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Following on from this post in the what are you building thread I thought I'd make a new thread as its gone on for a few posts. I did some "directivity" type plots of both the LTH142 horn and PH916 waveguide outdoors, using the lazy susan. Although my garden is pretty small it still is more open than my loungeroom. These were done at 2M distance, with no crossover except the 66uf protection capacitor, and smoothed to 12/octave for readability. Each reading is done rotated 7.5 degrees off axis, so I've got from 0 degrees (direct on axis) to 60 degrees available: Now I'm using a miniDSP EQ correction that makes the PH916 fairly flat on axis.. and I forgot to change this for the LTH142 when I switched over to this, which measures louder in the high frequencies. But it appears the PH916 has mostly better directivity as the FR falls off slower (narrower spread of lines), except it has more chaotic behaviour (notches appearing) above 12khz, while for the LTH142 although it has a notch on axis.. it actually gets smoother off axis at these high frequencies. I'm now toeing in my speakers @ 22.5 degrees to the listening position (and have adjusted the miniDSP EQ to suit), but as Paul mentioned getting the measurements across different angles has opened my eyes a bit. I'm still preferring the PH916, though it looks to me like for a more beamy response the LTH142 will actually give me more even high end frequency response. I'm currently set up crossing over at 700hz with a somewhat complicated MiniDSP EQ curve flattening out the response from the 800-3000 region. Still learning as I go here, but it's sounding pretty good.

Hi, I thought I'd post an overview of my loungeroom system now its approaching completeness in it's current form. Portions of this have been documented in the DIY section here and other sites and forums, but here it is as a whole system. The overall plan for this system has been a simple active two way with horn/waveguide HF section, taking on board ideas from both the "Econowave" project and a nod towards those older big American speakers with horns & 15" bass drivers, like Klipsch, Altec, etc. But using a modern active DSP crossover, and mostly digital sources. I've also just been switching amps and other parts in and out for fun, buying random DIY boards from the internet if I read an interesting thread, etc. I tried two other waveguides before settling on the current one. It's not particularly high end, there are a few rough edges I need to refine, but it is probably unique and I like the sound. HF section. 1.4" compression driver and waveguide, FaitalPro HF144 with 18Sound XT1464. I've got this just sitting on the woofer enclosure, for ease of trying different waveguides. The compression driver is propped on a small wooden box that holds the LPAD resistors (7dB attenuation on the HF) and protection capacitor. JLH 1969 8watt Class A stereo amplifer. These are usually 10W but I am running it at a lower voltage. This is a very simple build from a Chinese kit, using a switched mode power supply, and the enclosure is re-cycled from an old Korean amp. This is the "winter" amp, during summer I was most recently using a $6 15W TDA7297 chipamp. Crossover frequency is currently 600Hz (or was it 550?). LF Section. 15" LorantzC390X B1 Australian made bass drivers. I was checking out all sorts of US, UK, Italian and Spanish drivers.. but ended up with one made in Dandenong. These are in 140 litre pine plywood bass reflex enclosures. Drivers second hand from ebay. ConnexElectronics TA3020 V3c "Tripath" Class T amp module. In a very industrial steel PSU case as enclosure, powered with a 500VA 35v-0-35v transformer, the highest voltage this can run at without needing a cooling fan. Approximately 110W/channel. I've attached a bit of stained pine to the front to cover most of the industrial steel ugliness. Crossover & Sources. MiniDSP 2x4 crossover plus miniDIGI daughterboard, with OPA2134 opamps on the output as the miniDSP is too quiet to drive most of the amplifiers I try. This is all mounted in a rough and ready pine enclosure, with a "fine" (miniDSP software) volume control and a "master" (ganged stepped attenuator for the opamp stage) volume control. There is an analogue "guest" input on the front panel for visitors to plug in their DJ mixers/laptops/etc into, but the main sources are all optical SP/DIF. Powered by a Jaycar kit linear power supply. Input selection: optical sources selected with a mechanical optical 4 way switch, an AC-1597 from Jaycar. Main source: a "home theatre" PC running Xubuntu Linux 14.04, with an Intel i3-2100t CPU on an Intel motherboard, Antec ISK-300 case, and an SSD. The problematic Antec PSU replaced with a PicoPSU. I mostly play .flac files streamed via NFS using the Linux "clementine" media player app. Youtube and Mplayer get a lot of use as well. The audio is just using the stock optical out on the Intel motherboard. This PC is about 4 years old but works just fine, and runs extremely quiet despite it's two fans. TV - Sony Bravia KDL40 EX500 40" LCD TV. This mostly gets used as a monitor for the PC, but the optical out is hooked up for the rare TV session. DVD/CD player. An old DSE "Digitor" DVD player. Definitely not a high grade unit, not often used but it does appear to handle a lot of formats so kept around. Other bits. Interconnects are mostly DIY from Altronics and Jaycar parts. Wireless keyboard and mouse. Speaker cables and optical cables from Selby Acoustic. ALDI master/slave powerboard - this is very handy, it uses the TV as a master device and turns off the amps & miniDSP when the TV goes into full standby mode, about 15 minutes after the TV is turned off with the remote. Not such a big deal with the miniDSP and Class T amp, but great once Class A amplification was added to the mix. So the whole system (except the PC) can be powered on/off from the TV remote. I've intentionally assembled all gear with no panel lights to cause distractions, the lights on lots of gear were annoying my wife. Things still to do: I still have a lot of work to do refining the crossover, I've done some initial work with The Active Crossover Designer with good results, but I really need to dig much deeper here. I've had a lot of help and advice from the guys in the SNA DIY section, thanks! I'm not completely happy with the finish on the speaker enclosures. The third coat of stain/varnish was applied at night and I didn't see the drips and patchy bits. One day I'll haul them out for another sand and coat. But its OK. The digital source is pretty much "out of the box" Linux with Pulseaudio. Apart from verifying I'm getting unmodified 16bit/44100 for CD quality flac files, I haven't explored too far here. The miniDIGI does on the fly samplerate conversion and reclocking to 48khz so maybe it doesn't matter.

Hi all, I'm considering plans for a new DIY project that's a variation on the portable boombox concept, hopefully with a more linear frequency response due to higher quality drivers and equalisation and (possibly) digital crossover using MiniDSP. The other major difference would be that the system would be modular, i.e. each driver would be housed in its own box, as would the mimiDSP/battery/PS/amp, and all would slot and fix together making them usable as either a portable boombox, or, at home, a 3 component (2 x speakers + 1 x amp/crossover/psu) system. It won't be dirt cheap, but I do want to keep costs down and try to achieve similar sound quality to a similarly priced consumer hifi system, so around 300-350€ (I'm in Germany these days, hence the Euro) or a bit more if I go for a more complex design. Similar projects have been written up extensively online as 'DIY boomboxes', but the main differences I'm considering in my build are: - the addition of a MiniDSP chip (or two) to improve the frequency response and (possibly) to replace the passive crossover with an active crossover - the use of modular boxes, allowing the system to be utilised as separate components I've chosen the PC165F because they are coaxial (making them easy to deal with) and relatively sensitive (91.9db @ 2.83V/1m), yet (according to Focal at least) have a reasonably linear frequency response and decent dispersion characteristics, as well as sufficient bass extension. On the other hand, I'm concerned about the high resonant frequency (70hz) and the high magnitude of the resonance peak (over 50 Ohm), especially given this will be powered off a cheap battery. So at this stage I'm also open to other driver suggestions. Input will be stereo RCA (or 3.5mm jack) into MiniDSP. From there, I am considering the following options: (1) MiniDSP as EQ (only) / 12V lead acid battery The MiniDSP would be used simply to create a high pass (maybe 40hz) filter, compensate for baffle step, and iron out frequency response problems in the mid and (particularly) high range. I would house the coaxial drivers in well constructed 10-15 litre MDF boxes, and use either sealed boxes or more likely ported boxes, tuned (hopefully) to around 50hz. The MiniDSP would provide a quite steep high pass filter at 40hz-ish, and some EQ to compensate for baffle step and iron out irregularities in the response. This is the concept in a microsoft paint drawing: The basic equipment I have in mind for this is as follows: 1 x MiniDSP 2 x Focal PC165F 1 x Hifimediy T1-M TK2050 1 x 12V UPS lead acid battery 1 x switching PSU With this configuration, I have these questions: Power Is it a good idea to use a 12V UPS lead acid battery for something like this? The basic reason I have it in mind is that it's cheap (around 10-15€) and easily replaceable. Are there better ideas for the battery? If I do use such a battery, how do I set up the system to: (1) run off the PSU when plugged in and switched on, (2) charge the battery when plugged in and switched off, and (3) run off the battery when unplugged? I'm an electronics novice but a patient learner. Is this something I can realistically and safely achieve? Is there a simpler way of doing this that I'm missing? For example, is there a ready-made battery/psu that I could choose that would recharge and provide power to the system at the same time, so that I don't need the PSU or any kind of switch? The miniDSP also needs to draw a small amount of power from somewhere. Where would this come from and how would I make it work? Speakers These drivers have slightly odd parameters as I mentioned before: Will that very high magnitude resonance peak be a problem for a relatively low powered amp like the Hifimediy T1-M running off a 12V battery? The amp is 57w into 4Ohm with a 24V DC supply, but where the resonance peak is it would be running off a 12V DC supply into probably at least 40 Ohm (I am assuming that the heavily damped ported box will move the resonance up a bit from 70hz and reduce its magnitude somewhat). My understanding of how this amp works is that it might struggle to produce much power in this frequency region, is that right? Boxes The driver parameters suggest a ported box will work better, and since these are going to be midwoofers, ports would make sense from the point of view of efficiency. Can anyone see a problem with using a 10-15L box with damping material, with a 5cm diameter port tuned to quite a bit below the Fs (hopefully 50hz), and a digital high pass filter just below the port tuning frequency? (2) Extra amp and sub This would involve adding an additional monoblock chip amp and a small high-efficiency sub, which would most likely be housed in the central unit with the battery and amps etc. This would change my power supply needs, but I'm not sure I understand how. Assuming I found an efficient D-class monoblack 50w or 100w change amp, how would I calculate my power requirements? Would there be any chance of sticking with the 12V lead acid battery or would I simply need to abandon this idea? And does anyone have any suggestions for a decent, small (ideally 8 inch) and efficient subwoofer and amp for this arrangement? (3) MiniDSP as crossover This design idea would be very similar to (1), but in this case the miniDSP would split the input between the woofers and tweeters and replace the passive crossover in the driver unit. There would be an additional Hifimediy T1M amp giving a total of 4 channels. My question here would again be about the battery and PSU. If I were now powering two Hifimediy T1-M's off one PSU or battery, how would that change my power requirements? Would I need a more powerful battery? If so, how powerful would it need to be, and does anyone have any idea what I might use? (4) Extra amp and sub / 2 x MiniDSP This would be the most complex setup and would involve housing an additional sub in the central unit, adding a MiniDSP to create a 2.1-way crossover, and adding an additional sub amp. My question about power supply / battery is similar to my question about the extra amp in design (2) and (3). How would I calculate my power requirements? Are there any suggestions for batteries / PSUs? (5) 2 x sub / 2 x MiniDSP This is basically like design (3), but there are 2 subs instead of one and an additional stereo amp (rather than a mono amp) to power them. The subs would either both sit in the central unit or would have their own boxes, ideally also not much bigger than 10-15L in size. I guess my questions about this design are basically the same as for design (3). Many thanks in advance.

Hi all, There are endless forums on miniDSP products and as such I'm hoping to save a few hours reading. I am thinking about integrating my SVS SB13 Ultra into my 2 channel set up and if I do i was considering giving my amp and speakers an easier time by filtering lower frequencies. All I want is to put a xover between my DAC and integrated (not interested in doing room correction with miniDSP. I am considering room correction with either acourate > HQplayer > microrendu/ SOtM) So either the 2x4 or 2x4HD is what I am looking at but open to other considerations being models or other brands/solutions. The sub has a lot of DSP processing too so I don't need miniDSP to handle any of that. My question is.... is adding this going to be detrimental to sound quality by the introduction of noise or anything else audible that will outweigh the gains of the amp and speakers having an easier time? Are there other solutions or crossover devices I could use instead of miniDSP? Maybe Behringer? I know there is DEQX but it is a bit of overkill if I am happy with my pre, DAC and streaming. Any help would be greatly appreciated Dan

Lucie Audio 8pm Wednesday 18th July, visitors welcome. Willis Room, City of Whitehorse Offices Maroondah Highway (Whitehorse Road), Nunawading Melway Map 48 Ref G9 Contact: 9437 1249 When it comes to choosing or designing a loudspeaker there are two rules to consider: Rule #1; There is no such thing as a perfect loudspeaker. Every design is a series of compromises. Rule #2; One has to accept that there will be compromises and decide on a design which reduces these compromises. This month's presenter has developed a speaker system which further reduces the compromises associated with the conventional passive loudspeaker. Rick Bond from Lucie Audio will be demonstrating his speaker system which utilises active crossovers with room equalisation by means of his DSP pre-amplifier. "Our pre-amp is built around the capabilities and feature set of the MiniDSP 2x4HD processor board. This gives us the power to process the stereo audio stream in real time to perform room corrections and digital crossover functions. Correction technology is powered by Dirac Research AB, world leaders in this field". The process maps out the frequency and impulse response characteristics of the speakers in the room in a 3D grid around the listening position. After completing a frequency sweep with a microphone connected to the computer, a desired frequency response curve and an optimised impulse response are measured; the data and a set of filters are generated to map the two together. This data is then uploaded to the unit and stored in one of four configuration slots. This provides great flexibility in that up to four combinations of tonal response, crossover parameters and optimal listening position can be stored and readily recalled via the unit's remote control. "To get the best from the MiniDSP hardware, we developed an active analogue volume control board. Maintaining volume control in the analogue domain provides the best approach to the gain structure". Rick will be demonstrating his system with two sets of book shelf speakers and a matching subwoofer. He has developed these two distinct speakers to cater for the tastes of the listener. The Lucie Model One Loudspeaker is a 6.5" Point Source design. The full range driver is sourced from Dayton Audio for its zero crossover distortion. Excelling at delivering the nuances in the midrange, this design is recommended where primarily acoustic music is appreciated in a small to medium, focused listening environment. The Lucie Model Two Loudspeaker is a traditional two-way compact speaker with drivers from SB Acoustics and Scan-Speak. Recommended and pre-set crossover slopes from the DSP Pre-Amp are set at 6db per octave and centred at a fairly high 4kHz. First-order crossover slopes are chosen for their phase neutrality, made possible by the smooth and extended response of both drivers. This bass reflex (ported) design has a greater power handling and more driver excursion, better suited to bass-heavy music. The system extends the response well below the frequency of the cabinet, giving exceptional performance for a fairly compact enclosure. Cabinet materials are chosen for their high density and sustainability. Narrow grain carbonised Bamboo or Baltic Birch ply are laminated, no veneers are used, precision CNC cut then hand assembled and finished. Due to the laminar sheet construction inner wall profiles are able to be uniquely contoured to minimise internal reflections and cabinet resonances. This will be Rick Bonds first public presentation at an audio event. A relative new-comer to the HiFi scene, this young man has developed a complete active system that puts DSP technology within the reach of many audiophiles. Nick Karayanis Program Co-ordinator Ken Tripp Wise and Wonderful Webmaster Melbourne Audio Club, Inc. http://www.melbourneaudioclub.org.au

New Landed cost $700+GST if you buy together from Hong Kong, more if you buy separately. Postage will depend on where the buyer is. The Dirac Live licence is easily transferred by the buyer with the serial number of the DDRC-24. Process outlined on minidsp website. https://support.minidsp.com/support/solutions/articles/47000681565-i-purchased-a-used-ddrc-24-ddrc-22-shd-nanoavr-dl-ddrc-88a-how-do-i-get-the-software-transfer-the- The UMIK-1 has a serial number which allows the buyer to download the calibration file. from minidsp.

Further information: Up for sale is MiniDSP UMIK-1 Calibrated MIC in near new excellent condition. This was purchased directly from minidsp.com along with miniDSP 2x4 HD (sold) unit. Calibration files can be downloaded from minidsp.com by supplying the serial number of the mic. Comes with original box and package contents. Selling this unit along with few other gears to fund Power amplifier for HT use. I can ship this item at buyer's expense or local pickup can be organised from Oran Park, NSW 2570. Photos:

Item: Minidsp DDRC-24 ((with latest DiracLive 2 series, the latest upgrade) and minidsp umik-1 (usb mike) as new with packaging Location: South East Suburbs , Melbourne Price: $530 ( New Landed cost $770 if you buy together from Hong Kong, more if you buy separately). Can post for about $30 because there are two boxes. Item Condition: As new, 4 months old Reason for selling: No longer needed ( changing my setup to simplify and consolidate gear) Payment Method: Pickup - Cash, Bank deposit Extra Info: The Dirac Live licence is easily transferred by the buyer once the serial number of the DDRC-24. Process outlined here on minidsp website. The UMIK-1 has a serial number which allows the buyer to download the calibration file. from minidsp. This is all you need other than 3-4 m USB mini cables and a mike stand to easily mount the mike at listening height( I have both of these, if you pick I can sell for $35 extra all up) Photos: Advertisements without photos of the actual item will not be approved.

Further information: Bought new from miniDSP September 2016. It has been an integral part of my system until recently and provides a serious upgrade for the money. Highly recommended. It has been upgraded to Dirac 2.0 and includes the supplied remote. Also included is a bound set of printed instructions. I now use Roon convolution instead which reduced the box count. Please note: The price does not include the calibrated Umik-1 microphone. These are easily available but happy to talk about it. You will have to change over the licence but that is apparently quite straight forward. miniDSP advise changeover can take a couple of working days. Photos: Advertisements without photos of the actual item will not be approved.

Further information: miniDSP 2x4 HD for sale. This is a really great little unit to fix and correct subwoofer frequencies, it can also be used to integrate up to 4 Subwoofers from 1 or 2 inputs. Also can be used to flatten the frequency response of your stereo speakers. Possibilities are endless. It is nearly in new condition and comes with IR Remote and original packaging. This unit nearly cost me $375 AUD when I purchased it from miniDSP directly late last year. Selling as I need the funds in current times. Pick up from Oran Park NSW 2570, I can ship this item. Photos: Advertisements without photos of the actual item will not be approved.

Item: See below Location: South Sydney 2226 Price: See below Item Condition: New like Reason for selling: Analogue dreams Payment Method: Pickup - Cash, Paypal, COD Only Extra Info: Gustard U12 USB / SPDIF XMOS convertor 32 bit 384k (New in opened box) $180 posted Open DRC DA8 - DAC, room correction and 4 way electronic crossover and by Minidsp (New like, had a fiddle but has not been set up - with original box) $SOLD (will cost you $460 delivered from minidsp) Photos from web: OpenDRC DA8 Gustard U12:

Item: MiniDSP 2x4 HD Price Range: Negotiable Item Condition: New or Used Extra Info: Please don't forget to report your post as FOUND when possible. (You can now delete this text).

Looking for something with room correction, please send offers via PM. I've had and tried many, but have a number of new subs from JBL and am looking for both crossover and room correction..

Further Information: I have a Minidsp Flex and Umik-1 microphone combo in great condition for sale. Purchased from minidsp in Febuary 2022 but rarely used. No dirac room correction licence included. https://www.minidsp.com/products/minidsp-in-a-box/flex . Can pick up or deliver in Melbourne West. $740