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8" Active Studio Monitor

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Category: Plans
Forum Name: New Projects Forum
Forum Description: Forum for new speakerplans projects, in memory of Tony Wilkes, 1953 - 2014
URL: https://forum.speakerplans.com/forum_posts.asp?TID=102417
Printed Date: 04 December 2022 at 7:33am
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Topic: 8" Active Studio Monitor
Posted By: vertx
Subject: 8" Active Studio Monitor
Date Posted: 18 August 2018 at 10:15am
Now I'm back working again I've got the opportunity to build a few of the designs I had the time to CAD when I was unemployed LOL

I've just ordered a pair of Fusion Amp FA123s and will be ordering a pair of Volt BM228.8s asap.

To follow will be a pair of Scan-Speak D2606/922000 with the plan to put together these:












Replies:
Posted By: vertx
Date Posted: 28 August 2018 at 11:57am
Amps are here!




Posted By: VECTORDJ
Date Posted: 30 August 2018 at 10:49pm
A+


Posted By: 4AC
Date Posted: 31 August 2018 at 10:33am
Awesome! What freq have you tuned the ports to?

Please share your thoughts/opinion/experiences of the new Hypex's.


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uǝɿɿɐʌǝ6ɯo sı ʇsʞǝʇ ǝzǝp


Posted By: fatfreddiescat
Date Posted: 31 August 2018 at 10:54am
Are you intending to add bracing? - would recommend some to push the panel resonances up to high enough frequency so as not to be affected by the 8".


Posted By: vertx
Date Posted: 31 August 2018 at 11:00am
Originally posted by 4AC 4AC wrote:

Awesome! What freq have you tuned the ports to?

Please share your thoughts/opinion/experiences of the new Hypex's.


Will do. Only just got a Mini USB cable from work today (required for use with Hypex Filter Designer/Fusion Amps) so will maybe try give my Volt 8" coax a run with them to compare against matrix XT800 which I'm current running on them.

Volume is 23.4L, tuning is 43hz. Max vent velocity is 32 at 150w but down at 24 when xmax is exceeded anyway.

Just got a quote back for CNC so will be cracking on with this over the next few weeks!


Posted By: Meat
Date Posted: 31 August 2018 at 11:11am
Nice, I hadn't seen that the new Hypexs were out. Very trendy stuff.


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Don't test the champignon sound


Posted By: vertx
Date Posted: 01 September 2018 at 12:53pm
Originally posted by fatfreddiescat fatfreddiescat wrote:

Are you intending to add bracing? - would recommend some to push the panel resonances up to high enough frequency so as not to be affected by the 8".

Yeah I'll probably add some in, don't have any in the CNC plans but might just cut up a few bits as I go.




Posted By: vertx
Date Posted: 01 September 2018 at 1:05pm
Connected the FA123s to my existing Volts to do a bit of subjective comparison against my XCA28/Matrix XT800 I'm currently running for processing/amp combo.

Ran the FA123 CH1/2 in bridge into the 4ohm volts.

Plenty of headroom.
Less sub.
Better transients, tighter overall sound.
Very slightly more "essy", but could just be a more dry sound, less "warm" than the XT800.
Different stereo imaging, more depth, less width?

Sure the FA123 will do even better when bridged into an 8ohm load into the BM228.8's






Posted By: vertx
Date Posted: 02 October 2018 at 12:50pm
Got the parts back from CNC for this and another 8" cab I'm working on. Tweeters have arrived too.

Planning to glue and clamp only, no screws this time around. Hoping to have cabs together this weekend time allowing. Volt BM228.8 will probably be another 2 weeks.




Posted By: vertx
Date Posted: 11 October 2018 at 12:04pm
All parts arrived now. Will be getting stuck in this weekend weather allowing Smile





Posted By: vertx
Date Posted: 14 October 2018 at 11:01am
Busy weekend Smile

Had to run down to the hardware store to get some bigger clamps part way through gluing the first cab as my normal quick grips were too short LOL


















Posted By: mini-mad
Date Posted: 14 October 2018 at 4:21pm
...the Mrs doesn't look to impressed.... prob the fact you unplugged her dishwasher to test them!!




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If it sounds like a gorilla is trying to escape, turn it down.


Posted By: vertx
Date Posted: 16 October 2018 at 11:54am
This is the response, no smoothing, at I guess 4pi ? Some EQ adjustments made, and I'm confident there's still loads of room for improvement.

Measured on back facing sky, about 1m off the ground on milk crates. The 5db drop off in low end flattens out quite nicely in the small studio. When the high pass is down around 20hz there is a surprising amount of low pressure (current settings have it at 30hz high pass)



This is the seperate woofer/tweeter response, and then the overall sum after alignment. Electrical crossover at 2.1khz, acoustic crossover at 2.2khz:




Posted By: vertx
Date Posted: 16 October 2018 at 12:25pm
Got them in the studio, pretty large compared to my previous ones but stereo image is way better




Short video:

https://drive.google.com/file/d/1cjUlwCxE09mUhfXW2R6WIo0T4rqFdn3k/view?usp=sharing



Posted By: Mircea Bartic
Date Posted: 16 October 2018 at 3:42pm
excellent work !


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general manager & head designer at nexus-acoustics research
http://www.facebook.com/nexus.acoustics.research" rel="nofollow - http://www.facebook.com/nexus.acoustics.research

Ex Nexus_3


Posted By: concept-10
Date Posted: 16 October 2018 at 6:11pm
perfect Smile


Posted By: Sypa
Date Posted: 16 October 2018 at 6:47pm
Is there one plate feeding both or? 
How did it turn out regarding the final price ? 
Reckon not cheap, but atleast you know you have quality components. 


Posted By: odc04r
Date Posted: 16 October 2018 at 7:28pm
Looking nice, well done. Might benefit from baffle step compensation under ~100Hz if you don't mind losing some headroom over the rest of the spectrum


Posted By: vertx
Date Posted: 17 October 2018 at 10:38am
Originally posted by Sypa Sypa wrote:

Is there one plate feeding both or? 
How did it turn out regarding the final price ? 
Reckon not cheap, but atleast you know you have quality components. 


There is one FA123 per cab. 100w channel for tweeter, 250w via bridged channels on same board.





Posted By: vertx
Date Posted: 17 October 2018 at 10:49am
Originally posted by odc04r odc04r wrote:

Looking nice, well done. Might benefit from baffle step compensation under ~100Hz if you don't mind losing some headroom over the rest of the spectrum


In the form of a low shelf type boost in the DSP?

I've heard the term baffle step before but thought it was more about chamfered baffle edges to help with diffraction?


Posted By: odc04r
Date Posted: 17 October 2018 at 12:00pm
Yeah, it's a low shelf boost. Chamfered edges is a different effect. The width of the cabinet allows some wavelengths to be reinforced when they leave the driver, basically they "see" the baffle width. When the wavelength gets larger than some number (probably quarter wavelength>cabinet width) then the baffle no longer helps to reinforce the frequency and you get a drop in output as it becomes more omnidirectional.

You need to balance it out with the potential reinforcing effects of the room and cabinet positioning too. I.e. if you put them close to a wall or corner you may not notice as much. As always adjust to suit.


Posted By: DMorison
Date Posted: 17 October 2018 at 1:52pm
Originally posted by vertx vertx wrote:

Originally posted by odc04r odc04r wrote:

Looking nice, well done. Might benefit from baffle step compensation under ~100Hz if you don't mind losing some headroom over the rest of the spectrum


In the form of a low shelf type boost in the DSP?

I've heard the term baffle step before but thought it was more about chamfered baffle edges to help with diffraction?

The baffle step on a cab of about your size (I'm guessing in the ballpark of 250mm wide?) will be about 460Hz; as odc4r says its based on the 1/4 wavelength.

It happens due to the transition from the driver effectively being in half space when wavelengths are small relative to the size of the baffle (ie upper mids on up) vs in whole space when the wavelengths are big enough to wrap around the cab (low mids on down).

Your fellow Aussie Rod Elliott has written a good summary of it: http://sound.whsites.net/bafflestep.htm" rel="nofollow - http://sound.whsites.net/bafflestep.htm

The edge chamfering/diffraction effect is sort of related - for frequencies that have a certain relation to the cab dimension, a sharp edge can cause even more of a reflection than just the standard baffle step effect, so rounding the cab edge can help offset that.

Tolvan Audio's free "Edge" software can model both the baffle step and edge effects as well: http://www.tolvan.com/index.php?page=/edge/edge.php" rel="nofollow - http://www.tolvan.com/index.php?page=/edge/edge.php .

Obviously, moving a cab relative to larger boundaries (ie desk, walls etc in your studio) will affect things - at the larger scale, room gain will offset the effect for lower frequencies anyway.
So ideally, you'd want to remeasure in situ to get the best results.

HTH,
David.


Posted By: vertx
Date Posted: 18 October 2018 at 11:48am
Took some measurements of them when in the studio, and tbh I really should get up to speed on sound treatment... Pinch

With EQ, no smoothing


with psychoacoustic smoothing (at least makes me feel a bit better LOL )




Posted By: BP1Fanatic
Date Posted: 18 October 2018 at 8:11pm
Nice build!


Posted By: jamesccart
Date Posted: 16 September 2022 at 8:53pm
any more feedback about these ? I was thinking of doing a mtm with these drivers and the hypex f253


Posted By: vertx
Date Posted: 17 September 2022 at 12:04am
They're still going strong in my mates studio and used 3-4 times a week. I ended up changing the tweeters over to the SB29SDAC-C000-4 a few years later for better dispersion in the top freqs, plus it was 4ohm vs 6ohm for the SS so better for the Hypex, lower dist too I think.

One thing I've noticed over time with the hypex amps is that the smaller ones really do run out of juice on the low end in larger rooms. They sound accurate and transparent but if you have the budget get the biggest ones you can afford. I'm also annoyed you can just bring up the "live" or current config on the DSP you gotta have the original file so over 4 year and 3 computers and multiple config revisions on multiple different speakers in different physical locations it's a bit of a pain not being able to just show up, plug in, and adjust the config (other than with the additional input EQs).

The Volt 8" is great, but I'm not bothering with any more Volt/overseas drivers with sbacoustics made on my doorstep they have a driver for just about any reqs/goal/budget.

For an MTM the SB26STCN-C000-4 is also a good choice and it's tiny so you could get your C2C space down a few mm and cross at 2khz still.


Posted By: vertx
Date Posted: 17 September 2022 at 12:16am
These are from this year when the tweeters were swapped out.   

On ax freq resp -6db at 28hz and 22khz


Distortion


Posted By: jamesccart
Date Posted: 17 September 2022 at 12:06pm
so even with 250 to the volt they still could of used more power thats interesting . 
maybe I would need the the fusion523 then . how do you rate the sound quality of the volt driver I know its only an 8 but their reputation leads me to believe it will be a really good driver ?


Posted By: jamesccart
Date Posted: 17 September 2022 at 12:07pm
and I find it hard to interpret those distortion graphs any idea of the distortion in a percentage ? 


Posted By: vertx
Date Posted: 18 September 2022 at 6:22am
Originally posted by jamesccart jamesccart wrote:

so even with 250 to the volt they still could of used more power thats interesting . 
maybe I would need the the fusion523 then . how do you rate the sound quality of the volt driver I know its only an 8 but their reputation leads me to believe it will be a really good driver ?


How much power you'd need would depend on your requirements and use case. 125w - 250w in a studio environment is probably OK depending on if you're hitting excursion limits pre or post this drive level, which is going to depend on your enclosure net volume and design. Also your might hit port chuffing limits before you hit 500w peaks into the volt anyway depending on how much port length and diameter you can get into the design.

I like the Volt driver, from memory it's got a nice high BL for an 8" and has a decent sized magnet on it for an 8", excursion isn't huge though, but the poly cone does soften the breakup in the upper freqs pretty well. Would be nice for it to have a vented pole piece but maybe it's not really necessary in a smaller wattage driver. If I didn't have the huge range of sbacoustic options I'd still look as ordering them directly from Volt if I needed. If you're local I'd say give em a go.




SPL and drive level was not calibrated for these so I'd say you can probably only use them as an indication of the distortion profile as a whole.


Posted By: jamesccart
Date Posted: 18 September 2022 at 7:47am
thankyou . uou seem like your quite experienced at making studio monitors or speakers could you tell me what equipment you needed to take those distortion plots please is it just a mic and a program on the laptop ? ii constantly design speakers in my head and Id like to shoot for the lowest distortion I can 
thanks again 


Posted By: vertx
Date Posted: 18 September 2022 at 11:47am
For the graphs in 2018 (at the start of the thread) I was using Dayton EMM-6 and Focusrite Saffire 6 interface and Room EQ Wizard at 44.1khz. For the more recent measurements I would have used an Earthworks M30 + Focusrite Scarlett 2i4 and Room EQ Wizard at 96khz. REW is a great tool for measuring lots of audio related things and there's a lot of great tutorials around for the software. If you are software inclined don't be afraid to give a CAD program like Solidworks or Fusion a go as it helps you get the ideas out of your head and "onto the page" so to speak.


Posted By: jamesccart
Date Posted: 18 September 2022 at 12:13pm
thanks how do you rate the sound of the volt speakers you think they're as good as it gets sound quality wise or those sb drivers you mentioned just as good I see they have loads of good looking not so expensive drivers available 


Posted By: vertx
Date Posted: 18 September 2022 at 12:56pm
All the drivers I've used from Volt have met expectations but I have only used a few really.
Does sbacoustics make an 8" woofer as good as the BM228.8 ? Possibly, but driver selection for me is more about availability, lead time, ability of manufacture to fill large or small orders, cost to performance ratio, reputation of manufacture, etc. It's pretty easy to put a lot of expensive drivers in a box with a bad crossover and get worse performance than putting ok drivers in well implemented enclosures with intentionally designed crossovers. Subscribe to Voice Coil, watch Bennett Prescots and videos on YouTube, read lots of forums (and filter the noise out), plus join all the Facebooks groups as there's lots of good stuff in there - sbacoustics loudspeaker fans, and DIY loudspeaker project pad, etc.


Posted By: jamesccart
Date Posted: 01 October 2022 at 9:37pm
thanks for taking the time to reply . your right there's lots of nice looking sb drivers the textreme midbass and tweeter look really interesting I'm not usually into fancy cone materials bit these do seem to offer some real advantages over the usual suspects . I'm going to try to get myself some measurement equipment and tinker about with producing some of the designs I've got floating around in my head 



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