DIY 12 INCH 3 WAYS 12.5.1

POST 1 
GETTING STARTED 
DIY active speaker 3 way grizzlyaudio DSP

This is the first blog post covering the fabrication of my DIY SB Acoustic | Seas 3 way speaker. The 3 way, is a custom designed speaker which incorporates a SB Acoustic 12inch LF, Seas 5inch MF and SB Acoustic 1 inch dome HF driver set.... Code name 12.5.1  

My goal is to post a series of entries closely detailing the design and build of this speaker... 


I have decided to post my DIY design here, to aid other DIYers considering a similar build. Why? because during my research there was NOT alot of large format "HiFi" driver based designs and builds around to reference. Sure Zaph Audio and Troels Gravesen provide some very nice designs, but none really tickled my fancy, for whatever reason - I.e. driver cost, enclosure size, difficulty, etc. I also eventually decided not to travel the pro driver high efficiency route - for better or worse..


ALOT!!!!! of goggling, discussion and modelling has been undertaken before final selection of drivers and cabinet design was selected. As a result the 12.5.1 3way speaker design is the product of many 100's+ of hours of research and consideration. In fact over the past 6 months, I have modelled many, (30/40) drivers for my application, including both lower and higher efficiency driver designs. 


If anything this design phase "backed up by computer based modelling" has reinforced my decision to go with the 12.5.1 design. I believe it offers a fantastic mix of driver efficiency, cabinet aesthetics/size, cost outlay, driver quality and modelled frequency response. 


At the end of the day the 12.5.1, (if modelling is correct) will yield a 90db @ 8ohms / 1w/1m speaker system....which with room gain, is estimated to deliver a circa flat response from 25hz - 20khz. This estimate is based on "actual" measured room gain data via a miniDSP UMIK-1 and REW (free measurement software). My listening space yields room gain of circa +6db at 30hz, and +6-8db at 25 and below. Please review the transfer function plot below for the SB Acoustic SB34NRXLl75-8 modelled transfer/response curve. 


My goal is the 12.5.1 will hold its own against $10,000+ commercially designed & sold speakers...... Additionally when one has as much difficulty as me finding a commercially available audiophile HiFi speaker with large format woofer/bass drivers (for any sane amount of money), the significant investment in time required to produce/build and design this speaker begins to make perfect sense for any DIY audiophile trying to achieve audio nirvana. 


DESIGN GOALS 

My design goals are simple, construct a "cost effective" passive/active monitor style speaker system which offers superior levels of: 

  • Transparency 
  • Sensitivity 
  • Full range performance  
  • Dynamics 
  • Power Handling 
  • Musicality 
So lets look at the driver selection.

SELECTED DRIVERS


Driver Selection Parameters:

  • Actual efficiency in the 90's at 1w/1m (2.83v @ 8ohms) = 90dm 1w/1m  CHECK 
  • Drivers must be efficient and high powered enough to deliver substantial SPL  =  CHECK design capable of delivering 122db at 40hz @ 250watts, or 107db at 30hz @ 250watts 
  • Cost effective but highly transparent drivers  = The SB Acoustic and Seas drivers are well regarded drivers and offer excellent response curves   CHECK 
  • Cabinet size must be Wife friendly = Cabinets are manageable with an external volume of 110litres  CHECK 
  • Driers must offer smooth roll off response slopes either side of crossover points  =  CHECK 
  • The speaker must sound great = TIME WILL TELL
  • Speakers must be full range = -3db @ 33hz. My estimates have the 12.5.1 performing relatively flat to circa 25hz in room. 
HIGH FREQUENCY 


SB acoustics DIY active speaker 3 way grizzlyaudio DSP Description:  1 inch SB Acoustics Dome "Dimple" Tweeter 
Model:  SB29RDC-C00-4 
Manufacturer:  SB Acoustics 
Cost: $55inc each (An absolute bargain) 
Purchased from: http://www.essentialaudio.com.au/
FYI Scott (from essential audio) is fantastic to deal with, great service, very good prices.
Highly recommended A+
Efficiency: 93DB @ 2.83V @ 4ohms = circa 90db @ 8ohms 2.83v / 1w/1m 

Overview: 


A brilliant HF driver, equivalent to many Scanspeak drivers 6x its price. 

Check out what zaph thinks about this driver! Highly rated 

FREQUENCY CHART 

SB29RDC-C000-4-specs.gif

MID FREQUENCY 
Seas DIY active speaker 3 way grizzlyaudio DSP
Seas DIY active speaker 3 way grizzlyaudio DSP


Description:  5 inch Seas Paper Mid range 
Model: SEAS H1262 MCA15RCY 
Manufacturer:  Seas (Prestige Range)
Purchased from: http://aranmaracoustics.com.au/
Give John a call, he is always happy to help.
Cost: Circa $88ex each
Efficiency:  89.5db @ 2.83v @ 8ohms

Overview:


As used in the Troels Gravesen Poor Man 

Super smooth and efficient. A perfect match for the HF and Low freq drivers.
Crossover range will be circa 300 - 3000hz
Fantastic roll off response, with a woven dust cap for ultra low breakup.


Seas DIY active speaker 3 way grizzlyaudio DSP
















LOW FREQUENCY 


Description: 12 inch SB Acoustic Woofer

Model:  SB34NRXL75-8
Manufacturer:  SB Acoustics
Cost:  $255inc each
Efficiency:  91db @ 2.83v @ 8ohms  

Overview:

Super smooth right up to 600hz....... with controllable cone breakup starting at 1.5khz, well out of the crossover range. 

The SB Acoustic SB34NRXL75-8 is vented alignment optimised, unlike the 6 ohm version which is suited to sealed alignments, a perfect match for a 12db crossover at circa 300-400hz into the Seas MCA15RCY mid range. 


SB Acoustics Seas DIY active speaker 3 way grizzlyaudio DSP


SB Acoustics Seas DIY active speaker 3 way grizzlyaudio DSP


SB Acoustics Seas DIY active speaker 3 way grizzlyaudio DSP


SB Acoustics Seas DIY active speaker 3 way grizzlyaudio DSP





EARLY ENCLOSURE MODELLING 
WINISD has been used to calculate all base line enclosure volumes.

The design goal here was to keep the enclosure as compact as possible, without compromising on low end extension. Internal cabinet volume has been 'optimised' to provide the flattest possible response above frequency roll off.


The end result of computer modelling yields an internal cabinet volume approximately 15 litres larger the WINISD's calculation for optimal QB3-Quasi Butterworth alignment. Circa 75 litres for the SB34NRXL75-8 low frequency driver, 33.5hz @ -3db.  Its worth noting a larger volume (up to 90litres) provides only slightly more low end response 30hz @ -3db point, however the transfer function develops a dip from 50-200hz circa 0.5db, group delay also increases by 3ms at 30hz.


Vents/Ports have been modelled as dual 4inch flared ports keep air velocity below 15m/s for non audible operation down to 20hz.


Initial dimensions are as follows:


BOX OUTER DIMENSIONS
HEIGHT  770MM
WIDTH  400MM
DEPTH  450MM

INNER DIMENSION          
110.6 LITRE VOLUME
HEIGHT  734MM
WIDTH  364MM
DEPTH  414MM 

VOLUME SUBTRACTIONS
CROSSOVER BOXES (300X 300 X 80)  7.2 LITRES
DUAL 4INCH PORTS WOOFER  8.8 LITRES
BAFFLES VERTICAL 3.6 LITRES
BAFFLES HORIZONTAL  4.8 LITRES
WOOFER DISPLACEMENT  1.5 LITRES
TWEETER ENCLOSURE  1 LITRE
MID ENCLOSURE  6.3 LITRES
TOTAL SUBTRACTIONS  33.2 LITRES

TOTAL BOX VOLUME LESS SUBTRACTIONS

~ 75.8 LITRES PERFECT FOR THE SB34NRXL75-8 


ENCLOSURE MODELLING

Below I have shown the WINISD functions for the SB Acoustic 
12 inch SB Acoustic Woofer - SB34NRXL75-8... 

TRANSFER FUNCTION 

-3db @ 33.5HZ
DIY active speaker 3 way grizzlyaudio DSP


DIY active speaker 3 way grizzlyaudio DSP


WOOFER EXCURSION 

9.8mm @ 250 WATT @ 45hz 
Modelling suggests @ 300watts 10.7mm in excursion is seen, in this 75litre alignment. 
DIY active speaker 3 way grizzlyaudio DSP



PORT VELOCITY 
15.5 M/S at 250 Watt 30hz   
DIY active speaker 3 way grizzlyaudio DSP
Well below the suggest maximum of 20m/s...
Port Dimensions are modelled @ 4 inch diameter x 2, 56/58cm long @ tuning of 32hz. 
Port volume is 8.8 litres. 



GROUP DELAY 

16ms @ 32Hz Peak 

DIY active speaker 3 way grizzlyaudio DSP


Grizzly 


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POST 2 
Bring on the holidays! 


I finally had some free time to instigate the cabinet construction for my 12.5.1 speaker. A task I have been wanting to do for sometime. The carcass and all bracing has been cut and 'test assembled' (without glue) to ensure everything goes together correctly.
DIY active speaker 3 way grizzlyaudio DSP


You will note from the pictures below, I have deviated slightly from my initial design and moved away from a circular port to a slot port. Why you ask?
Well the slot port allowed me to achieve a relatively high 1st port resonance, circa 530hz (17m/s air velocity at 200watts).... which when implemented with a 4th order crossover 'should' keep any audible port resonances non audible


DIY active speaker 3 way grizzlyaudio DSP



During final port modelling (Using WinISD) I was struggling to find an acceptable balance between low port air velocity and a high 1st freq resonance with a traditional twin 102mm pipe solution. The twin 102mm port solution provided great air velocities, 17m/s at a full 200watts, but the 1st resonance freq of the port(s) was too close within the woofers rendering spectrum. As stated previously utilising a slot port provided more opportunity/scope to achieve this balance, as 'core' sizing is completely customisable in measurements of millimetres. 

The slot port solution has the added benefit of providing increased cabinet strength and rigidity when compared to a traditional circular port solution, which does little for cabinet structure. 

Still to come...... 
  • Calculate total bracing volume 
  • Re calculate port length based on final bracing volumes 
  • Cut 2 slot ports for each enclosure 
  • Routing drivers into baffle
  • Routing / Windowing all internal braces 
  • A complete cabinet disassemble and reassemble with glue and all correct fixings 
  • Routing front baffle sides for improved tweeter dispersion 
  • Routing all cabinets edges for a flush and trim finish
  • Installation of wiring and speaker terminations 
  • Full sand 
  • Apply primer 
  • Have the cabinets professionally sprayed (Once everything is tested!!)
Grzzly

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POST 3 
CUTTING BAFFLES

So now that I had the speaker carcass and major braces cut, the next step was to 'window' cut all the baffles ready for driver installation.

Understanding my end goal is to create speaker cabinets which are inert as possible, you will see I continued the use of 18mm MDF timber for the construction of all horizontal and vertical support braces used internally of the speaker carcass. On average horizontal braces are to be fixed at 100-150mm intervals.



DIY active speaker 3 way grizzlyaudio DSP

This spacing strategy seems to provide a decent compromise between cabinet rigidity (low resonance) and going over board. I must admit though, the cabinets were becoming seriously heavy!! and once complete will require 2 strong people to lift into place.

In addition to the horizontal baffling, I cut 50mm deep vertical braces (6 per section, or 3 per wall) to reinforce the non reinforced sections of the side walls between the large horizontal braces. My theory here (based on my experience with my subwoofer build) was the "timber ribbing" would help make the unsupported wall sections inert. From what I could tell it was a good strategy, a quick knuckle test delivers a solid thud.. even without final fixing! 


WOOFER BRACES



CUTTING BAFFLES
So now that I had the speaker carcass and major braces cut, the next step was to 'window' cut all the baffles ready for driver installation.

Understanding my end goal is to create speaker cabinets which are inert as possible, you will see I continued the use of 18mm MDF timber for the construction of all horizontal and vertical support braces used internally of the speaker carcass. On average horizontal braces are to be fixed at 100-150mm intervals.

This spacing strategy seems to provide a decent compromise between cabinet rigidity (low resonance) and going over board. I must admit though, the cabinets were becoming seriously heavy!! and once complete will require 2 strong people to lift into place.

In addition to the horizontal baffling, I cut 50mm deep vertical braces (6 per section, or 3 per wall) to reinforce the non reinforced sections of the side walls between the large horizontal braces. My theory here (based on my experience with my subwoofer build) was the "timber ribbing" would help make the unsupported wall sections inert. From what I could tell it was a good strategy, a quick knuckle test delivers a solid thud.. even without final fixing! 
DIY active speaker 3 way grizzlyaudio DSP



Bracing DIY active speaker 3 way grizzlyaudio DSP



Bracing DIY active speaker 3 way grizzlyaudio DSP


Bracing DIY active speaker 3 way grizzlyaudio DSP

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POST 4
MID SECTION BAFFLE CUTTING 
All cabinet baffling as covered in my last speaker post has been cut from 18mm MDF, the strategy and focus is to create an speaker cabinet which is inert and as resonance free as possible.


As per the woofer baffles, the mid section baffles were cut with simple rectangular window cuts. 50mm wide on the outer edges with a 18mm solid section for the centre brace to fix to. The top sections are much larger allowing for the mid driver cabinet assembly. 

The mid section braces double as enclosure walls for the mid driver cabinet. If you refer to the adjacent photo you can see the mid section outline drawn on the MDF in pencil. <<
Currently all braces and sections are sitting unsupported in place. I am hoping once these sections are glued and screwed into place, the cabinet should be extremely inert and resonance free.   

MID CABINET PORT 
In the time I had available, I also managed to cut the mid port into the mid driver cabinet rear wall. 


Bracing DIY active speaker 3 way grizzlyaudio DSP

To complete the mid driver port installation, I need to orientate and position the PVC port in place and cut an opposing hole into the rear wall of the speaker. This will allow the port to pass through the rear wall of the speaker cabinet. 

This task will be instigated once the cabinet is permanently glued and screwed together. I will then route both port exits into the mid cabinet interior and on the rear exterior wall of the speaker cabinet.  

See below some pictures of the work completed today......

WHAT THE NEXT STEP 
Next, I need to complete a full cabinet disassemble, ready for a permanent assembly using glue and screws. This stage will include the installation of the small ribbing braces which I covered in the last speaker blog post. 

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POST 5 
FINAL BOX CALCULATIONS

OK, so prior to sealing up the cabinets with the baffle boards, I thought it was prudent to recheck my enclosure volume calculations, just to make sure everything was in order and accurate. During the build I made some notable 'artistic' design changes, the most obvious was the adoption of a slot port system and some minimal internal bracing deviations, so this made sense.   

My first step in this process was to visit www.diyaudioandvideo.com. This site provides a host of handy DIY speaker building calculators. The one I was after was after the driver displacement calculator! 

SEAS MID DRIVER DISPLACEMENT 


Effective Cone Diameter = 80 mm


Mounting Depth = 67.5 mm 


One-way, Linear Excursion (Xmax) = 1.7 mm 


Magnet Diameter = 90 mm 


Magnet Height = 27 mm 


Front Baffle Thickness = .75 in 


Flush Mount = Yes 







Once all the numbers are punched in, the calculator does the hard work and produces the magic displacement figure....... The software provides a SEAS displacement volume of  0.22 litres. 


So taking my 'asbuilt' mid cabinet volume of 3.192 litres and subtracting 0.22 litres driver displacement provides me with an overall net mid cabinet volume of 2.97 litres... perfect!! and in line with the modelling provided by win ISD


WINISD MODELLING @ 2.97 litres
















WOOFER DISPLACEMENT 



Effective Cone Diameter = 260 mm
Mounting Depth = 146 mm 


One-way, Linear Excursion (Xmax) = 10 mm 


Magnet Diameter = 180 mm 


Magnet Height = 62 mm 


Front Baffle Thickness = .75 in 


Flush Mount = Yes 

 



The displacement calculator in this instance, spits out 2.47 litres displacement. 

OK, so now that I have the displacement figures for both the mid and woofer, I can reconcile the volume of the main cabinet. You will note, I did not measure the tweeter displacement, because its net displaced volume is negligible. 


ACTUAL INTERNAL CABINET VOLUME 
Internal cabinet volume..........................106.7 litres 

VOLUME REDUCTIONS 

Slot Port (54x344x325mm)......................6 litres (outside dimensions) 
Woofer Displacement...............................2.8 litres    
Mid Enclosure..........................................4.14 litres 
Mid Port....................................................7.8 litres 
Tweeter enclosure .....................................0.75 litres each 
Horizontal braces.....................................circa 5-6 litres 
Vertical braces (There are 3 types) 
Type 1    2 x 115x274x18mm....................1.134 litres total 
Type 2    3 x 36x18x344mm......................0.67 litres total 
Type 3    1 x 104x18x268mm....................0.5 litres 
Type 4    1 x Woofer 18mm fixing brace behind cutout ................1 litre 

So to calculate a final working volume, I now need to take overall cabinet volume and subtract all calculated/known reductions. (106.7 - 30.794) = circa 75.9 litres, with extras I anticipate total usable volume will be 75 litres exactly. 


Just for consistency I have remodeled the SB acoustic 12inch.... based on the above 76 litre net enclosure volume calculation. As expected the plot is essentially identical to the 75 litre plot completed during the cabinet design phase. -3db is 34hz.... which is a good thing ;) 




















SO WHAT DOES ALL THIS MEAN? 
It simply means my build thus far has been successful. I can now mount the speaker baffle boards ready for driver population. Here's a few shots of the speakers glued and screwed. 

The cabinets are only missing the front baffles boards, mid PVC port and slot boards.....plus termination hardware of course.  


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POST 6 
FINAL POST 


The 12.5.1 3 way active speaker build took about 9 months to complete. Of this time 6 months was dedicated to design and procrastination, while the actual physical build process only took 3 months. All work was completed by myself on the weekends between my normal 9 to 5'er. 

I must say I am actually quite proud of myself looking at the completed speaker. The 12.5.1 is my first DIY speaker active or passive, and the cabinet finish and sound quality is for excellent especially considering my knowledge base, wood-working skills and the overall monetary investment made. 

Would I have done things differently if I had my time again? Sure a few, but I'll keep them under my sleeve for next time ;)..... 


Lets start with a quick recap of the 12.5.1 design goals I posted way back in July 2013... 


DESIGN GOALS 

My design goals were simple; construct a "cost effective" passive/active monitor style speaker system which offeres superior levels of: 
  • Transparency 
  • Sensitivity 
  • Full range performance  
  • Dynamics 
  • Power Handling 
  • Musicality 

So I guess your asking did I achieve these goals? right?

INITIAL 12.5.1 LISTENING THOUGHTS
To answer whether the 12.5.1 has achieved the design goals above I will provide a quick overview of what they sound like, or at least sound like to me.... Describing sound is always a difficult task at the best of times and to be honest somewhat futile. Sound is subjective and therefore my listening thoughts and opinions detailed in this blogpost are accompanied by simple REW measurement plots, which provide an objective frequency performance result for the 12.5.1's within my lounge room space. 

I should firstly state I don't generally like 'flat' response speakers. Although frequency flatness is a good place to start and offers a platform for speaker performance comparison, I often find speakers which exhibit end to end flat spectral responses ultimately lack bass weight and sound invariably forward and harsh. You will see from the REW measurements below, I have purposely over emphasised the bass response of the 12.5.1 by circa 3db to provide better overall spectrum balance and bass weight to suit my musical preference. Ideally I would have lower end frequencies even more emphasised by say +4-6db to provide further enhanced bass definition, weight and impact. 

Please note I lost my in room REW measurements.... As I sold these speakers I am unable to take new measurements. The speakers were essentially +/- 3db in room at listening from 200hz-20khz... 


HIGH FREQUENCIES 

The 12.5.1 is detailed and presents a natural vocal and wide holographic stereo image. The SB Acoustic SB29RDC-C000-4 tweeter renders sweetly without being harsh or creating any audible 'shrill' across its spectrum. The driver sits more on the darker side of neutral... confirmed by my REW sweeps. 


In room REW frequency measurements (measured circa 10 degrees of axis) show a relaxed top end above 15khz which 'to me in my room' sounds very musical and detailed enough not to want for any more high frequency information. I will take some nearfield on axis direct measurements in time to understand the off axis effect on results... 

MID FREQUENCIES

The Seas SEAS H1262 MCA15RCY mid range is an excellent driver, it presents with a natural neutral character, neither warm or forward. Vocals sound well balanced, clear and natural, just as the manufacturers response charts would suggest. The midrange is quite impressive offering a noticeably transparent and detailed render. 

The 12.5.1 speakers imaging is pin point and extremely wide. I fail to hear any negative implications or degradation of holographic presentation as a consequence to the 12.5.1's somewhat wide 380mm baffle. In fact listening to a few test tracks like Madonna's Express yourself, the musical image is projected way outside and in front of the outer edges of the 12.5.1 baffles...... some 2-3 meters in distance. Impressive indeed. 


BSC (baffle step compensation) employed in the 12.5.1 is applied from 300hz which also happens to be the exact crossover point between the high and mid drivers. I compensated for a full space 6db loss...combined with driver efficiency matching final mid/tweeter attenuation figures were 8db attenuation to the mids and 3db attenuation on the tweeters. Overall speaker sensitivity is therefore slightly reduced, however a normalised response is more important than overall speaker efficiency. I estimate circa an efficiency of 89-90db in its finished active state. Its also worth noting initial driver delay settings based on rough physical measurements have been set as 0.12ms for the tweeter and 0.06ms for the seas mid. 



THE BUSINESS END 
Unfortunately my room does not lend itself to ideal bass reproduction. As such bass weight is not as forthright as I would like from the 12.5.1 (in my room & without equalisation) due to 'irritating' and 'considerable' room nulls at 108hz and 40hz.... Unfortunately there's little I can do to 100% negate these nulls other than move my speakers to a different room.

What I will say is with a little persistence and persuasive equalisation I have been able to produce really amazing bass weight and extension from the 12.5.1's. 

To enhance bass extension and bass weight I run some permanent parametric equalisation at the following freq's and gains to provide a nice fat bottom end.... I must say I am pretty happy with the bass response with these settings.  

  • 108hz +6db (more so to negate the room null)
  • 40hz +3db (again to negate room nulls) 
  • and 30hz +3db.... for good measure and taste....... 
At some stage I will listen to the 12.5.1's in an alternate room to hear an honest render of the 12.5.1's bass capabilities. 

In room measurements show the drivers are -8db at 20hz in room. 

MUSICALITY 
Speaker musicality is excellent, the speakers sound open, detailed and quick on their feet. Bass at the initial stage (2 hours in) of operation is tight, extended, tone rich, punchy with no audible overhang or group delay. However without stating the obvious the bass nulls inflicted by my living room really hurt bass impact & dynamics. The REW measurements detail the extent of the problematic nulls.

The SB acoustic SB34NRXL75-8 driver shows no audible signs of compression at normal listening levels, I.e. <95db, I haven't pushed the speakers harder yet. With no equalisation in room bass extension is decent with the speakers producing circa -8db at 20hz as independently operated/measured speakers, with both speakers operational REW measures the 12.5.1's essentially flat response to 25hz......give or take the room interactions.

I will post more plots once the speakers have had a few hours of decent excursion to loosen up a little.

So am I happy with the 12.5.1...? Yes I am. 
I believe all but the efficiency goal has been achieved, as originally I was after a +90db speaker.... I believe the 12.5.1 falls slightly short of that.

Overall the speaker performs very well offering good dynamics, excellent extended bass response, musicality and transparency. I 'think' if I had to go hifi shopping to buy something which delivered as much quality sound as this setup I would need to spend upwards of $5000+....... 

BUILD INVESTMENT 
My total investment was $800inc in drivers, $60inc in MDF timber, probably $150 in misc items and $200inc in Symetrix DSP (I actually purchased two DSP units but only needed one..... the spare will be used when I go 4 way! lol) So all up I spent about roughly $1300inc gst + a decent whack of my time.

BUILD PICTURES 

DIY Speaker Active

DIY Speaker Active

DIY Speaker Active

DIY Speaker Active

DIY Speaker Active

DIY Speaker Active

DIY Speaker Active

DIY Speaker Active

DIY Bafflle speaker

DIY Bafflle speaker



Active Speaker DIY 12 inch
Active Speaker DIY 12 inch
Active Speaker DIY 12 inch
Active Speaker DIY 12 inch

Active Speaker DIY 12 inch



Active Speaker DIY 12 inch



Active Speaker DIY 12 inch
Active Speaker DIY 12 inch






Active Speaker DIY 12 inch

Active Speaker DIY 12 inch
Active Speaker DIY 12 inch

Finished DIY speaker


Finished DIY speaker



Active speaker DIY

Active speaker DIY



3 comments:

  1. Hi. Do you think there's any scope for keeping the cabinet volume but arranging the drivers in a different layout, say the bass on top, and mid and tweeter forward, akin to the Focal SM9 (although i'm aware the one on the SM9 is a passive radiator). This sort of shape would fit in much better in my living room.

    ReplyDelete
    Replies
    1. Hi Nathan,

      The frequencies produced by the SB acoustics woofer in this speaker alignment are up to 300hz+ depending on the electronic crossover implemented, I.e. 6db, 12db, 24db, 48db.

      Its typically agreed, bass frequencies below 80hz are not easily located and are omni-directional.

      This speaker alignment sees the woofer producing frequencies much higher than subwoofer frequencies... I.e. >+80hz. as such I would not recommend firing a woofer vertically up if it is to reproduce frequencies above 80hz.

      You will be missing considerable acoustic information.
      My 2 cents

      Delete
  2. Hi,
    I am motivated with your LS design and keep serious interest to make a similar L.S Design. Let me know if I can go with Sealed enclosure design by using 12 inch woofer from SB acoustics (SB Acoustics SB34NRX75-6 12" woofer).

    Can I make 3 Way Monitor design in a sealed enclosure by using your enclosure
    design? I like deep extended Bass response for LS and thus opted for 12 in drivers.

    Kindly help and advise.

    Regards,
    Sam

    ReplyDelete