Top speaker thoughts  
Monday, May 17, 2021, 19:09
Posted by Anders
What could one do with B&C 15NDL88, FaitalPro HF146 and XT1464, right now I'm thinking sealed alignment, ~80dm3, in an oldschool inspired way, I know what you are thinking but I'm fully aware of the potential thermal problems, but these speakers will not see such power levels very often if at all.

By oldschool I mean wide baffle, shallow and trapezoidal enclosure, think JBL SR47XX series and similar but with a hint of modern elements, something just feel right about it, to me at least.

It is however not without hurdles, the wide baffle (~600mm) will most likely cause diffraction artefacts in the low midband, meaning well below ~1kHz XO for the 15NDL88, and the sealed alignment with a Qtc around 0.55 will mean that the f-3dB will be set around 100Hz, the excursion will not be limited by a Helmholtz function, and so on...

But why take the easy option and follow the standard 50Hz tuned BR recipe of the day when instead one can go marching with a defiant smile straight into the chasm of despair and frustration, it will if nothing else be entertaining and educational.

Let's see how this develops, right now I'm here:

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poor mans surround adventures 
Wednesday, April 14, 2021, 19:54
Posted by Anders
Long time no post, between the ongoing pandemic and two energetic kids there has not been much time to post what has been going on.

To tell the truth not that much has been going on, but I would like to show one of the mini projects there has been time for, a poor mans surround system experiment.

It has its roots in the well known and very old, very basic Hafler circuit, where the rear surround channel consist of the difference between the two existing front channels, and the center is a simple stereo sum to mono.

It it based around a 1:1 15kOhm line transformer, commonly used in audio ground loop isolator filters, which is where i got mine, other than this you need speaker terminals and RCA chassis connectors as well as a couple of 10kOhm resistors.

In this case both of these circuits operate from a standard two channel amplifier speaker level outputs, and the leave you with either center or surround line channels, all with galvanic separation.

An attempt, yet to be verified (DO NOT USE) to combine these into a one box solution is on the table and I am also trying to figure out if there is a way to get channel separation for two rear surround outputs, but this remains to be seen it it can be realized (I'm a speaker nerd remember).

First the rear surround channel:

Then the center channel:

And lastly the untested, unconfirmed and "not recommended to try" alternative, do not use, I put it here just to show where I'm at.

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Locally sourced power 
Monday, December 9, 2019, 20:01
Posted by Anders
I figured I needed to try out the labgruppen LAB1600 since I have read positive comments about their sonic performance in various forums, both international and domestic, hopefully I can get my hands on two more since they should also be a good match for the ROAR15's if running them bridged amounting to ~1,6kW/driver (FTC 8 Ohm).

LAB1600 on the far left.

Initial low level listening confirms this, as a top amp (>150Hz) it sounds very good indeed, clean, detailed and controlled, and as sub amp it keeps this signature and tightened thing up significantly, more definition and punch to put it bluntly.

In my search for the LAB1660's I had the good fortune of running into another very interesting model from from labgruppen, the LAB1500, this is a rather rare model, I have yet to find any documentation online for it and have requested it from labgruppen.

The LAB1500 is a proper old school beast where 2/3 of the amp is made up of it's power supply with one of the biggest transformers I have seen to date in an amplifier, everything is arranged very neat and tidy, looks hand built, I which I could listen to it but it trips my 10A breakers when I so much as look at it (a fix for this is on the way, i hope) :)
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busy times 
Sunday, December 1, 2019, 18:39
Posted by Anders
I write this from our new home in Kungsbacka (which also happen to be the hometown of lab.gruppen) with the latest addition to the family, my now 5 days old son, i a crib beside me, so it has been busy times but of course there is already a work in progress listening room, it's all about priorities...

Now that there are no wall to wall neighbors to worry about I can stretch the legs a bit and listen at "proper" levels, the kids do not seem to mind, so now I'm looking at getting some new amplifiers, not for SPL reasons as much as sheer curiosity.

Four Lab.Gruppen LAB1600 in good condition would be nice, currently looking around for these, two bridged driving the ROAR15's, one for mid and one for high (some future project teasing), but there are other amplifier candidates as well.

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Monday, March 4, 2019, 12:31
Posted by Anders
Johannes dropped by the other day to have a listen to the ROAR15's, fortunate for me he also brought along a laptop with REW and a Umic.

These measurements where take a in room, so don't stare yourself blind at the results.

Appreture ROAR15:

Distortion ROAR15:

Complete system, bare in mind that this is a room completely devoid of any form of acoustic treatment.

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