Jump to content
The Classic Speaker Pages Discussion Forums
Aadams

BA/AR LST Hybrid (BLAST Stack)

Recommended Posts

Just wanted to let you know that the Sherwood AP-7020 Preamplifier has a built in

2-way active crossover that might be of interest.

Share this post


Link to post
Share on other sites
51 minutes ago, Pete B said:

Just wanted to let you know that the Sherwood AP-7020 Preamplifier has a built in

2-way active crossover that might be of interest.

Thanks. Check your feed.  Also your message box is full again.

Adams

Share this post


Link to post
Share on other sites

How good is this system?  From the beginning this has been an experiment.  One big concern was becoming so invested emotionally or financially that I could not admit failure or remain objective.

I avoided the financial problem by refusing to spend money on anything that could not be employed in another system or given away without regret.

The subjective, emotional investment was avoided by knowing that I always had 9s and 3as as reference and backup when I needed to calibrate my ears and if the experiment failed I would still have good sound.

Because I have not moved this system into a big room to assess it directly against my 9s and 3as, I will not say that it is an unequivocal success but, in this small 1000cft room I find myself frequently smiling at what I hear and am astonished at how little effort and time it would have taken had I known the direct path at the time I started.   

The cost.  If you have read the opening post to this thread you know the original cost included a new pair of powered sub-woofers for which I was willing to spend up to $1000 and was 80% of the budget.  Except where noted below everything else was purchased used or already in my possession.   After the sub-woofers were returned and this became a “Frankenstein” experiment the incremental cash outlay stood at around $200.  In its current and final form, the total expenditure is very close to $750 as follows:

Pre amp – Pioneer 850 that once drove AR58s system   

Equalizer- Realistic 10 band already in use with AR58s

BA CR65 speakers x 6   Approx $30 each

New Crown amp for 2 ohm load- $299

New Crown amp to isolate and drive AR58 woofer $250

New XLR cables $15

AR 58s – Previously used as separate system and AR9 standby parts bin.

Total incremental cost was $744

If the project had failed the Crowns would be used on my 9s and 3s so there never was real fear of failure.

Aadams

Edited by Aadams

Share this post


Link to post
Share on other sites

I should give credit to a recent discussion in the AR forum for providing impetus to achieve this version of the system.  Had I not looked more deeply into the capabilities of DSP regulated amps as a result of that discussion, I believe this system would still have its previous klugey, less resolving, form. 

So, hats off to the CSP!

Adams

Share this post


Link to post
Share on other sites

Adams,

I have been highly impressed by your dedication to better sound through experimentation.

I have been trying to blend speakers of different brands and sizes way back when I still owned a pair of AR9’s. I was looking for more natural sounding vocals and clarity in general. I liked the bass of AR9 but above the midbass, NHT Zero, Radioshack LX4(with Linaeum tweeter) and several other brands with stiff metal drivers sounded more natural to me. After I sold my AR9’s, I acquired a pair of NHT 1259(the woofer  in NHT 3.3). I also bought a pair of HSU Research TN1220 subwoofers capable of responding to below 20 Hz. Over the years I have paired many more commercial and even some DIY speakers to serve as tops to use with either NHT 1259 or Hsu. I have learned that there have been real advances in reducing the coloration and distortion of the drivers. Technologies such as symmetrical magnetic drive(JBL and Scanspeak), shorting ring for reducing the voice coil inductance(very common now), anodized aluminum cone(Ceramic) for stiffness, waveguide for tweeter and software for better crossover design, all were developed in the past 30 years. More recently, my favorite tops are Infinity R162 and R152.

https://www.soundandvision.com/content/infinity-reference-r162-speaker-system

Among the DIY speakers I like is a simple 2-way using Dayton RS 225-4 and RS28-A4.

I don’t think I have reached my perfect sound yet but I don’t want to stop experimenting either.

Share this post


Link to post
Share on other sites
4 hours ago, ligs said:

I have been highly impressed by your dedication to better sound through experimentation.

Ligs

Thanks for your comment. 

I am not a big experimenter I just fell into this by accident and from frustration with powered subs and their bias toward HT.  I was lucky to stumble upon a good result.    I listen to this system almost every day as entertainment and for evaluation to find flaws and have not changed it since my last post about satellite array positioning, but I will report my impressions in a few months either way.  I think I am being objective when I say It does sound good. The ultimate test will be to make myself move this system to a much larger room but there is too much inertia to make that happen anytime soon.

I agree, there have been huge advances in small speaker systems since AR left the field and there are a lot of good candidates for integrating into this type of system. 

Adams

Share this post


Link to post
Share on other sites

I have devised a way to overcome the inertia of moving this system to a much larger room, but I must wait until an amplifier is returned from being rebuilt sometime within the next 30 days.

This accelerated plan is possible because, for one time only I will violate my speaker ethics and experiment using my 3as as the bass speaker sitting beneath the satellite array.

Using this approach, I will only need to move the array and the very portable associated electronics to a position right beside the AR9s.

This is not a test of 9s against The Stack, rather it is a test to see if The Stack can produce a good sound field from a 15-20ft listening position while I am standing, sitting and somewhat mobile. 

More later.

 

Adams

Share this post


Link to post
Share on other sites

 

The Blast58 stack has been temporarily deactivated. The stack and electronics are now part of a new incarnation---------a Blast9 stack.  I know I said I would use a 3a but I realized it was logistically even easier to use the 9s and I learned something about using AR 4ways in the process.

First, if you do this with an AR 4 way you can cross at 100hz or 400hz but not at 200hz.   200hz seems perfect for a 3 way AR but the 4way doesn’t sound right because, as AR says in the AR9 manual, you will get some unpredictable effects.   AR foresaw that idiots like me might use an external crossover so, way back in 1979 they recommended 400hz for a woofer crossover point and partially explained why.   You could also cross at 100hz but that is a waste of an AR9. 

In the end, crossing at 400hz means you are effectively still running a 4 way system.

How does it sound?  It sounds great.  I tried a couple of configurations you can see in the photos.  The listening position is 15ft away.  I could stand and move around with no dips or peaks apparent while listening to either large scale classical or pop vocals.  The vocals were solo recordings of male and female voices that I heard many times before on this satellite stack. The classical recordings were all Telarcs that show the 3a at its best so, the bar was high.

Does it sound like a 3a?  Close enough to where I could forget which speakers I had switched after a few minutes.  The amount of energy a 3a can distribute is astonishing.  Six drivers in this stack could not quite match its sound signature but sitting at 15ft listening, it is very hard to tell the difference after the switch is made.

All the stuff I said much earlier about comparisons with 9s and 3as and 58s still applies. What has changed is I now know this approach works in large and small spaces. image.thumb.jpeg.fb395be04cd3af09746dda842d973d10.jpegimage.thumb.jpeg.00c83f758fa7cebb0f0d6bec92da49d2.jpeg

Share this post


Link to post
Share on other sites

If you have read earlier posts in this thread, you know I felt there was strong similarity in sound to the 9 and 3a, long before I moved the Sat stacks into the same room.  I also previously evaluated the Blast58 against the standard 58s which showed great dissimilarity in LMR sound quality.

Now that they are all together, I have spent hours over the previous 2 days balancing systems and listening to evaluate the difference in sound between the 3a, 9 and the Hybrid 9 to determine if the difference was sufficient to make me leave the Hybrid9 in place, which was not the original plan.

To review, the Hybrid9 configuration is one DSP amp to the stacks and one DSP amp to AR9s with each amp configured as either high or low pass at 400hz.  To listen to the standard AR9 I must simply reprogram its amp to full range mode, but I cannot directly AB the 9 against the Hybrid as I can the 3a.

Following are the distilled impressions of all that I have heard using repeated listening of a small range of recordings with which I am very familiar.

The Hybrid9 has an expansive sound more like a 3a than a 9.

All three speaker systems sound so similar that if you were to enter the listening area from the rear, almost 30ft away, without knowing which was playing, you could not clearly distinguish which without approaching within 6ft. 

In absolute terms, according to taste, the Hybrid9 may sound a little better than the standard 9 but the improvement over the 9 is marginal and nothing in proportion to the vast improvement that can be had with any AR12” 3way except the AR3a or LST, IMO.

I will soon begin moving the electronics and wiring back to the 58s but just before I replace the Sat stacks I think I will try out the sound of a 4way AR5.

 

Adams

 

Share this post


Link to post
Share on other sites

The 4way AR5 is configured and playing, stacked on the 58s.  The more you do this the easier it gets to dial in these sets of bi-amped dissimilar speakers. They are crossed over at 200hz and I think they are balanced but I will listen for at least another couple of weeks before putting the Sat Stack back on the 58s.

They sound good.  Imagine an AR98 with the sound field of an AR3a.  Because I am listening to a lot of voice, I have the equalizer bumped up maybe Edit : 2db at 2000hz to compensate for the slight on axis mid-range drop beginning at around 700hz.   If I had 2/3 or 1/3 octave unit I could be more precise.  Still it sounds very good.

The only ever problem with AR5s has been the disappointment of missing the big lick when it hits in the music because its low roll off begins around 50hz.  This configuration solves that problem.  You might be able to duplicate this with two powered subs but most of those attenuate at 24db rate and the 5 rolls off at 12db.  It is easier to take active control and impose a high and low pass at a point where both drivers are working comfortably and more than an octave away from a built in crossover point.

More later.

Adams

Share this post


Link to post
Share on other sites

I haven't dropped this thread.  The AR5 tweeters are out for rebuild.  Although both of them worked it became obvious they were lacking in comparison to the Sat stack tweeters.  I will report further on the 4 way AR5s when I get the tweeters reinstalled.

Adams

Share this post


Link to post
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now

×