the design. As the build of the box is pretty time consuming and fairly complex, I decided to build just one DR290 so I could listen to the end product before committing to building the second.

Trials of the first DR290 speaker comprised of simple listening tests up against my existing sealed baffle loaded tops, and two other respected separate mid/top cabs.

I encountered several problems during the initial tests, all eventually overcome. These where mainly down to not utilising the specified Eminence driver (It was not available in the UK at the time of construction) Most importantly I think was that the polarity/phase issue of the 12” mid range driver was incorrect, causing a massive dropout at the low crossover. The details of the initial tests can be found here:-
http://myweb.tiscali.co.uk/prosoundhire/dr290.htm

EQ setting and delay/phase setup

I spent a lot of time with the cabs in order to setup the delay, eq and attempt to sort out the phase settings of the drivers. I have normally only used an RTA (real time analyser) and pink noise for this, however I downloaded the 30day trail version of Smaart to try and assist in setting up the system to the best of my ability. This bit of software in its simplest form can be used for RTA analysis, however it also can be used as an aid in setting up the correct time/phase setting for the speakers amongst other things. Having had no formal training on this software and only using it for a matter of a week I will not include the results as I can not be relied upon to have carried out or interpreted the test results accurately. I was at least happy to obtain a good coherence trace and fairly flat RTA plot.

As the 12” mid/bass driver is mounted on a long folded/bent horn, the HF driver requires time delaying. I utilised my Behringer Ultradrive digital speaker management and measurement microphone to establish the delay path time and this came out at approximately 1.1m delay for the HF section (which corresponds to the horn path length). The ultradrive also swapped the polarity of the 12” driver and HF drivers during the setup procedure. Unless the 12” driver had its polarity inverted, there was a noticeable loss of SPL at the low crossover between the mids & subs. This drop could be seen on the RTA plot and also was clearly audible.

http://myweb.tiscali.co.uk/prosoundhire ... etting.jpg (Delay settings for HF 1" horns)

I experimented by restoring the polarity and adjusting the phase of the 12” driver. I utilised the coherence curve of the Smaart display and RTA displays as a visible aid whilst adjusting the phase settings of the 12” driver and found that the smoothest response came about with the phase at 145deg. This was also an audible increase as well as visual increase at the crossover freq. Howevor the resultant phase plot on Smaart looked like the peaks of the Himalayas !! I am currently trying to make more sense of this phase arrangement, however, regardless of the displayed phase plot, the sound is there…
Phase
http://myweb.tiscali.co.uk/prosoundhire ... etting.jpg (phase settings for 12" mid bass driver)

http://myweb.tiscali.co.uk/prosoundhire ... etting.jpg (phase settings for HF 1" horns)


EQ settings
In my view EQ is absolutely imperative to get these cabs to sound good….with detailed work on the EQ these cabs sound superb…

These are the eq settings so far to obtain a fairly flat response as checked using both Smaart and my RTA display:-

(overall eq settings)
http://myweb.tiscali.co.uk/prosoundhire ... l%20eq.jpg

(Close up eq settings)
http://myweb.tiscali.co.uk/prosoundhire/dr290eq1.jpg
http://myweb.tiscali.co.uk/prosoundhire/dr290eq2.jpg

During the first 4 gigs I found a low constant resonance spike at about 125hz on my vocal mics that kept ringing, and had to be carefully notched out or too much low end was lost. It took a while to isolate this odd sounding low end resonance (found with my SM58’s and Audix OM7 vocal mics)

Forget the tests, how did they sound…..
I supplied the PA for a 400 capacity rock gig with plenty of headroom left. It was a loud gig, and a fairly large hall. Centre clustered subs, tops raised up on the stage area just above head height.

Centre cluster
http://myweb.tiscali.co.uk/prosoundhire ... 20subs.jpg

I tried the tops turned on there side so the HF drivers are horizontal (as per the DR300 stand alone use), but the tops high freq sounded better when flipped vertical as they should be. The DR290's have an optional HF diffuser to increase the Horizontal spread to 90deg, but I did not have this fitted at the time so I had approx 60deg as standard. When I walked the room during the gig I was still very happy with spread although, it was a large room so close up smaller venues would tell a different tale.

Having fitted the vertical slot diffusers to the HF horns, and having had a chance to use the tops at familiar smaller venues, the top end horizontal dispersion is far superior than I have had before. With some eq above 10k I have now gained the top end ‘sizzle’ I was looking for.

DR290 Stacked with subs
http://myweb.tiscali.co.uk/prosoundhire ... 20side.jpg
http://myweb.tiscali.co.uk/prosoundhire ... 0front.jpg


Conclusions
My personal view so far is that the DR290's have given me the best sounding live band mix I have had to date. What that means to me is that I have clearer vocals, more powerful drums, and guitars, than my previous baffle loaded mid tops could produce. The additional lower mids are fantastic. It is quite apparent that I have always been missing these lower mids in the mix, but only since running the DR290 have I actually known it. When doing line level checks with the bands, I initially didn’t think the vocal output was particularly high, however as soon as the band kicked in I realised I was just hearing loud clear lead vocals. For the first time in years I was dropping the vocal sliders when the vocals came in ! Boosting guitar solos takes less adjustment on the channel strip as the cabs are far more efficient than my previous tops. The bass guitar was far more detailed and punchy. The drums have far more impact throughout the Kick and toms. High hats and ride are also more detailed (I assume down to the 1” drivers being better at the top end than my previous 2” HF driver).

I enjoy the actual process of speaker cab building, and as such the cost of building the cabs for me is well worth it. I would strongly suggest that anybody who is going to build or pay somebody to build a set of these tops gets the chance to listen to them first if at all possible – again, without the required corrective EQ the cabs do not have a chance to really shine, and may cause major disappointment at first listening.

The Fitzmaurice forum is a superb source of information and a good chance to ask many other builders of any pitfalls you may encounter.

Hope this is of some use and interest

Dave Perry

[Bill Fitzmaurice]

This review also appears in the DR forum, so any replies may be posted there.