FLH design Sensitivity compared to Quake, Psycho .

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   Playing around with FLH design, using 15" driver, seems bit of a nom starter to me.

Most 18" FLH designs struggle to get below 50hz (in reality, not a sim), with a single cab.

WSX being the best exception, I know.

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levyte357- Members Profile Send Private Message Find Members Posts Add to Buddy List Old Croc Joined: 27 July 2012 Location: UK, South East Status: Online Points: 7959	Post Options Post Reply Quote levyte357- Report Post Thanks(0) Quote Reply Topic: FLH design Sensitivity compared to Quake, Psycho . Posted: 30 November 2022 at 2:22pm
	Playing around with FLH design, using 15" driver, seems bit of a nom starter to me. Most 18" FLH designs struggle to get below 50hz (in reality, not a sim), with a single cab. WSX being the best exception, I know.
	Global Depopulation - Alive and Killing.

psychotea Members Profile Send Private Message Find Members Posts Add to Buddy List New Member Joined: 03 September 2020 Status: Offline Points: 7	Post Options Post Reply Quote psychotea Report Post Thanks(0) Quote Reply Posted: 30 November 2022 at 2:16pm
	Played around a bit with the "Compound Horn" design type in hornresp. Using an offset driver in a classical horn I wasn't really able to see the improved low end extension (it was there, just very very minimal), however the CH poses some interesting gains. The idea is effectively to have two horns, the main one from the front of the driver as normal, and a smaller separate horn originating from the back of the chamber. Throwing some quick numbers together I was able to come up with http://https://imgur.com/a/HvXqngO - this. Black line = CH, grey line is my previous FLH design. Sensitivity is 1w/1m in half space (2Pi). This is using the same B&C 18DS115 driver. You can see f0 is about 4hz higher (37 vs 33), however sensitivity is vastly improved ~4dB, and this enclosure is around 110L smaller (670L vs 780L); so the f0 could likely be dropped to match in a comparably sized enclosure. The compression ratio is also a much more reasonable 3.13:1, versus 5:1 in the FLH design. One caveat is you can see there is a sharp dip at 70hz, I assume this is some form of cancellation from the two horn paths. There is also a bit more of a "sag" between 43-50hz than I'd like (most dnb basslines sit around 43hz), however this does smooth out http://https://imgur.com/a/BGxIm4q - once you scale up to 4 boxes. In a stack of 4 the f0 point also drops to around 35hz with f3 around 31. The other thing is I'm not at all sure how this type of enclosure sounds. The main reason I am a big fan of sealed FLH (and less of a fan of TH) is they have a very "tight" but aggressive sound (I assume this stems from the fact that the driver sits in a sealed chamber). On the other hand, I find TH to have a less punchy/more "loose" sound -- I'm not sure if this compound horn design would suffer the same issue. With that said, power handling can potentially be increased, as there would be some airflow into the driver chamber - sealed FLH tent to get preeeeety toasty. Does anyone know of any designs based around this CH principle? I saw some early stuff from the paraflex guys, but nothing concrete, and it seems those sketches don't use a flared horn.

VECTORDJ Members Profile Send Private Message Find Members Posts Add to Buddy List Registered User Joined: 11 June 2006 Location: United States Status: Offline Points: 482	Post Options Post Reply Quote VECTORDJ Report Post Thanks(0) Quote Reply Posted: 18 November 2022 at 10:38pm
	Edited by VECTORDJ - 01 December 2022 at 4:25am

psychotea Members Profile Send Private Message Find Members Posts Add to Buddy List New Member Joined: 03 September 2020 Status: Offline Points: 7	Post Options Post Reply Quote psychotea Report Post Thanks(0) Quote Reply Posted: 18 November 2022 at 3:56am
	Ok, so I spent some time building a rough simulation of the HessBH in hornresp. @Nakwa I'd be curious to see how far out I was in the end! Out of curiosity, I also modelled a B&C 18DS115. I was able to achieve a roughly 2db sensitivity improvement from 35 to 80hz, but there are a few caveats: - The compression ratio is quite high at 3.75 (vs 1.8 in the original model) -- again I'm not sure if this is acceptable for modern drivers. The loading on the driver should be fairly even considering the throat chamber (S1-S3) is rectangular. With that said 1.8 is relatively low (I think?) so there might be some room for improvement there in the original design(?) - Volume is increased by ~25L -- but this isn't a big deal at ~4% - Cost: the B&C driver is about 50% more expensive (£525GBP) - but whether this is worth it is up to the builder :P I've attached all the hornresp data here: https://imgur.com/a/vTuKA1F Would love to know everyone's thoughts :-)

psychotea Members Profile Send Private Message Find Members Posts Add to Buddy List New Member Joined: 03 September 2020 Status: Offline Points: 7	Post Options Post Reply Quote psychotea Report Post Thanks(0) Quote Reply Posted: 18 November 2022 at 1:19am
	Also, what was your reason for going for the RCF LF18N405 verus a driver like the B&C 18DS115? Obviously cost is one consideration, is power handling/compression is the other? Edited by psychotea - 18 November 2022 at 4:01am

psychotea Members Profile Send Private Message Find Members Posts Add to Buddy List New Member Joined: 03 September 2020 Status: Offline Points: 7	Post Options Post Reply Quote psychotea Report Post Thanks(0) Quote Reply Posted: 18 November 2022 at 1:06am
	And on the general topic of aiming for 105dB sensitivity á la EM Quake, Psyco X, @Nakwa has a very good article on their website http://https://agency.fr/docs/le-processing-a-outrance-void-stasys-x/ - here (assuming it's working again) discussing how these figures can easily be manipulated. So while I agree that ~105dB should be achievable with modern driver technology, I think we shouldn't hold these figures in too much regard. The JTR Orbit Shifter Pro claims 103dB sensitivity, and in a stroke of madness, this actually matches up with the real-world measurement! Kudos for that.

psychotea Members Profile Send Private Message Find Members Posts Add to Buddy List New Member Joined: 03 September 2020 Status: Offline Points: 7	Post Options Post Reply Quote psychotea Report Post Thanks(0) Quote Reply Posted: 18 November 2022 at 1:01am
	Hey! Thanks for joining us :-) And sharing your HessBH plan with the world. I had a look through the Facebook page, but I wasn't able to find a copy of the measurements you mentioned. Would you be able to share a link? Also, would you be able to share the hornresp inputs? Call me lazy, the plans are public I know :P I would be interested in experimenting with raising the tuning frequency from ~32hz -> ~37hz to see if there are any gains to be had in sensitivity in that area. Similar to the tuning of the JTR Obrital Pro (credit @totallyghost): ~~Though your design does claim to outperform it by quite some margin.~~ Nevermind, I realised I was looking at the 4x HessBH graph :P They definitely seem to be doing quite some magic here to get such a respose in a 530L enclosure. I was also a bit unsure about the +6dB claim on your website (which doesn't seem to be working, by the way). The +3dB sensitivity gain I understand, but I'm unsure where the other +3dB power increase is coming from? While the driver you recommend (RCF LF18N405) is 1500w power handling, which equates to a ~1dB increase versus the 1200w SBH (RCF LF18N401), you mention on your website that only 1200w RMS should be used (I assume due to power compression / overheating?). Edited by psychotea - 18 November 2022 at 4:00am

Nakwa Members Profile Send Private Message Find Members Posts Add to Buddy List New Member Joined: 26 October 2022 Location: France Status: Offline Points: 1	Post Options Post Reply Quote Nakwa Report Post Thanks(0) Quote Reply Posted: 26 October 2022 at 11:03pm
	Hi ! I'm the hessBH designer, randomly finding this topic. All its specs and plans are avaliable at soundagency.fr (in public projects). This design isn't a pure flh horn, it has the driver offseted in a Transmission Line which excites some harmonics that helps the low end ;) Some people built them in France/Belgium and the calibrated measurements with the LF18X401 fits for 1/3/6U, you can find superposition of my sims/measurements on my Facebook post about this design. Edited by Nakwa - 26 October 2022 at 11:05pm

snowflake Members Profile Send Private Message Find Members Posts Add to Buddy List Old Croc Joined: 29 December 2004 Location: Bristol Status: Offline Points: 3012	Post Options Post Reply Quote snowflake Report Post Thanks(0) Quote Reply Posted: 09 August 2022 at 6:44pm
	your rear volume is too large. not reactance annulled (search for Kolbrek in the forum). you need more than four boxes that size to hit 30Hz. Le is probably high enough you need to double click the 'Le' to engage lossy inductance model. what's the throat adapter doing for you? maybe try the system design with driver for a two driver box in 0.5Pi space. you can then split it in half to get a sensible sized single driver horn. use the hyperbolic horn approximator to turn it into a horn of four sections and you can start tweaking the throat.

coolboarder Members Profile Send Private Message Find Members Posts Add to Buddy List Registered User Joined: 23 June 2010 Location: Germany Status: Offline Points: 28	Post Options Post Reply Quote coolboarder Report Post Thanks(0) Quote Reply Posted: 09 August 2022 at 5:03pm
	Hi @psychotea, thanks a lot for joining the discussion. Indeed, compression is high and as said, I am just fiddling around with hornresp without making neither knowing too much theory around it. My horn path is around 3.1m, therefore I was surprised that my f0 is rather high at ~40Hz rather then 30Hz. What' the route to lower f0 here apart from longer horn path if I may ask. The HessSBH I just found (I think on inst**ram) and the other designs of that collective. I have no more info on that.

psychotea Members Profile Send Private Message Find Members Posts Add to Buddy List New Member Joined: 03 September 2020 Status: Offline Points: 7	Post Options Post Reply Quote psychotea Report Post Thanks(0) Quote Reply Posted: 31 July 2022 at 10:58pm
	Funny timing, I was working on an FLH design based on the B&C 18S115 a few months ago. As you mentioned, I figured with the modern driver technologies a much better DIY FLH design should be possible than what is currently out there; demonstrated by what Quakes and Psyco X's are able to achieve. Here's a couple of measurements from my sims. I've modelled sensitivity the same as you for comparison (4v, 2S2P), and max SPL is 1700w @ 8ohm in a stack of 4. Both measurements in 2Pi. I'm happy to upload some more data if you're interested. See here: https://imgur.com/a/aXUDQM0 I aimed to get down into the low 30's with this design, F0 is roughly 32hz (109.2dB), with F3 around 28hz (in a stack of 4). (I have great visions about running small, intimate dance music events with great sound quality and heavy infrabass content music) Sensitivity is within about 1dB of your design, and max SPL is also within ±0.5dB, but as I mentioned dropping ~8hz lower. There are two kickers: - This is big cabinet, about 780L (100~ larger than your latest revision). Granted, not as big as some (cough p*raflex), but still bigger than SBH, WSX, Psyco X, etc. The price you pay for LF extension, hey! - Compression ratio is 5:1. As @fatfreddiescat mentioned, this is much higher than the typical advice of 2.5:1. However, from my sim'ing it seems that a higher compression ratio greatly helps with SPL. I've never been able to find a solid answer on where that 2.5:1 rule is derived from, and whether newer drivers (ie. carbon cones) will be able to hold up (any input is appreciated here) - Bonus kicker: I have no idea how to go about folding this thing :P Also, thanks for linking the HessBH design; it seems reassuring that what we're trying to achieve is indeed possible. Do you know anyone who has built any of those cabs? I wasn't able to find any further information online outside of that website. Their specs appear to match up with the design I've put together (granted mine is 160L larger, and using the more powerful 1700w B&C driver, allowing for the +4-5dB gain in max SPL response). It makes me quite tempted to put one of these HessBH boxes together, considering the more reasonable size and much cheaper driver (around £200). Cheers!

VECTORDJ Members Profile Send Private Message Find Members Posts Add to Buddy List Registered User Joined: 11 June 2006 Location: United States Status: Offline Points: 482	Post Options Post Reply Quote VECTORDJ Report Post Thanks(0) Quote Reply Posted: 31 July 2022 at 3:49pm
	Is the Quake out of Production????