Yet another Pensil 10p build

[AEE]

Hello everyone!
This is actually my first post here despite being a member for almost 10 years!

I also finally decided to pursue my first-ever speaker build, having at last decided to go for the Pensil based on the Markaudio Alpair 10p.

I have decided to use 18mm birch plywood, but I'm currently wondering about this: Since the material is roughly 1mm thinner than the material used in the plans i wanted to account for this, but should i prioritize to get the internal dimensions exactly right or should I instead make sure the baffle has exactly the right width? If I just make sure the internal dimensions are right the baffle will be roughly 2mm narrower than the drawings, maybe this is negligible?

I'm thankful for any input, and I'm sure more questions will pop up along the way!

BR Anton

 

[Scottmoose]

Believe me, you aren't going to hear 2mm or so difference. It's 'within reasonable tolerance' as far as the design is concerned acoustically.

 

[grahamgraham]

Have you got a measurement mic?

You'll need DSP or a passive network for BSC etc.

 

[Scottmoose]

Specifically designed not to require it in most cases.

 

[grahamgraham]

With respect, Scott, a large portion of your designs don't get made or measurements are not published. So, beyond the BR/QW function of the box it is a little hard to foresee without intermediate knowledge of simulation procedures.

I built one of your Pensils and it did need BSC. I am recommending prudence in what is a common a procedure in any design. I'm aware that these drivers have a, somewhat, tailored response in this regard.

Besides which it is a great phenomena (BSC) to understand and manipulate considering it is the OPs first build or his potential lack of enthusiasm to be a purist

 

[AEE]

Believe me, you aren't going to hear 2mm or so difference. It's 'within reasonable tolerance' as far as the design is concerned acoustically.

Thanks for the reply Scott, that seems reasonable. Looking forward to starting the build! I received the drivers this week and picked up some wood today.

 

[Scottmoose]

I bow before your superior knowledge of my own designs than I have myself. Including your unique ability to state that 'a large portion of [my] designs don't get made'. Hmm. Your evidence for this statement that most speakers I design have never been built being? I wasn't aware that you lived with me, my friends, or the people I work with. Intriguing.

 

[AEE]

With respect, Scott, a large portion of your designs don't get made or measurements are not published. So, beyond the BR/QW function of the box it is a little hard to foresee without intermediate knowledge of simulation procedures.

I built one of your Pensils and it did need BSC. I am recommending prudence in what is a common a procedure in any design. I'm aware that these drivers have a, somewhat, tailored response in this regard.

Besides which it is a great phenomena (BSC) to understand and manipulate considering it is the OPs first build or his potential lack of enthusiasm to be a purist

I don't have any measurement mic yet. First I will just try to get the speakers assembled and see how they sound without any additional correction. This is also a project for me to practice my woodworking skills, which might actually be the greatest challenge for me.

 

[hobbers]

With respect, Scott, a large portion of your designs don't get made or measurements are not published. So, beyond the BR/QW function of the box it is a little hard to foresee without intermediate knowledge of simulation procedures.

I built one of your Pensils and it did need BSC. I am recommending prudence in what is a common a procedure in any design. I'm aware that these drivers have a, somewhat, tailored response in this regard.

Besides which it is a great phenomena (BSC) to understand and manipulate considering it is the OPs first build or his potential lack of enthusiasm to be a purist

Grahamgraham I'm curious how many commercial speaker companies are using or have used your speaker designs?
How many of your speaker designs have you made available for free to the diy community?
Also how often have you worked with commercial driver designers?
I would also like to know if you have any designs that you ask a donation for that goes to help support Diyaudio?

Thanks.
Bernie

 

[grahamgraham]

Scott and Hobbers, I wasn't attacking anyone's work. My view is that BSC in full range designs is largely a point of preference, is it not? P10 often argues that one should just toe in or out the cabinet to achieve this, others with correction.

As grateful as I am for your many designs to look at and consider, Scott, I have seen very few published measurements of them or simulations, therefore, having a measurement mic is a good way to know what you have when done. I wish I had bought one sooner when I started a couple of years back.

You have focused on one part of my sentence when it went hand in hand with another. This is off topic now and I don't wish to engage to distract from the OPs journey on this build. Keep beans on chill lads

 

[Scottmoose]

No, to be clear, you made a statement based your own conjecture as if it were fact. That is something I politely take issue with. The actual fact is that you do not have any knowledge of the design basis or context applied to any speakers I develop, and you do not have any knowledge about how many I do, how they are designed, who builds them, or who tests them.

For the sake of information (this is not a secret, I've written about it here on several occasions) I stopped posting technical data online some years ago, largely due to the large number of headaches it caused. Measurements are a very useful thing for the designer; they are also, or can be, more trouble than they are worth on forums, since many do not always entirely understand them, or in some cases, what are asking for. For example, requests for anechoic measurements of corner horns. Or other loudspeakers designed to be boundary loaded, and / or user-adjustable. And let us not forget the multiway with midband EQ per client requirements, which certain people shrieked were 'bad' because they 'don't have a flat midband response', despite the fact that they were specifically designed not to (and in fact for reasons on dispersion, in-room power response &c. actually sounded like they had peaking through that range without it). They didn't actually know any of that: they just saw fit to start criticising as though they actually had the confidential hard data and knew the client requirements which only I possessed. And so the list goes on. So, in the interests of preserving my sanity, especially since I have done my best to provide quite a few designs and only have so many hours in the day, I stopped.

Now, step loss correction is something that is generally over-utilised based on insufficient contextual data of the actual in-room performance. Far, far too often, we see excess quantities employed because no account has been taken of what the real behaviour is in the lower registers, which are notoriously difficult for many DIYers to accurately measure, especially those relatively new to audio. The majority of people who build the pensil enclosures of various types find there is little or no requirement for additional EQ; more than 90% based on the feedback I received. Ergo, when people instantly start talking about step loss and recommending such measures before a person has even built it and established whether they have any such requirement, I make the point that, to quote my carefully worded comment: 'specifically designed not to require it in most cases'. That does not mean that in every and all cases they will not. When pulled from boundaries or used with higher damping levels &c., they can. What it means is that in most situations, users do not find it necessary, and establishing a basis is the sensible approach rather than instantly assuming a requirement.

I maintain my advise: to ensure peace of mind for you and the OP, he should instead build Jim Griffin's MLTL, or any alternative that you recommend.

 

[gazzagazza]

To Graham Graham.

I too have built a Pensil enclosure designed by Scott. I'm sure many others have too.

I measured it. It did not need any baffle step correction. It was a very satisfying loudspeaker to listen to.

To the OP. Have fun, build away and enjoy.

 

[Scottmoose]

Glad you liked them.

As noted, step-loss is certainly a matter for consideration, and nobody (I hope) would deny that. My 'concern' on that front is simply that it is often done to excess through insufficient consideration of the actual use / context. In most cases users find no need for it with the pensils as some is already mechanically / acoustically factored into the design. As I say, not every case, and nobody claims they are 'perfect' or anything like -they were after all also designed to be as physically simple and easy to build as possible. But in a majority, users tend to find the balance requires no additional low[er] frequency EQ, and I tend to advise people to try them first and only add EQ if they find it necessary rather than working from the assumption it will be from the get-go.

 

[hobbers]

AEE my apologies for taking your thread off topic, this will be my last post on it. If feel this needs to be said.

We've lost very valuable, knowledgeable and important members of Diyaudio over the years due to other members thinking they know more about that members own designs or products. We unfortunately have no more access to that knowledge. Mostly because of members who think that because something that worked well with their build that it should be applied to every build.

Grahamgraham bsc is something that can and sometimes should be applied to all speakers. To have pointed out Scott in the way you did and made a comment about his products, that would have required inside knowledge, was unnecessary.
You were right to bring bsc to AEEs attention, as a suggestion to try it if he felt the need for it, and is something he should keep in mind.

AEE best of luck with your build, I'm sure you'll get many hours of enjoyment from them.

Bernie

 

[chrisb]

As a point of interest, it long being an area of technical interest for what I’m sure he’ll have no issue with me describing as his essential math geek, Dave compiled a series of discussions of the general problem of Baffle Step Loss / diffraction on his non-commercial site several years ago. Transmission Line Speakers -- Technical Articles

 

[planet10]

I built one of your Pensils and it did need BSC.

Did you remove some stuffing 1st? And room placement?

We have built a number of Pensils and did not need BSC — we have very rarely needed it.

BSC is oft misunderstood, and often used because many like an exagerarated bass. The act of bringing up the non-flat on-axis response, but at the expense of too much power response. And often the parts in a passive BSC subtract more than they add.

In the end it all comes down to taste.

dave

 

[BJosephs]

I built the 10p Pensils a few years ago. I still use them. When I got a mini DSP and U-MIK to integrate my subs I did experiment with BSC and ultimately needed none. Typical home listening spaces have so many ups and downs in response that I think you'd struggle to detect it unless you were far enough from a boundary to get the full -6db step response. The front baffle on mine are about 18" from a wall.

Build them stock, don't fret about a mm or two here or there (as long as everything fits) and keep the back removable so you can adjust the fluff. Great first project.

 

[dmar836]

One of many designs I've contemplated but I no longer feel confident asking opinions. DIY lesson learned: Don't share your build, listening impressions, or other info. Just pick a design, build it, and if it doesn't meet your expectations, modify it in secret(just don't share that part) or destroy it/pass it on and pick the next project.
Dave

 

[twocents]

Hey Dave (dmar836) – just want to say welcome to diyAudio! I see this is your first post and hopefully what you expressed will not be your experience on this forum. Yes, you will find naysayers and nitpickers here too, but by far the most members here freely share their (sometimes invaluable) knowledge, experiences, biased opinions and sometimes irrelevant info. I have certainly gained so much by reading, looking, copying and asking on this forum and a whole new world opened up for me. I am extremely thankful for all the members that contribute here. If it was not for this forum I would never have been able to build and enjoy the great headamps, preamps, power amps, dac and speakers I have built up to now.

I hope your opinion changes and that you too will start contributing to the benefit of others here.

 

[Scottmoose]

Quite so.

If I may suggest -wrong lesson learned. If you feel inclined (it is hardly an obligation) do share 'your build, listening impressions, or other info'. This is a welcoming place. What I suspect you read above was not somebody objecting to a person adjusting something to suit their requirements. It was somebody objecting to a blanket statement that had been made without any kind of caveat or context, which was then followed by a further statement that was, without beating about the bush, a pure invention.

Adapting is good. Opinion is good. Discussion is good. Questions are good. All welcome. Blanket statements of opinion made as though they are universal fact though do get challenged, as you would expect and hope for.