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Multi-Way Conventional loudspeakers with crossovers

Achieving full range sound in typical British living rooms - IPL Speakers S2TLK CD3.0
Achieving full range sound in typical British living rooms - IPL Speakers S2TLK CD3.0
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Old 18th March 2018, 12:30 PM   #11
stretchneck is offline stretchneck  United Kingdom
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Any DIY versions of 3 way cardioid speaker, like these maybe :

Krypton3 | Amphion

Are the Dutch & Dutch 8C and Kii Three’s Cardioid?
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Old 18th March 2018, 01:38 PM   #12
andy19191 is offline andy19191  Europe
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Quote:
Originally Posted by stretchneck View Post
Lots of stuff on forums elsewhere, which I've tried not to replicate, instead I'm trying to pass on the knowledge that I've gained as a beginner to DIY speaker building.
Good to see an interest in DIY speakers and, in particular, room responses. The construction information looks good and useful but, as others have pointed out above, you are a bit wonky in places on the technical side.

In terms of room integration your 6.5" 2 way speaker is no different to any other 6.5" 2 way speaker except around the tuning frequency (which is what?) most of the sound is emitted near the floor. This will make a difference but whether for the better or worse is unclear. The frequency is likely too low to help with floor bounce (direct sound and sound bouncing off the floor cancelling).

As mentioned above, the design of your speaker does nothing to eliminate the cancellation off the front wall. If you place the speakers close to the front wall the baffle step correction in the crossover will likely need reducing although this can be successfully tackled with your room correction software. An example of a DIY transmission line type speaker that is designed to be placed flat against the wall is the Daline from the 70s. Note it is wide and shallow to reduce the effect of the reflection off the front wall. An alternative approach is to place the woofer/s on the side next to the front wall and the midrange on the front far enough forward for the first front wall cancellation frequency from the midrange to be below woofer/midrange crossover frequency. The progressive beaming of the midrange with frequency then reduces the strength of the higher order cancellation frequencies.
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Old 18th March 2018, 02:20 PM   #13
RobWells is offline RobWells  United Kingdom
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Reflection from backwall is probably meant to mean the back wall of the speaker box (not the room) ie the transmission line absorbs the back wave of the driver and stops it reflecting back through the cone.

Like the BW nautilus concept ?
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Old 18th March 2018, 02:52 PM   #14
Scottmoose is offline Scottmoose  United Kingdom
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That is accurate, or it can be (although a competently designed box of other varieties should do similar). To apply it to external conditions though is nonsense, unless we're going to chuck basic laws of physics into the bin.

What you may be hearing is simply a better damped bass alignment which interacts with the room differently. TLs of the IPL type tend to do this well, as they typically target a well-damped LF response. That's the primary reason they can work quite well near boundaries. Another possible cause is simply hearing the difference between a speaker of different size with different drivers mounted in different positions from previous speakers in the same space. Both of these are well-known factors & I doubt anyone would disagree that they can & do have a significant impact on behavior. But assuming the same drivers mounted on baffles of identical size & shape, with identical vent positions, the dispersion pattern of a 40Hz wavelength (for e.g.) couldn't give two hoots whether it was generated by standing waves or cavity resonance.

Which shouldn't take away from the congratulations on your build. IPL make nice kits.
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Last edited by Scottmoose; 18th March 2018 at 03:18 PM.
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Old 18th March 2018, 04:20 PM   #15
scottjoplin is offline scottjoplin  Wales
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Quote:
Originally Posted by andy19191 View Post
An example of a DIY transmission line type speaker that is designed to be placed flat against the wall is the Daline from the 70s. Note it is wide and shallow to reduce the effect of the reflection off the front wall.
I have a couple of B110s and T27s with nothing to do

I can personally attest this http://www.ejjordan.co.uk/PDFs/Eikona_VTL.pdf works well against the front wall
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Old 18th March 2018, 04:50 PM   #16
planet10 is offline planet10  Canada
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Achieving full range sound in typical British living rooms - IPL Speakers S2TLK CD3.0
Quote:
Originally Posted by stretchneck View Post
...Basically what I'm trying to say is that the sound from the rear of the speaker driver is effectively eliminated in a transmission line design, with only frequencies 200Hz and lower leaving the front termination of the transmission line. This means that the bulk of frequencies 200Hz and higher are not emitted towards the wall behind the speaker (the front wall that the listener is facing) - and therefore cannot go on to produce acoustic nulls. I hope this makes sense?
I phrase that idea as “the TL sucks the backwave down the line and damps it out”.

Sometimes a line will use some of that output to reinforce the bass (likely in your IPL from the limited amount of damping). One tries to keep the main line harmonic and kill all the harmonics above it as they will cause ripple as they move in and out of phase with the output from the front of the speaker. The desired bandwidth is much smaller than “under 200 Hz”.

The issue that your diagram is showing is independent of the box type and is related to the radiation from the front of the speaker. It is caused by the distance of the speaker from the wall.

Your IPL is end-loaded and the only measure to mitigate ripple is the pre-chamber. Earlier in the week i speculated about a similar “daline” that mounting the driver on the “back” would get one some driver offset and help kill ripple.

IPL has been shipping TL kits since before good TL modelers arrived on the scene and still use the same classic design scheme. Not to say that the results ar enot satisfying, but one wonders if their performance couls be further improved with a little tweaking.

Achieving full range sound in typical British living rooms - IPL Speakers S2TLK CD3.0-ipl-line-jpg

Quote:
For someone like me who is trying to achieve good sound quality, but in near wall placement, it made a big difference.
As stated earlier, the TL aspect of your speaker has no affect on the issue of ripple caused by the distance to the front wall (i personaly think of it as the back wall, as in the wall behind the speaker). That distance only has an affect on the frequensies at which the ripple occurs.

dave
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Old 18th March 2018, 04:54 PM   #17
planet10 is offline planet10  Canada
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Achieving full range sound in typical British living rooms - IPL Speakers S2TLK CD3.0
Quote:
Originally Posted by scottjoplin View Post
...or as far away as possible so that reflections are delayed...
Distance affects the frequencies at which things start to happen. Move far enuff away and they start to get buried in the room response.

dave
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Old 18th March 2018, 05:01 PM   #18
planet10 is offline planet10  Canada
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Achieving full range sound in typical British living rooms - IPL Speakers S2TLK CD3.0
Quote:
Originally Posted by andy19191 View Post
If you place the speakers close to the front wall the baffle step correction in the crossover will likely need reducing although this can be successfully tackled with your room correction software. An example of a DIY transmission line type speaker that is designed to be placed flat against the wall...
Scott and i have recently revisted this idea. It uses an ML-TL with bass tuning that is intended to work well with near or on wall placement. Wide and shallow tends to minimize the room placement issue that stretchneck has been erroneously associated with a TL.

http://wodendesign.com/planset/Popla...LTL-teaser.pdf

dave
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Old 18th March 2018, 05:58 PM   #19
andy19191 is offline andy19191  Europe
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Originally Posted by scottjoplin View Post
I can personally attest this http://www.ejjordan.co.uk/PDFs/Eikona_VTL.pdf works well against the front wall
With respect to wall placement it is similar in concept to the Daline and I would expect this to work fairly well. However, the drawing specifies no damping in the line which has turns and step changes in area. If damping is not specified elsewhere this will let all the line modes through not just the lowest plus it will have resonances associated with the height of the speaker. The stuffing at the top is likely sufficient to damp higher frequencies but the lowest few unwanted modes I would expect to be significant and audible. Measurements would show one way or the other.
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Old 18th March 2018, 06:13 PM   #20
planet10 is offline planet10  Canada
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Achieving full range sound in typical British living rooms - IPL Speakers S2TLK CD3.0
Quote:
Originally Posted by andy19191 View Post
... it is similar in concept to the Daline and I would expect this to work fairly well...
Sims show that the Jordan VTL does not work well… Scott has removed the back from his pair and turned them into an OB.

dave
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