JL Audio Fathom

Hi @james633  : " Harrison Labs inline highpass  $27 ( single capacitor installed between the preamp and amp) " 

It seems to me the best alternative/option for @upstateaudiophile  As a fact I'm doing something similar directly in my ML 20.6 monobloks that are coupled ( by design ) at the input and it's here where I changed the input cap for a lower and better quality cap that makes the high pass at around 87hz.

Your very good advice.

R.

Dear @james633  : All speakers ask for current not voltage.

Before I posted in this thread I analize the Sabrina and Mac and from this " bad " realationship " I gave my advise to the owner to change the subs for ones that uses low and high pass filters crossing at around 100hz and with that the Mac will be running alot better in the 4 ohm tap and the subs will handled from there and down to 16hz and with all those the owner system will be improved in its overall quality level performance.

He says that is satisfied with the ML subs what seems to me that he has a misunderstood in the whole subject.

R.

Dear @jastralfu  : Look, Mac works with autoformer from 1967 but that just not says they are perfectly rigth about because it's not. Any additional device in an ampp design ( as the autoformer ) only degrades the MUSIC signal no matter what.

No, that Mac is not really ready to handled with aplomb that 1.1 ohm speaker impedance.

Those are facts that I can see or you don't understand very well or you have a misunderstood about.

@james633  is rigth: " autoformers are use to match the load to the amp " but not for that to low 1.1 ohm impedance in a critical and very often present in MUSIC as 90hz and wha surround that 90hz.

That's the issue.

R.

Dear @jastralfu  : In a critical 90hz frequency and does not matter what that 8950 can't handled it and the problem is all what surrounded that reproduced 90hz frequency as the overtones/harmonics that puts colorations in the mid range and even in the HF and obviously in the mid-bass.

No single amplifier where the audio signal must pass through transformers/autoformers instead directly to the output bipolar devices could be considered up to the task.

Sorry @upstateaudiophile  but I'm not talking of what you like it but what is rigth and what's wrong because these are the facts the " I like " has no objective foundation it's just what we like but facts are way different.

R.

@upstateaudiophile  : Your WA Sabrina are  not well served by your integrated amplifier that has not the abiñlity to handle with aplomb that 1.1 ohm impeance at that critical and way important frequency range that affects at least 2 octaves and its developed MUSIC harmonics and additional to that the MUSIC signal is obligated in that integrated amplifier to pass through an autoformer ( transformer ) instead directly to the output transisttors.

You own to very high quality speakers for that meiocre integrated amplifier. Sorry but thgis is the facts that normally owners don't want to hear/read it.

R.

Dear @upstateaudiophile :  The main issue and target with added subwoofers is to achieve first than all a benefit to lower the IMD in the main speakers as can be in your WA Sabrina X and a side benefit is to have a lower and better bass range handled by a dedicated amplifiers and woofers in those true active subwoofers ( I'm not talking of your ML but any self powered true subwoofer. ).

To maximization those 2 targets you need that the subwoofers must be sealed design and needs to comes with not only low pass crossover filter but it's desired high pass crossover filter too to take advantage and really lower that high IMD that your Sabrina has in this moment due that its woofers crossover the mid range at around 300hz and from here down to 30hz and this is what develops that IMD levels that with the sub high pass crossover filter ( or external High pass. ) will permits a lot better quality levels in the Sabrina mid range, high frequency and mid-bass ranges.

To all those happens and you really can enjoy your system as never before you need to croosover both crossover filters at around 80HZ. Other great benefit that you will have is that at 90hz the Sabrina woofer impedance is at 1.1 that it's really low to handled with aplomb by almost any amplifier and this fact develops higher distortions that makes a degradation in all your room/system quality level performance.

Your ML subs can't do the job neither the JL ( has to high THD. ) and you can go with a noy to expensive alternative like these Velodyne that measured at 20hz and over 100 SPL the lower than 0.5% THD that no JL can even dreams:

Digital Drive Plus - Velodyne Acoustics

Regards and enjoy the MUSIC NOT DISTORTIONS,

R.