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Multi-Way Conventional loudspeakers with crossovers

Yet another cost effective main speakers build
Yet another cost effective main speakers build
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Old 14th September 2019, 01:53 AM   #1
JRiv is offline JRiv
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Smile Yet another cost effective main speakers build

Hi all, new here but an oldie around the 2CH audio, here is yet another cost effective compact main speakers build to start with.

Brief intro:
The long story short, after playing around with 3-Way, 2-Way(commercial and DIY), passive and active configurations, I settled up for 2-Way 10" Pro mid/woofer and 1" compression driver with fully active crossover/DSP, also I will mate them with subwoofer(s) during serious listening sessions as usual.

Also the project aims to be an cost effective, very simple to build compact main towers, efficient and SPL capable while holding dynamics with relatively low distortion hopefully.

About the design:
This design uses a single 3/4" 4'x8' MDF sheet for a pair of speakers, they can be painted or covered with standard laminate of the color/texture of choice, in my case I chose lightly textured black matte standard laminate #909, as I'm not even average at painting with detailed terminations .

The drivers/parts of my choice are as follow:
FaitalPRO LTH102 Tractrix Horn.
B&C DE250-8 CD, (optional: any suitable/tested clone).
PRV 10W650A Woofer, (optional: Eminence Delta 10A).
Audyn Q4 33uF 400V MKP, (CD protection capacitor).
Speaker Cabinet Port Tube 4" ID x 4-3/8" L, (~3.88" ID x 2.75" L cut).
Neutrik NL4MPR 4-Pole Connector.
Penn-Elcom F1686 Rubber Foots.

Some WinISD modeling of the project
F3 comparison vs sealed enclosure:
F3_vs_Sealed.png

SPL with just 100W, 30Hz LR4 HPF on the ported speaker:
100W_&_30Hz_HPF_LR4.png

SPL with 300W, 80Hz LR4 HPF on both speakers:
300W_&_80Hz_HPF_LR4.png

Speaker crossover/management:
The speaker crossover/management will be provided by the DBX DriveRack PA2 that I already have, also I'm planning to start with about 1500Hz xover point and take some REW measurements as I did on my previous builds, though my small room of 8'H x 10'W x 9'D is far from being ideal and have no treatment at all.

The Cutlist preview(assumes the MDF sheet measures 49"x97"):
Cutlist_Preview.png

The wanted front ported black-matte finish:
Model Black-Matte Laminated.png


All images can be found HERE


More to come soon.
Regards.
Attached Images
File Type: jpg 1.jpg (255.0 KB, 955 views)
File Type: jpg 2.jpg (190.2 KB, 1035 views)
File Type: jpg 3.jpg (217.8 KB, 1005 views)
File Type: jpg 4.jpg (188.4 KB, 997 views)
File Type: jpg 5.jpg (295.3 KB, 921 views)

Last edited by JRiv; 15th September 2019 at 02:25 PM. Reason: Add images link
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Old 14th September 2019, 04:21 AM   #2
LineSource is offline LineSource  United States
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The $66 10" PRV 10W650A is not a woofer.
You will not get deep bass with Fs=72Hz and Qts= 0.46, even in a large volume box.

Optimum Cabinet Size PRV 10W650A (determined using BassBox 6 Pro High Fidelity suggestion)
Sealed Volume 11.03 ft.
Sealed F3 191.7 Hz
Vented Volume 40.71 ft.
Vented F3 52.81 Hz
===========
Does your DBX DriveRack PA2 provide time delay to match the horn and midbass physical offsets? Shallow waveguide are often selected because their depth closely matches the midwoofer voice coil delay.
===========
===========
The $77 12" Dayton DS315-8 paper woofer with Fs=25Hz is popular because it is a true midbass(F3=37Hz) which matches the SEOS12 waveguide depth, and when slightly counter sunk into the baffle, also closely matches the SEOS15 and $14 PRV-WG35-25 waveguide depths. The flat impedance and extended low frequency SPL curve on the $65 Peerless DFM-2544R00-08 compression driver simplifies 1000-1200Hz passive crossovers.

Optimum Cabinet Size Dayton DS315-8 (determined using BassBox 6 Pro High Fidelity suggestion)
Sealed Volume 0.93 ft.
Sealed F3 60 Hz
Vented Volume 1.9 ft.
Vented F3 37 Hz
Attached Images
File Type: jpg 1in shallow horns.jpg (171.7 KB, 189 views)
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Old 14th September 2019, 06:16 AM   #3
JRiv is offline JRiv
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Quote:
Originally Posted by LineSource View Post
The $66 10" PRV 10W650A is not a woofer.
You will not get deep bass with Fs=72Hz and Qts= 0.46, even in a large volume box.

Optimum Cabinet Size PRV 10W650A (determined using BassBox 6 Pro High Fidelity suggestion)
Sealed Volume 11.03 ft.
Sealed F3 191.7 Hz
Vented Volume 40.71 ft.
Vented F3 52.81 Hz
===========
Does your DBX DriveRack PA2 provide time delay to match the horn and midbass physical offsets? Shallow waveguide are often selected because their depth closely matches the midwoofer voice coil delay.
===========
===========
The $77 12" Dayton DS315-8 paper woofer with Fs=25Hz is popular because it is a true midbass(F3=37Hz) which matches the SEOS12 waveguide depth, and when slightly counter sunk into the baffle, also closely matches the SEOS15 and $14 PRV-WG35-25 waveguide depths. The flat impedance and extended low frequency SPL curve on the $65 Peerless DFM-2544R00-08 compression driver simplifies 1000-1200Hz passive crossovers.

Optimum Cabinet Size Dayton DS315-8 (determined using BassBox 6 Pro High Fidelity suggestion)
Sealed Volume 0.93 ft.
Sealed F3 60 Hz
Vented Volume 1.9 ft.
Vented F3 37 Hz

Hi LineSource, thank you for your suggestions and observations about the bass response and FS of this drivers, however since I have a local distributor of this brand I've listened few of the 10" and this drivers drove me attention from the first time I've listened to them, as they can play loud and clear even when pushed, hence I've selected the same drives for this speakers project.

I agree this speakers will be a bit bass shy and will struggle playing below ~50Hz, however this speakers will be crossed at 60Hz LR4 and mated to an existing DIY UM18-22 5FT^3 sealed subwoofer temporarily, but they will be actually crossed around ~80Hz LR4 when mated to two B&C 21SW152-4 11FT^3 subwoofers tuned to around 19Hz, but this is another project, the system is for 99% music listening.

As fort the DBX DriveRack PA2 alignment delay, yes it provides up to 10ms alignment delays per channel, additionally 8-Band PEQ's with bell, low and high shelf for speaker tuning, also several handy processors.

Again thanks for the Dayton DS315-8 recommendation, however I'm more of a Pro Audio driver fan, also want to limit the mid/woofer size to 10" max, as the only spacer left of my room is reserved for the two 21" future subwoofers project.

Regards
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Old 14th September 2019, 08:26 PM   #4
JRiv is offline JRiv
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Here are some of the materials I will start working with tomorrow, I still have to cut the 8 pieces used for the top, bottom and the 2 windows style braces per box, one between the horn and midwoofer and one between the longest box part to minimize resonances.

I will put Epoxied 6-32 T-Nuts for the midwoofers(this stamped steel woofers have small mounting holes), with Hex socket-head black oxide screws, and same T-Nuts for the horns, but with Alloy Hex flat-head black oxide screws.

I also have some 10-32 Hurricane Nuts that are much stronger, but they looks too large compared to the tiny mounting holes this woofers have, and I didn't liked how the bulging woofer flange looks after inserting such screws with large head caps on my previous attempts.

More to come soon.
Regards
Attached Images
File Type: jpg 6.jpg (171.7 KB, 139 views)
File Type: jpg 7.jpg (204.6 KB, 72 views)
File Type: jpg 8.jpg (210.0 KB, 76 views)
File Type: jpg 9.jpg (216.6 KB, 62 views)

Last edited by JRiv; 14th September 2019 at 08:49 PM.
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Old 16th September 2019, 12:31 AM   #5
JRiv is offline JRiv
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Update
Usually I'm that guy who start a wood project with some disasters before anything else.

Unfortunately the MDF sheets the guys sold me at the local store were 5/8"(16mm) instead 3/4"(19mm) which is my preferred thickness for speaker projects, somehow the guy who grab and cut the MDF sheet did a mistake, but I was confident enough to put the pieces in the trunk and sign the agreement without check the material, so shame on me.

Secondly, as part of the project goal, I did purchased some cheap router bits on eBay with top/bottom bearings to save some bucks, but it turned that the 1/4" router bit did bent and destroyed my router plastic base with a big bang, glad I always wear protection glasses when working with power tools.

Fortunately I could easily fix the router base with a 1/4" panel I have lying around until I find the original, however at this point I'm not sure If I should continue the project with this 5/8" thickness MDF .

Should I have to worry if I go with this 5/8" MDF for the boxes?, will the resonance be negligible if I use 2 or 3 windows style bracing per enclosure?

Sorry for asking such questions, I just like to overbuild my enclosures and that 5/8" MDF sheet still worries me a little.

Regards
Attached Images
File Type: jpg Router_Bit_Bent_2.jpg (886.4 KB, 92 views)
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Old 17th September 2019, 01:34 AM   #6
JRiv is offline JRiv
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Update
Hi, since I already have this 5/8" MDF, and already cut, I just decided to go and buy another 5/8" MDF sheet to use double thick of about 1.25"(32mm), this slightly changed the box specs but in a really good way, the box stiffness will increase thus reducing the resonances, also I will skip the T-Nuts as there will be enough MDF meat for the screws to grab.

As for the Router bit accident, it turn out that those bits shanks are too long for my router(1.5"), preventing them to enter all the way down the Router collet letting about half inch out, hence the vibration increased rapidly bending the bit in a blink, so lesson learned and will stay with the shanks of 1/4" x 1" long which is the max my router can handle.

Regards
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File Type: jpg 1in_long_shank_.250.jpg (170.3 KB, 92 views)
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Old 18th September 2019, 05:05 PM   #7
JRiv is offline JRiv
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Update
Hi, after thinking and playing around with WinISD, and since I'm a bit picky regarding speaker box wall thickness, I ended up ordering another same MDF sheet to make a 1.25" MDF sandwich plus 2 window style braces per box, so I just gave them the same cutlist for the cuts.

However, the MDF sheet was from a different manufacturer and it measured exactly the 48x96 unlike the previous 49x97 material, so unfortunately the speakers will be 36" tall instead the planned 37"(without feets), but I think is not a big deal.

The new box measures will be 36"H x 12"W x 14.5"D approximately(without feets and laminate), also I estimate for the box weight to be around 50~60Lbs without drivers and about ~70+Lbs after drivers, though I will take final weight after project finished if possible.

The MDF sandwich bonding is now cooking, but I will post more pics of the box progress soon.


Regards
Attached Images
File Type: jpg Double_MDF.jpg (150.6 KB, 68 views)
File Type: jpg TB3_Spread.jpg (136.2 KB, 39 views)
File Type: jpg 1in_To_Trim.jpg (188.2 KB, 61 views)
File Type: jpg Wood_Bonding.jpg (174.4 KB, 64 views)
File Type: jpg Weight_Cooking_Glue_.jpg (251.7 KB, 73 views)
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Old 19th September 2019, 07:37 AM   #8
Mazza is offline Mazza  Australia
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JRiv,
I see you have the MB Acoustics DE250-P clone. Did you measure these on the horn yet?

I got two of these last week and they were both so poor in their measured response on a SEOS-12 I got a full refund from the seller.

Just saying as it would be a shame if you have units from the same batch/problems.

Perhaps they'd be fine in a non-critical PA system, but for my home use the units I've measured were completely unviable.

Sorry to be a downer on your nice build. Good luck!

Cheers.
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Old 19th September 2019, 02:46 PM   #9
Mazza is offline Mazza  Australia
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My measurements are posted here...
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Old 19th September 2019, 06:28 PM   #10
JRiv is offline JRiv
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Quote:
Originally Posted by Mazza View Post
JRiv,
I see you have the MB Acoustics DE250-P clone. Did you measure these on the horn yet?

I got two of these last week and they were both so poor in their measured response on a SEOS-12 I got a full refund from the seller.

Just saying as it would be a shame if you have units from the same batch/problems.

Perhaps they'd be fine in a non-critical PA system, but for my home use the units I've measured were completely unviable.

Sorry to be a downer on your nice build. Good luck!

Cheers.


Hi Mazza, thanks for the input about the MB DE250-P clones, I originally wanted the PRV D290Py-B but it was unavailable at my local PRV distributors, then I saw this DE250-8 clones on ebay and after searching for info and measurements on this particular clones with very little results at that time, I decided to pull the trigger, although I was still in doubt about they sound and build quality. but I did a quick test by ear on the LTH102, and to my ear they sounded somewhat good with smooth top end, however this was pure speculations here.

I opened the drivers and they look exactly like yours, very poor machining on the screws and diaphragm connector holes, no foam pad in the back cup and the "Polyimide" diaphragm color is the same, plus I noticed some fine hairs of glue left-overs near the diaphragm VC that I carefully removed with an eyebrow tweezers.

I was about to take some measurements on-axis of both clones + LTH102 to see what they can bring, but after opening them I concluded to just buy the PRV D290Py-B or something else online.

Again thanks for the really useful information about this particular DE250 clones.

Regards
Attached Images
File Type: jpg IMG_20190919_115258595.jpg (217.6 KB, 78 views)
File Type: jpg IMG_20190919_115314182.jpg (185.3 KB, 59 views)
File Type: jpg IMG_20190919_115346932.jpg (309.2 KB, 50 views)
File Type: jpg IMG_20190919_115400752.jpg (182.9 KB, 51 views)
File Type: jpg IMG_20190919_121354094.jpg (199.1 KB, 42 views)
File Type: jpg IMG_20190919_121412739.jpg (146.1 KB, 44 views)

Last edited by JRiv; 19th September 2019 at 06:29 PM. Reason: Adding images.
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