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Multi-Way Conventional loudspeakers with crossovers

Looking for a euphoric mid-range driver - polymer driver?
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Old 28th September 2018, 11:38 AM   #21
Dave Bullet is offline Dave Bullet  New Zealand
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What is your budget for midrange drivers and whole system?

I'm running Seas L15 aluminium for midrange duty. good detail but many pop recordings need the good ol' BBC dip (3-4KHz -5dB ) to be listenable.
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Old 28th September 2018, 11:55 AM   #22
stretchneck is offline stretchneck  United Kingdom
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Quote:
Originally Posted by Dave Bullet View Post
What is your budget for midrange drivers and whole system?

I'm running Seas L15 aluminium for midrange duty. good detail but many pop recordings need the good ol' BBC dip (3-4KHz -5dB ) to be listenable.
No budget set yet, or even design, this is still at the scoping out stage - I do have the BBC dip in my transmission line speakers (kevlar mid range in this case). I'm debating doing a linkwitz inspired design, but perhaps with some Spendor/Harbeth driver influence - I have no idea how this will turn out yet. The 3kHz dip does aid the spaciousness of sound. B&W 802D's apparently have this same dip, as do many other brands of speaker - but this is more of a crossover / design issue than driver cone material choice that I'm trying to get to the bottom of.

Coincidentally Linkwitz LX mini did sound noticeably more natural and effortless than my existing transmission line speakers with Kevlar cones - and the LX mini uses SEAs Alu. So I do know that good design can change the voicing - especially if the breakup area of Alu cones is avoided.

I never had the chance to compare the 'natural expression' of the LX mini to a Spendor or Harbeth, so struggle to compare there. Huge difference in their design approach.

Last edited by stretchneck; 28th September 2018 at 11:59 AM.
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Old 28th September 2018, 01:00 PM   #23
Juhazi is offline Juhazi  Finland
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Stereophile has measured som Spendors and Harbeth 3-ways

This is directivity of Spendor Classic SP100R2 (looks like LR4 xo by step response)
Click the image to open in full size.

and this is Harbeth HL5 (looks like LR4 too)
Click the image to open in full size.

Most 2-ways nowdays are crossed around 2kHz, which means that tweeter gives wide dispersion around 3kHz, while a 3-way with usually higher xo and smaller mid diameter have bloominig around 4-5kHz.

My first hifi-speakers in ´70s were 3-ways, so were second in 80's. Then with HT systems I tried to learn listening to 2-way sound for 12 years starting in 2001 - hard times...
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Old 28th September 2018, 02:49 PM   #24
stretchneck is offline stretchneck  United Kingdom
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Juhazi - I think you might have just hit the nail on the head! Perhaps what I am calling rich, 'wet', creamy for the want of better words, is perhaps mid-range bloom in the 4-5kHz.

Getting slightly more modern, the Spendor D7 shows the same:

Click the image to open in full size.

How have these manufacturers introduced bloom in this specific region?

Do stringed instruments, like violins, potentially have a strong resonance in this zone?
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Old 28th September 2018, 03:06 PM   #25
krivium is offline krivium  France
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Hi,
The region you are talking about is the result from mismatch in directivity between drivers ( evident in both the Spendor graph). The gooseneck you see surounding the area is the place where the filtering take place. This is the result of different drivers diameters having different directivity (the larger drivers start to beam lower in frequency) and center to center length being superior than 1/4 the wavelength at xover freq.
This is typical from 'regular' threeway layout (WMT) and in my opinion this is an artefact which is not nice at all ( in fact this is what i've tried to escape from with my own main which are WMT layout).

I tried to mitigate the effect using a Linkwitz transform on medium (which is closed box loaded- to lower the xover point which initially was 750hz to 500hz for a 15" to 3") and FIR xover to extend bandwidth of mid and have higher xover point ( from 4,5k to 6k- outside the critical frequency range ( also known as inteligibility range :300hz/6khz)of our hearing). Fir xover steep slope help in that it make approaching cone breakup less of an issue.

Overall i prefer the rendering with this setting but the loudspeaker still have a gooseneck in the 500hz freq range and i had to accept the loss of 6db max spl.
I still prefer 3ways to 2ways but now i target to diy a speaker design solving this gooseneck issue ( not even power transfer to the room, unbalanced power response).

Last edited by krivium; 28th September 2018 at 03:13 PM.
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Old 28th September 2018, 07:33 PM   #26
stretchneck is offline stretchneck  United Kingdom
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Thanks krivium - this makes sense, so even though this is not your preference, are you able to confirm that this creates ‘bloom’ and a sound similar to Spendor/Harbeth in the key crossover region?

I know there are lots of factors at play here, I’m just trying to get to grips with how much the drivers plays a role and the crossover. I guess a mini dsp would be a quick way for me to evaluate these effects myself.

Anything more on ‘gooseneck’? There doesn’t seem to be anything on the web about it.
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Old 28th September 2018, 07:37 PM   #27
rhubarb9999 is offline rhubarb9999  United States
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Quote:
Originally Posted by jtgofish View Post
Dynavox make some drivers that strongly resemble some of the classic Dynaudio drivers.
I am using the Dynavox 7" drivers in my current Wilson clones .. they are excellent.
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Old 28th September 2018, 08:11 PM   #28
Juhazi is offline Juhazi  Finland
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Sure not much about gooseneck in the web... but the modern trend in loudspeaker design is controlled and smooth directivity, whic is typically rising towards higher frequencies. This works well when on-axis response is flat. Olive, Toole and many others have published many psychoacoustic studies about this, a glimpse here Speakers that follow this come often from JBL, Revel, Avalon, Vivid audio, KEF, Elac, Genelec etc.

However, despite of that, we have some habits, we are accustomed to certain sound, we prefer certain sound, some music styles work best with certain balance etc. For example the "BBC monitor sound", "Cerwin-Wega sound", "Quad electrostat sound", "B&W sound" etc. etc.
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Last edited by Juhazi; 28th September 2018 at 08:14 PM.
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Old 28th September 2018, 09:18 PM   #29
stretchneck is offline stretchneck  United Kingdom
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Quote:
Originally Posted by Juhazi View Post
Sure not much about gooseneck in the web... but the modern trend in loudspeaker design is controlled and smooth directivity, whic is typically rising towards higher frequencies. This works well when on-axis response is flat. Olive, Toole and many others have published many psychoacoustic studies about this, a glimpse here Speakers that follow this come often from JBL, Revel, Avalon, Vivid audio, KEF, Elac, Genelec etc.

However, despite of that, we have some habits, we are accustomed to certain sound, we prefer certain sound, some music styles work best with certain balance etc. For example the "BBC monitor sound", "Cerwin-Wega sound", "Quad electrostat sound", "B&W sound" etc. etc.
Yes, you are quite right - this is about personal preference. Designing for personal preference seems to be quite a challenge!

It is also possible, that the sound that I like is not related to the design of the crossover - I would still like to mimic the midrange voicing of Spendor / Harbeth, but I did a little experiment with some earphones I have...

Vice soundtrack on spotify, follow the link below, Track 4 'You made me breakfast' there is an Orchestral part of the music 39 seconds in that I will use as the basis for discussion.

Vice (Original Motion Picture Soundtrack) by Hybrid on Spotify

With AKG K3003i (hybrid design dynamic driver with crossover to balanced armatures), as you would expect of this high end earphone - completely neutral clean clear sound.

Listen to the same track with a Sennheiser IE80 and 39 seconds in you get a lot more bloom / reverberation - it's coloured compared to the K3003i - but it sounds much more satisfying to me. IE80 is a single driver, no crossover. I'm trying to work out what causes this, so the design principle is known.

I don't have the technical ability, or perhaps the audiophile language, to describe or potentially design for this trait... or voicing if you will.

Overall I prefer the K3003i with it's flat frequency response, but with stringed instruments (e.g. violins like 39 second in to this track) there is a synergy and tone that is much more enjoyable with the IE80.

It could be distortion caused by an impedance mismatch, lots of reasons.

Perhaps there is no single answer to this and it might not be possible to objectively test.

Part of my question on polymer drivers is really to do with how they affect the overall voicing of a speaker.
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Old 29th September 2018, 01:07 AM   #30
krivium is offline krivium  France
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Hi,
About the 'gooseneck', this is well known issue, at least from pro world: Live/PA sound system suffer from this kind of behavior as it induce some crowd areas are not totally covered when this type of layout is used. Worst this is frequency related so it means some frequency bands are not reproduced in some place...
I've already seen an analysis of a TMM PA loudspeaker showing same kind of graph on Prosoundweb site but can't find it now.

About my own loudspeakers ( Technics SB-M2) i won't tell they have 'bloom'. Frequency wise and on axis they are neutral sounding and well behaved ( even when they was 'stock': passive filter).
What i can tell you about the gooseneck is that they are not easy to position in room. I find them not to interface easily with difficult to find sweet spot. Stock there was always something annoying me in the 750hz range. They have this medium transparency i find appealing in threeway but they are a bit 'muddy' from 500hz to 1k.
Once triamped and xover points changed this seemed to be clearer but the 'mud' character seems to have followed the woofer to medium xover point but it is less pronounced.
Relative to the tweeter extending the high freq to 6k and changed the slope from 12db/octave to 180db/octave changed the sound too. There is probably more gooseneck than before up there but the minimal overlap and shift of frequency in freq range where we are less sensible makes it much less an issue for me.

But this can't be translated to something related to Spendor or Harbeth: first the technology of drivers is different for sure ( mine are 'flat' membrane aluminium honeycomb for all drivers) and their diameter are not usual choice: 380mm, 80mm, 28mm.
Second the cabinet is really different in size ( mine are 850×540×400), shape (beveled edge) and i suppose in wall thickness ( from what i've seen 5cm front wall 3,5cm for others). The cabinet are fairly dead and weight a good 50kg each. Last the filter are differents, even more since triamped with dsp.

I suppose Harbeth or Spendor may stick to BBC philosophy about wall thickness: small, resonant with damping added. Maybe you should search this way as it could be one of the reason of what you call 'bloom' in the mid imo.

Last edited by krivium; 29th September 2018 at 01:21 AM.
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